Bonnet scoop on RRC

[Baggy]

Hi All

Has anyone fitted a bonnet scoop to their classic.

Saw a nice 4dr classic fitted with what looked like a GU Patrol bonnet scoop.

It actually looked good ... I've seen a few vents added to the side of the bonnets to
Improve heat dispersal.... but to be honest most were done purely for functionality....not astetics and didn't look good IMO.

I've kept my eye out for any side vents from any vehicle that i could fit that anyone who didn't know classics would assume they were a factory fitment.

As I've not seen any I'm thinking this would be a good alternative.

I know both my 81 2dr and 92 4d both retain heat under the bonnet.

Only looking at doing it on the 92 classic as it's had the guards and doors chopped and large classic flares added.

The 81 2 dr stays as God intended .....original.

Baggy

[Vern]

I have this on mine.
There is actually a thread running at the moment on bonnet scoops and vents etc...https://www.aulro.com/afvb/images/imported/2018/01/761.jpg

[Davo]

I think I have reached the point where I can say I have extensive experience with this - but then again, I might take that back the next time I fool around with engine bay ventilation! This is a real Pandora's box because once you add one thing or change something else, all airflow under the bonnet changes. Because I live in a very hot place, you can just imagine how important this has become for me. Before I did all this, after on hour on the highway, I have in the past lifted the bonnet and felt a "pillow" of hot air on the engine. That air was so hot is was easy to feel it sitting there.

I've cut some ugly holesawed 50mm (or so) holes on either side of the bonnet, at the rear, and also have two small SAAS scoops in the middle of the high parts of the bonnet, you know, on either side of that lower middle bit. Then I've used the same pinchweld Rangies have for door seals to seal the front and sides of the bonnet to the body. This was because I've now got thermo fans and they were pulling in air at the front of the bonnet at idle instead of only through the radiator.

I had the scoops on facing forward, but then realised that this was pressurising the engine bay, which just makes it harder for air to flow through the radiator. So now the scoops are reversed, and testing showed that the engine bay has enough low pressure in it to suck air into these scoops and then forward and down. Bear in mind that these scoops are forward enough to avoid that high-pressure area in front of the windscreen. This seems to work, (until my next experiment, no doubt!), to keep outside air flowing into the top of the engine bay, where all that hot air usually gets stuck. I have to admit that I put then on facing the rear because I had tested them off the car, and airflow over them was sucking air out from underneath. Typically, the opposite happened with them on the car! But it seems to work well. I still have more testing to do.

I don't think you really need this sort of thing down where you live. The biggest problems with heat tend to start at around 35c. Certainly, under 30c these cars shouldn't have any trouble with cooling the engine or with heat under the bonnet. I did all this because at 40c it needed something done.

[gavinwibrow]

I don't think you really need this sort of thing down where you live. The biggest problems with heat tend to start at around 35c. Certainly, under 30c these cars shouldn't have any trouble with cooling the engine or with heat under the bonnet. I did all this because at 40c it needed something done.



Keep going Davo. watching all of this work with some interest, as no doubt are others.

[Baggy]

Vern: That's one lovely looking classic.
Have you cut into the bonnet to assist with heat build up or were there other reasons for putting on the scoop [wink11]

Your choice of scoop is exactly what I'm talking about ... it enhances the look of the classic.

I'll search for the tread as I don't believe I've seen it .... or I've missed it ... or worse ...... forgotten that I'd see it ....


Davo - Thanks for your thoughts ....

Unsure why but this classic (92) seems to be an unusual amount of heat that radiates from the engine bay.

I can feel it through the automatic transmission tunnel .....centre console etc ... checked heater .... that's off and thought by assisting air flow
out of engine bay that would assist.

I've had radiator rodded & cleaned .... so there' no issue with it overheating .... although you have raised issues that I had not thought of.

The classic I saw the bonnet scoop on was one nice rig .... I saw it parked in a house not far from me and was meaning to go there and knock on the door.
Unfortunately they have since move away .....

Cheers

Baggy

[Davo]

Keep going Davo. watching all of this work with some interest, as no doubt are others.

I keep meaning to cover it all in one thread and keep failing! [bighmmm] But I'll try and get to it soon.

[Davo]

Vern: That's one lovely looking classic.
Have you cut into the bonnet to assist with heat build up or were there other reasons for putting on the scoop [wink11]

Your choice of scoop is exactly what I'm talking about ... it enhances the look of the classic.

I'll search for the tread as I don't believe I've seen it .... or I've missed it ... or worse ...... forgotten that I'd see it ....


Davo - Thanks for your thoughts ....

Unsure why but this classic (92) seems to be an unusual amount of heat that radiates from the engine bay.

I can feel it through the automatic transmission tunnel .....centre console etc ... checked heater .... that's off and thought by assisting air flow
out of engine bay that would assist.

I've had radiator rodded & cleaned .... so there' no issue with it overheating .... although you have raised issues that I had not thought of.

The classic I saw the bonnet scoop on was one nice rig .... I saw it parked in a house not far from me and was meaning to go there and knock on the door.
Unfortunately they have since move away .....

Cheers

Baggy

What's on the front end? Bullbar, dinnerplate-size spotties? Is that plastic air dam under the bumper still there? I took mine off years ago before I thought about what it was for - and now I have no doubt it was there to create a low-pressure area under the radiator. I've since made up something to do the same thing. (I think! I really need a wind tunnel . . . )

[Baggy]

Hi Davo,

Photo of front of vehicle ..... unsure about the plastic air dam ..... don't remember seeing anything under there??
As I said ... no issue with overheating but there is definitely an issue of heat build up in the transmission tunnel.

Unfortunately you don't need a 35 degree day ...... the radiated heat .... radio / CD player does get very warm (hot) indeed.
I had a 96 Discovery ... not much newer than the 92 classic (pictured) but no issues there at all.

Vern ... found the thread running on D1 Forum ....thanks.

Some interesting points of view ..... I'm unsure of the large bonnet scoop from the series 79 land cruiser being modified for RRC bonnet.

With something that big I'm unsure the hole / slot you would need with that scoop ..... ITS BIG and that would definitely pressurize the engine bay.

I saw Tombie scoop .... looks like its off a Toyota hilux and its achieved (OK no scientific evidence) what I'm aiming for.
I've been toying with this for a while ....so I've bitten the bullet and picked up a S/Hand GU Patrol (2010) bonnet scoop today ... and its white [smilebigeye]

I'll start fitting it tomorrow ..... worst case scenario ....... I'll need a new bonnet.

cheers

Baggy

[Vern]

My scoop is only there because of my intercooler, it wouldn't quite fit under the bonnet.

[Baggy]

Hi All,

Things to note on a GU Patrol scoop ..... The're not evenly shaped and add to this that a Rangie bonnet (ribs underneath) are not spaced evenly.

The washer sprays on the bonnet aren't spaced evenly .... so after much measuring ..... checking ..remeasuring and checking attached is photo of fitted scoop.

I've only just cut away enough metal as necessary for the scoop to sit in the bonnet ..... and has two slots as the back of the scoop has a plastic flange that also
recesses into bonnet taken measurements.

I had concern's about pressurizing under the bonnet and my thoughts is that I can cut away more metal if necessary for larger slot for increased air flow if necessary.

I checked an old post back on this site in 2016 when I first voiced my concerns on heat from transmission tunnel.
I'd purchased a digital thermometer and had taken readings from the bell housing and gearbox .... readings where 74 deg C

Took it for a run to Bunnings today ...... normal operating temperature and about 33 Degrees in Perth.
Temperature inside cabin driving ... transmission reading 42 deg at radio and 38 deg at transmission tunnel.

Engine temperature (dashboard gauge only) still sitting on just below halfway mark as always.

I'll keep monitoring it but very happy with outcome and I don't think the scoop has detracted from the vehicle.

I've plans to respray the bonnet and cowling in front of windscreen so that it will be the same colour for now it does not look out of place.

Baggy

[blackrangie]

Mould is done, will be off the shelf soon.

Should look awesome when painted same colour as car, time will tell what a difference it makes.https://www.aulro.com/afvb/images/imported/2018/01/835.jpghttps://www.aulro.com/afvb/images/imported/2018/01/836.jpg

[gavinwibrow]

I saw Tombie scoop .... looks like its off a Toyota hilux and its achieved (OK no scientific evidence) what I'm aiming for.
I've been toying with this for a while ....so I've bitten the bullet and picked up a S/Hand GU Patrol (2010) bonnet scoop today ... and its white [smilebigeye]

I'll start fitting it tomorrow ..... worst case scenario ....... I'll need a new bonnet.

cheers

Baggy

Good thinking, and I'm watching with much interest for my RRC - and possibly application for my D2, even though different to the D1 thread.

Worst case scenario - I have a green 93 RRC bonnet in my collection with your name on it waiting for you - maybe initially even use that for the trials rather than your white one? Don't recall any under bonnet dam on my wreck either though.
Cheers Gavin

PS, I'll probably get howled down, but didn't notice much change when DazzaTD5 took my driving lights off for a heat trial about a year ago, and I would have put any change down to removing the waterbra mesh that was also fitted at the time. Roll on the Saudi grill!!

[blackrangie]

Hi All,

Things to note on a GU Patrol scoop ..... The're not evenly shaped and add to this that a Rangie bonnet (ribs underneath) are not spaced evenly.

The washer sprays on the bonnet aren't spaced evenly .... so after much measuring ..... checking ..remeasuring and checking attached is photo of fitted scoop.

I've only just cut away enough metal as necessary for the scoop to sit in the bonnet ..... and has two slots as the back of the scoop has a plastic flange that also
recesses into bonnet taken measurements.

I had concern's about pressurizing under the bonnet and my thoughts is that I can cut away more metal if necessary for larger slot for increased air flow if necessary.

I checked an old post back on this site in 2016 when I first voiced my concerns on heat from transmission tunnel.
I'd purchased a digital thermometer and had taken readings from the bell housing and gearbox .... readings where 74 deg C

Took it for a run to Bunnings today ...... normal operating temperature and about 33 Degrees in Perth.
Temperature inside cabin driving ... transmission reading 42 deg at radio and 38 deg at transmission tunnel.

Engine temperature (dashboard gauge only) still sitting on just below halfway mark as always.

I'll keep monitoring it but very happy with outcome and I don't think the scoop has detracted from the vehicle.

I've plans to respray the bonnet and cowling in front of windscreen so that it will be the same colour for now it does not look out of place.

BaggyAny 110kph results?

What speed was this test?

[DoubleChevron]

Any 110kph results?

What speed was this test?

Tests while towing :confused: ie: heavy heat load as well please :)

There has been all sorts of stuff tried to cool the underbonnet area of a citroen DS (the real one, not the modern lumps of plastic excrement)... The later the cars with more stuff under the bonnet, the hotter they run. The radiator size and quality seems to make little difference... neither do vents/scoops. Someone worked out the issue was the ability for air to exit the underbonnet area. On the later cars, add in underbonnet heat shielding, extra plumbing, bigger engines ... more heat. but less space behind the engine to allow the pressurised air entering the underbonnet area .... to exit.

I wonder if that is where we start running into problems.... the ability to allow the heated air to vent from the underbonnet area ?

seeya,
Shane L.

[Davo]

That's it exactly, getting the air out, not in. I had educate myself in this through countless hours of reading but once I realised this, then it all became easier.

The internet is swamped by threads where guys plop a scoop on a bonnet because it "looks right", and then these threads always end with something about how it "seems to work". There's very, very little showing how someone worked it out for themselves properly. One of the best threads I found had hidden in it a couple of comments from a guy with a big racing car in America, where he'd used some aftermarket radiator intake kit that rammed more air in but only pressurised the engine bay. He got rid of it and improved the engine bay air exit and it made a huge difference for him. (And this was at something like 150mph!)

That giant scoop shown above isn't going to work because it's going to allow air through the bonnet, when you want it going through the radiator. It [I]might[I] work if all that air goes straight down the back of the engine bay and creates a low pressure area behind the radiator, but because of the amount of stuff in the way and the enormous turbulence it will cause, it won't be that straightforward. More likely is that the air tries to get into the radiator, and tries to get into the engine bay through the scoop, and the poor radiator will be stuck in the middle with not enough airflow. You can get away with a lot of this when the ambient temperature is only 20c or 25c, but as you point out it all changes with an extreme heat load, towing, and so on.

[DoubleChevron]

That's it exactly, getting the air out, not in. I had educate myself in this through countless hours of reading but once I realised this, then it all became easier.

The internet is swamped by threads where guys plop a scoop on a bonnet because it "looks right", and then these threads always end with something about how it "seems to work". There's very, very little showing how someone worked it out for themselves properly. One of the best threads I found had hidden in it a couple of comments from a guy with a big racing car in America, where he'd used some aftermarket radiator intake kit that rammed more air in but only pressurised the engine bay. He got rid of it and improved the engine bay air exit and it made a huge difference for him. (And this was at something like 150mph!)

That giant scoop shown above isn't going to work because it's going to allow air through the bonnet, when you want it going through the radiator. It [I]might[I] work if all that air goes straight down the back of the engine bay and creates a low pressure area behind the radiator, but because of the amount of stuff in the way and the enormous turbulence it will cause, it won't be that straightforward. More likely is that the air tries to get into the radiator, and tries to get into the engine bay through the scoop, and the poor radiator will be stuck in the middle with not enough airflow. You can get away with a lot of this when the ambient temperature is only 20c or 25c, but as you point out it all changes with an extreme heat load, towing, and so on.

that was my thinking too. as it's a big scoop. In slow moving traffic I reckon it'll work well.... as the air will exit from there. at speed it'll make a high pressure zone in the engine bay ... infact if the pressure in the engine bay is close the pressure of the air entering the radiator. the radiator will have zero cooling air flow...........................

seeya,
Shane L.

[Baggy]

Hi All,

Gavin - Thanks for the offer and you are what this site is about ... great people who offer to assist where necessary [bigsmile1]
Hoping that I don't need your bonnet as I believe the GU Patrol scoop is the right balance .... its not too big.

Reading through the treads with input from Davo .... Shane and others (Thank you) my thoughts was the following.

I only cut way enough bonnet to allow the scoop to drop into position in the front.

If you look straight at the scoop opening .... my bonnet runs just below halfway through the opening of the scoop so air is split halfway flowing down the slot in the front
with the rest flowing further down the scoop into a small slot cut in the rear for a fin that runs across the back of scoop.

I cut a groove just wide enough to allow the fin (with a bit of pushing with a screwdriver) to allow it to drop in and to sit in position.

When I took it for a spin I took it up the Row highway (100 Kms) ..... 33 degree day ... got to normal operating temperature and drove fine .... in fact it
maybe wishful thinking on my part but seemed more responsive and kicked down better .... no scientific evidence and only a short run.

With the slots I was more concerned that with the airflow it would becoming this large white whistle ..... thankfully no.
My reasoning's for going minimal were the advice on pressurization ... and not to hinder the radiator .... again I have no temperature issues with this vehicle.

You can always enlarge the slots if necessary not vice versa.

I took the temperature inside cab while driving at only 70 Kms per hour .... got home while engine running checked transmission bell housing temperature and pan
from underneath vehicle with digital thermometer.

IMO ...the large bonnet scoop does fill the opening on a classic bonnet but I'm unsure how practical it will be as others have already stated.

The jury is still out for me ...... I'll drive it over the next coming months and see if there is any noticeable difference in heat from the transmission tunnel which was the reason
for this exercise.

Hoping that I don't need to contact Gavin for a bonnet ....... [bigsmile1]


Cheers

Baggy

[DiscoMick]

I don't understand aerodynamics, but I was thinking that aircraft wings are shaped to cause air to flow over the top, so that causes the air under the wing to lift up, causing the wing to lift.
So if the aim is to get hot air out of the engine bay, then a bonnet should be shaped like a wing so the outside air flows over the top, while the hot air underneath is drawn up and out the rear of the scoop.
That would also cause air to be drawn thru the radiator and then up and out the rear.
Does that sound right?

[Baggy]

Hi All,

Here's a thought ..... looking at that large bonnet scoop for the classic from blackrangie.

If it was reversed (open at the rear) could that as others suggested on the Disco 1 forum page give a low pressure area to draw in air rather than
ramming air in from the front?

Cheers

Baggy

[Baggy]

Discomick - I like you am unsure.

The biggest difference to me would be the air flowing over a wing is not restricted.

Unfortunately under the bonnet of all cars is an area never designed for air flow efficiently except in the more exclusive marques who have
the computer modelling technology / wind tunnel for such things and where this may matter at higher speeds.

I on the other hand will have to grab my blower vac and a smoker to see if I can see where the air goes [biggrin]

cheers

Baggy

[blackrangie]

That's it exactly, getting the air out, not in. I had educate myself in this through countless hours of reading but once I realised this, then it all became easier.

The internet is swamped by threads where guys plop a scoop on a bonnet because it "looks right", and then these threads always end with something about how it "seems to work". There's very, very little showing how someone worked it out for themselves properly. One of the best threads I found had hidden in it a couple of comments from a guy with a big racing car in America, where he'd used some aftermarket radiator intake kit that rammed more air in but only pressurised the engine bay. He got rid of it and improved the engine bay air exit and it made a huge difference for him. (And this was at something like 150mph!)

That giant scoop shown above isn't going to work because it's going to allow air through the bonnet, when you want it going through the radiator. It [I]might[I] work if all that air goes straight down the back of the engine bay and creates a low pressure area behind the radiator, but because of the amount of stuff in the way and the enormous turbulence it will cause, it won't be that straightforward. More likely is that the air tries to get into the radiator, and tries to get into the engine bay through the scoop, and the poor radiator will be stuck in the middle with not enough airflow. You can get away with a lot of this when the ambient temperature is only 20c or 25c, but as you point out it all changes with an extreme heat load, towing, and so on.You say it wont and it might work in the same comment.

The scenerio where you say it "might work" is exactly what has been posted above as what is intended.

As nobody has ever to my knowledge tried a scoop like this on a RRC it will be a learnig experience for everyone.

The aim is to make 2 holes at back of scoop to direct air down the firewall and each side of engine and out.

Back half of inner wheel arc removed

Bonnet side rears vented.

If it doesnt work it will be blanked off and probsbly stay if it enhances the look of the car [emoji41]

[blackrangie]

Hi All,

Gavin - Thanks for the offer and you are what this site is about ... great people who offer to assist where necessary [bigsmile1]
Hoping that I don't need your bonnet as I believe the GU Patrol scoop is the right balance .... its not too big.

Reading through the treads with input from Davo .... Shane and others (Thank you) my thoughts was the following.

I only cut way enough bonnet to allow the scoop to drop into position in the front.

If you look straight at the scoop opening .... my bonnet runs just below halfway through the opening of the scoop so air is split halfway flowing down the slot in the front
with the rest flowing further down the scoop into a small slot cut in the rear for a fin that runs across the back of scoop.

I cut a groove just wide enough to allow the fin (with a bit of pushing with a screwdriver) to allow it to drop in and to sit in position.

When I took it for a spin I took it up the Row highway (100 Kms) ..... 33 degree day ... got to normal operating temperature and drove fine .... in fact it
maybe wishful thinking on my part but seemed more responsive and kicked down better .... no scientific evidence and only a short run.

With the slots I was more concerned that with the airflow it would becoming this large white whistle ..... thankfully no.
My reasoning's for going minimal were the advice on pressurization ... and not to hinder the radiator .... again I have no temperature issues with this vehicle.

You can always enlarge the slots if necessary not vice versa.

I took the temperature inside cab while driving at only 70 Kms per hour .... got home while engine running checked transmission bell housing temperature and pan
from underneath vehicle with digital thermometer.

IMO ...the large bonnet scoop does fill the opening on a classic bonnet but I'm unsure how practical it will be as others have already stated.

The jury is still out for me ...... I'll drive it over the next coming months and see if there is any noticeable difference in heat from the transmission tunnel which was the reason
for this exercise.

Hoping that I don't need to contact Gavin for a bonnet ....... [bigsmile1]


Cheers

BaggyThe scoop is just a scoop, its what holes are cut under it and where that count.

[blackrangie]

I don't understand aerodynamics, but I was thinking that aircraft wings are shaped to cause air to flow over the top, so that causes the air under the wing to lift up, causing the wing to lift.
So if the aim is to get hot air out of the engine bay, then a bonnet should be shaped like a wing so the outside air flows over the top, while the hot air underneath is drawn up and out the rear of the scoop.
That would also cause air to be drawn thru the radiator and then up and out the rear.
Does that sound right?Yes on bonnet sides, but cant really do legally on bonnet tops due to hot air hitting windscreen and fogging and if oil hose bursts at speed your stuffed for vision etc

[blackrangie]

Hi All,

Here's a thought ..... looking at that large bonnet scoop for the classic from blackrangie.

If it was reversed (open at the rear) could that as others suggested on the Disco 1 forum page give a low pressure area to draw in air rather than
ramming air in from the front?

Cheers

BaggyNot legal from what i hear. Remember the million v8 79series cruisers and patrols etc etc out there we all see with these kind of big scoops, yes the air goes through an intercooler, but it still has to exit somewhere. From what i know these cars are not experiencing overheating issues.

[DiscoMick]

Yes on bonnet sides, but cant really do legally on bonnet tops due to hot air hitting windscreen and fogging and if oil hose bursts at speed your stuffed for vision etc
I guess that's why there are so many aftermarket vents for the sides of the mudguards back just before the firewall, to exhaust air out the sides, not onto the windscreen.

[Davo]

I don't understand aerodynamics, but I was thinking that aircraft wings are shaped to cause air to flow over the top, so that causes the air under the wing to lift up, causing the wing to lift.
So if the aim is to get hot air out of the engine bay, then a bonnet should be shaped like a wing so the outside air flows over the top, while the hot air underneath is drawn up and out the rear of the scoop.
That would also cause air to be drawn thru the radiator and then up and out the rear.
Does that sound right?

Yes, that is about right, but then you'll find, (as I certainly did!), that once you change one thing, everything changes. That's why car aerodynamics has so much written about it.

[Davo]

Hi All,

Here's a thought ..... looking at that large bonnet scoop for the classic from blackrangie.

If it was reversed (open at the rear) could that as others suggested on the Disco 1 forum page give a low pressure area to draw in air rather than
ramming air in from the front?

Cheers

Baggy

If the engine bay is a low pressure area like mine, then yes, that's what would happen. But remember I've got a sort of air dam under the bullbar bumper and a rubber seal between the bonnet and body.

[Davo]

Discomick - I like you am unsure.

The biggest difference to me would be the air flowing over a wing is not restricted.

Unfortunately under the bonnet of all cars is an area never designed for air flow efficiently except in the more exclusive marques who have
the computer modelling technology / wind tunnel for such things and where this may matter at higher speeds.

I on the other hand will have to grab my blower vac and a smoker to see if I can see where the air goes [biggrin]

cheers

Baggy

I've got a pedestal fan, incense sticks, and some of that liquid smoke stuff you use for smoke machines! [tonguewink] I soaked some cotton wool and heated it with a soldering iron. Primitive, yes, but being able to see air flow is what it's all about. I'm still scheming how to build a wind tunnel . . . until some common sense cuts in.

[Davo]

You say it wont and it might work in the same comment.

The scenerio where you say it "might work" is exactly what has been posted above as what is intended.

As nobody has ever to my knowledge tried a scoop like this on a RRC it will be a learnig experience for everyone.

The aim is to make 2 holes at back of scoop to direct air down the firewall and each side of engine and out.

Back half of inner wheel arc removed

Bonnet side rears vented.

If it doesnt work it will be blanked off and probsbly stay if it enhances the look of the car [emoji41]

Alright, keep your pants on, the "won't work" comment is based on some actual knowledge and the "might work" comment is based on guesswork. You could well get a good result but it depends completely on that low pressure working as you want it to, which means everything has to be just right, which - and believe me, I've spent a few years on this - takes about equal parts research and luck! Unfortunately to measure these changes it takes a lot of finicky work which most of us just don't have the resources for.

And yes, someone else has done something similar with a Range Rover and they reckoned it worked. Of course, it looks cool anyway.

[blackrangie]

Alright, keep your pants on, the "won't work" comment is based on some actual knowledge and the "might work" comment is based on guesswork. You could well get a good result but it depends completely on that low pressure working as you want it to, which means everything has to be just right, which - and believe me, I've spent a few years on this - takes about equal parts research and luck! Unfortunately to measure these changes it takes a lot of finicky work which most of us just don't have the resources for.

And yes, someone else has done something similar with a Range Rover and they reckoned it worked. Of course, it looks cool anyway.Who has and have you got photos?

[Davo]

Sorry, I don't know who, it was just someone on here from a thread I saw a few years ago. Their scoop was smaller, though. That's my concern with what you're doing - the scoop is too big. The secret is to have a big low pressure area and a small, high pressure intake. Of course, like everyone else, I just assumed that ramming air in would do the job, (which appears to make sense at first), until I figured this out.

[DiscoMick]

https://www.aulro.com/afvb/images/imported/2018/01/877.jpg
A Puma Defender's bonnet has a nice bulge in it to clear the engine, so you'd think the air would rush nicely over the top, creating a low pressure area underneath at the rear, ripe for a vent.

[blackrangie]

Sorry, I don't know who, it was just someone on here from a thread I saw a few years ago. Their scoop was smaller, though. That's my concern with what you're doing - the scoop is too big. The secret is to have a big low pressure area and a small, high pressure intake. Of course, like everyone else, I just assumed that ramming air in would do the job, (which appears to make sense at first), until I figured this out.So you dont know anybody thats done it like this [emoji6]

[blackrangie]

https://www.aulro.com/afvb/images/imported/2018/01/877.jpg
A Puma Defender's bonnet has a nice bulge in it to clear the engine, so you'd think the air would rush nicely over the top, creating a low pressure area underneath at the rear, ripe for a vent.Bonnet sides maybe on defender, rear facing is not legal and will fog up windscreen middle

[Davo]

https://www.aulro.com/afvb/images/imported/2018/01/877.jpg
A Puma Defender's bonnet has a nice bulge in it to clear the engine, so you'd think the air would rush nicely over the top, creating a low pressure area underneath at the rear, ripe for a vent.

Nope, that's a high pressure area where the air meets the bottom of the windscreen. Also, you might find, as I accidentally did, that there's enough low pressure in the engine bay to suck air in the vent.

[Davo]

So you dont know anybody thats done it like this [emoji6]

I did find a few things on the internet over the last several years with various front-facing scoops but no, not absolutely exactly with a whacking big bird-eating scoop like yours - as far as I can remember, anyway. So, once yours is done, if you really want to know if it works, you'll need a Magnehelic gauge to see what it's doing.

[Davo]

Five minutes later . . . here you go:

Defender :: 1994 Land Rover Defender 90 - Defender Source (http://www.defendersource.com/forum/f61/defender-1994-land-rover-defender-90-a-54294.html)

What do you think? - Land Rover Forums - Land Rover Enthusiast Forum (https://landroverforums.com/forum/discovery-ii-18/what-do-you-think-31042/)

Range Rover Convertible (http://www.rangerovers.net/forum/7-range-rover-mark-ii-p38/172-range-rover-convertible.html)

https://www.masai4x4.com/Masai-Sport-Bonnet-Scoop-for-Land-Rover-Defender-GRP-p63776034

Range Rover Tuning Hood Scoop - Land Rover Forums - Land Rover Enthusiast Forum (https://landroverforums.com/forum/range-rover-19/range-rover-tuning-hood-scoop-59435/)

[blackrangie]

I did find a few things on the internet over the last several years with various front-facing scoops but no, not absolutely exactly with a whacking big bird-eating scoop like yours - as far as I can remember, anyway. So, once yours is done, if you really want to know if it works, you'll need a Magnehelic gauge to see what it's doing.Ive never seen anything even remotely close on the internet or on the street of forward facing bonnet scoops on Range Rover Classics or Discoverys other than the one i recently posted made by the same guy.

This style is starting to get popular on defenders, examples online can be foind pretty quickly. And a few newer rangies have addes them.

As far as whacking bird eating big, its actually almost the most slimline you could get, try saying that to every 79series driver you meet in person, see how many whacks you get haha.

Agreed with testing, however temps on the freeway, idle and heat soak reduction will be my first tests

[blackrangie]

Five minutes later . . . here you go:

Defender :: 1994 Land Rover Defender 90 - Defender Source (http://www.defendersource.com/forum/f61/defender-1994-land-rover-defender-90-a-54294.html)

What do you think? - Land Rover Forums - Land Rover Enthusiast Forum (https://landroverforums.com/forum/discovery-ii-18/what-do-you-think-31042/)

Range Rover Convertible (http://www.rangerovers.net/forum/7-range-rover-mark-ii-p38/172-range-rover-convertible.html)

https://www.masai4x4.com/Masai-Sport-Bonnet-Scoop-for-Land-Rover-Defender-GRP-p63776034

Range Rover Tuning Hood Scoop - Land Rover Forums - Land Rover Enthusiast Forum (https://landroverforums.com/forum/range-rover-19/range-rover-tuning-hood-scoop-59435/)None of these are RRC, and is there data on these links showing it doesnt work?

Only 2 links work and one is not about scoops

[blackrangie]

My point is show me where someone has added a good sized wide forward facing scoop and it has not worked on a defender, discovery or RRC

I can find almost zero on RRC, plenty of people have done this to discos and defenders and newer rangies, and im sure there would be horror story's to be found pretty quick if it was not to work

Here are the ones with bird gobblers I have found to date.[emoji6]https://www.aulro.com/afvb/images/imported/2018/01/889.jpghttps://www.aulro.com/afvb/images/imported/2018/01/890.jpghttps://www.aulro.com/afvb/images/imported/2018/01/891.jpghttps://www.aulro.com/afvb/images/imported/2018/01/892.jpghttps://www.aulro.com/afvb/images/imported/2018/01/893.jpghttps://www.aulro.com/afvb/images/imported/2018/01/894.jpghttps://www.aulro.com/afvb/images/imported/2018/01/895.jpghttps://www.aulro.com/afvb/images/imported/2018/01/896.jpghttps://www.aulro.com/afvb/images/imported/2018/01/897.jpg

[blackrangie]

Here is a disco from the guy the built minehttps://www.aulro.com/afvb/images/imported/2018/01/898.jpghttps://www.aulro.com/afvb/images/imported/2018/01/899.jpghttps://www.aulro.com/afvb/images/imported/2018/01/900.jpg

[Davo]

Dear God, there's always one on these forums. Picky picky picky. If you want that kind of detailed information, go find it yourself or do some tests. You haven't seen this information yet because it's the internet, not a science magazine, and most people never do proper testing, and certainly rarely start a thread about their latest modification only to admit later it didn't work. Which is why bonnet scoop threads usually end with, "It seems to work well." (Gold Star exception: that Autospeed site where what'sisname does things properly.)

My point is that the idea is nothing new, and that it won't work without really good engine bay venting, and proving it works means having the gauge and getting the numbers. Also, things like giant whale shark mouth-stylee scoops aren't going to cause big problems in a mild climate where a radiator is usually happy. You can get away with a lot down south. If you really want to test it, you need to live up here where the weather is either hot, very hot, or mostly hot. That's when interfering with radiator airflow shows up.

But now that you've raised the bar with your expectations, please get that gauge, do the science, and report back. Thank you.

Good luck with it and have fun.

[DiscoMick]

Here is a disco from the guy the built minehttps://www.aulro.com/afvb/images/imported/2018/01/898.jpghttps://www.aulro.com/afvb/images/imported/2018/01/899.jpghttps://www.aulro.com/afvb/images/imported/2018/01/900.jpg
That's a nice looking scoop, but it's behind the radiator, so it's not pushing air through the radiator. Instead it's pushing air in to the rear of the engine. That would affect air pressure in the rear of the engine bay. How would it help to draw air through the radiator, or to vent hot air from the rear of the engine? Isn't the aim to have high pressure on the radiator and low pressure behind it to draw air through, or have I got this all wrong? Just trying to understand.

[blackrangie]

Dear God, there's always one on these forums. Picky picky picky. If you want that kind of detailed information, go find it yourself or do some tests. You haven't seen this information yet because it's the internet, not a science magazine, and most people never do proper testing, and certainly rarely start a thread about their latest modification only to admit later it didn't work. Which is why bonnet scoop threads usually end with, "It seems to work well." (Gold Star exception: that Autospeed site where what'sisname does things properly.)

My point is that the idea is nothing new, and that it won't work without really good engine bay venting, and proving it works means having the gauge and getting the numbers. Also, things like giant whale shark mouth-stylee scoops aren't going to cause big problems in a mild climate where a radiator is usually happy. You can get away with a lot down south. If you really want to test it, you need to live up here where the weather is either hot, very hot, or mostly hot. That's when interfering with radiator airflow shows up.

But now that you've raised the bar with your expectations, please get that gauge, do the science, and report back. Thank you.

Good luck with it and have fun.When one resorts to name calling and slander, they have already lost the debate. [emoji6]

[blackrangie]

That's a nice looking scoop, but it's behind the radiator, so it's not pushing air through the radiator. Instead it's pushing air in to the rear of the engine. That would affect air pressure in the rear of the engine bay. How would it help to draw air through the radiator, or to vent hot air from the rear of the engine? Isn't the aim to have high pressure on the radiator and low pressure behind it to draw engine through, or have I got this all wrong? Just trying to understand.Agreed, its good looking.

Aim is to reduce engine bay heat and thus heat soak both at speed, idle and when engine is off.

Lets move over to this thread thats on the same subject and this and other questions have been discussed.

Will a bonnet scoop reduce heat in the engine bay? (https://www.aulro.com/afvb/discovery-1-a/257694-will-bonnet-scoop-reduce-heat-engine-bay.html)

[Davo]

That's a nice looking scoop, but it's behind the radiator, so it's not pushing air through the radiator. Instead it's pushing air in to the rear of the engine. That would affect air pressure in the rear of the engine bay. How would it help to draw air through the radiator, or to vent hot air from the rear of the engine? Isn't the aim to have high pressure on the radiator and low pressure behind it to draw air through, or have I got this all wrong? Just trying to understand.

Yes, you've got it, and that's the point I have been so laboriously trying to explain here. You would need to do lots of testing or be very lucky to have it work at speed, creating a low pressure at the back of the engine bay. But it is damn sexy.

[Davo]

When one resorts to name calling and slander, they have already lost the debate. [emoji6]

Now that's funny. You just go ahead and point out where that's happened.

If only you put this much effort into understanding airflow, then we'd have a real discussion! Now, like I said, prove your scoop works instead of boarding the AULRO express train, destination: The Bottom of the Debating Barrel, regular daily service. I'd be happy to be wrong, but with aerodynamics you need proof other than the butt dyno we all usually rely on.

[blackrangie]

Now that's funny. You just go ahead and point out where that's happened.

If only you put this much effort into understanding airflow, then we'd have a real discussion! Now, like I said, prove your scoop works instead of boarding the AULRO express train, destination: The Bottom of the Debating Barrel, regular daily service. I'd be happy to be wrong, but with aerodynamics you need proof other than the butt dyno we all usually rely on.Again on the attack [emoji6]

[gavinwibrow]

Again on the attack [emoji6]


Gentlemen - you both have good if not excellent contributions to make on this issue, with lots of interest in the outcome/s from the sidelines.
Join forces and conquer the world!!! [bigsmile]

[blackrangie]

Gentlemen - you both have good if not excellent contributions to make on this issue, with lots of interest in the outcome/s from the sidelines.
Join forces and conquer the world!!! [bigsmile]Whilst i agree, I dont respond to personal attacks, simple.

There is another thread going that has covered all this and more and seems pretty civil so lets keep it all there in one place [emoji41]

[gavinwibrow]

Whilst i agree, I dont respond to personal attacks, simple.

There is another thread going that has covered all this and more and seems pretty civil so lets keep it all there in one place [emoji41]



Yep, been following all threads with real interest hoping to have an outcome for both of my steeds for when they get hot towing big loads. Onwards and upwards we go

[Baggy]

Hi All,

Blackrangie - Appreciate the extra information you supplied on positions of holes in bonnet to direct air down the sides
and rear of engine bay and removal of rear wheel arches as a means of evacuating air out of engine bay.

Look forward to any results you can give in the future.

I also can see Davo's point of view in that in the Disco 1 post many have mentioned that improved (directed) airflow
through the radiator is the only way to cool an engine and where's he's from where 40 degree is a pleasant day and
alterations like mine could for example come back and bite you badly in the middle of nowhere.

As Gavin has said both you have a shared interest at heart ....

On further driving of my Rangie yesterday the only scientific evidence I can give is the same as Tombie .... My radio used to get
extremely hot to touch ...in fact I'd shy away from putting CD's on a long drive ...... afraid they would get stuck in the unit.

Shane - Double Chevron could probably throw light on the heat required to warp a CD ... he's pretty good on obscure facts [smilebigeye]

Now my radio is warm to touch ..... but nothing Id concern myself with.

Also .... put it down to dumb luck the positioning of my scoop the front airflow is over the plentinum chamber and the rear slot towards the back
of the firewall ..... no smoke test done (I was actually joking in an earlier post) ... However she seems far more responsive in acceleration.

I might just use Davo's method to produce smoke as a test ..... better still ... I'll wait till he builds a wind tunnel ... drive up (hopefully Rangie doesn't overheat) and use it.

Finally ...... I could have "Go Fast Bonnet Scoop" syndrome which I hear is very contagious .... or my other thought is that cooling the plentinum chamber
the air into the cylinder is now cooler and has improved fuel burning ...... HOW'S THAT'S FOR OPENING A NEW CAN OF WORMS"

This is where I insert "the disclaimer" I'm an untrained professional please do not try this at home yourself [biggrin]


Cheers

Baggy

[Davo]

Again on the attack [emoji6]

I see you can't differentiate between an actual personal attack, (name-calling, questioning parental genetics, etc.) and a sarcastic request for evidence which you keep managing to avoid presenting, so I'll make it simple.

You say your scoop will work. Then show us how. As simple as that.

I say it won't, because I've done a lot of research and I've managed to learn one or two things along the way. One of those things was that you can't just shove air into a radiator or an engine bay. I know because I tried it. Like most of the things I tried! So, considering you've put more effort into responding to me than researching what I've bothered to try and explain to you, go on and do that research. Prove me wrong - and I'll put a big scoop on too!

Now the onus is on you to provide that proof - anything else is just squeaking on the internet.

[Davo]

Hi All,

Blackrangie - Appreciate the extra information you supplied on positions of holes in bonnet to direct air down the sides
and rear of engine bay and removal of rear wheel arches as a means of evacuating air out of engine bay.

Look forward to any results you can give in the future.

I also can see Davo's point of view in that in the Disco 1 post many have mentioned that improved (directed) airflow
through the radiator is the only way to cool an engine and where's he's from where 40 degree is a pleasant day and
alterations like mine could for example come back and bite you badly in the middle of nowhere.

As Gavin has said both you have a shared interest at heart ....

On further driving of my Rangie yesterday the only scientific evidence I can give is the same as Tombie .... My radio used to get
extremely hot to touch ...in fact I'd shy away from putting CD's on a long drive ...... afraid they would get stuck in the unit.

Shane - Double Chevron could probably throw light on the heat required to warp a CD ... he's pretty good on obscure facts [smilebigeye]

Now my radio is warm to touch ..... but nothing Id concern myself with.

Also .... put it down to dumb luck the positioning of my scoop the front airflow is over the plentinum chamber and the rear slot towards the back
of the firewall ..... no smoke test done (I was actually joking in an earlier post) ... However she seems far more responsive in acceleration.

I might just use Davo's method to produce smoke as a test ..... better still ... I'll wait till he builds a wind tunnel ... drive up (hopefully Rangie doesn't overheat) and use it.

Finally ...... I could have "Go Fast Bonnet Scoop" syndrome which I hear is very contagious .... or my other thought is that cooling the plentinum chamber
the air into the cylinder is now cooler and has improved fuel burning ...... HOW'S THAT'S FOR OPENING A NEW CAN OF WORMS"

This is where I insert "the disclaimer" I'm an untrained professional please do not try this at home yourself [biggrin]


Cheers

Baggy

Does your Rangie have the CD player down in front of the gear shifter? If that's the case, then you may well have managed to get the air down along the back of the engine and along the bulkhead, which wouldn't be a bad thing. But as you say so correctly, it's all guesswork, which is the crux of the problem. (I should know - I've made a lot of bad guesses on this subject!)

Now if you really want to cool that plenum, you'll need an intercooler . . . oh no, I've gone cross-eyed . . .

But seriously, I'd recommend some sort of fan and an incense stick, just to see. It's amazing what odd things air will do that you couldn't imagine.

[RaZz0R]

wow ...

if you take a step back for a minute - and really look at it and think about it...

Who seriously gives a flying frack if it works or not? Does it look cool? Yes! Can it be functional? Yes!

Altho it does make one wonder what would happen with water coming over the bonnet?
But I like the look of the scoop that Blackrangie has put on his. I am thinking Bitsy might look good with it on as well.
Functional or not :)

[blackrangie]

I see you can't differentiate between an actual personal attack, (name-calling, questioning parental genetics, etc.) and a sarcastic request for evidence which you keep managing to avoid presenting, so I'll make it simple.

You say your scoop will work. Then show us how. As simple as that.

I say it won't, because I've done a lot of research and I've managed to learn one or two things along the way. One of those things was that you can't just shove air into a radiator or an engine bay. I know because I tried it. Like most of the things I tried! So, considering you've put more effort into responding to me than researching what I've bothered to try and explain to you, go on and do that research. Prove me wrong - and I'll put a big scoop on too!

Now the onus is on you to provide that proof - anything else is just squeaking on the internet.Again on the attack [emoji6]

[Homestar]

Ok, enough is enough with the back and forth here please - we get that there's differing views here, please keep it civil guys.

Personally I think a forward facing vent at speed would help push the hot air out from under the bonnet down below the engine. Yes, testing would be good, but I think anything would help to be honest.

[blackrangie]

Ok, enough is enough with the back and forth here please - we get that there's differing views here, please keep it civil guys.

Personally I think a forward facing vent at speed would help push the hot air out from under the bonnet down below the engine. Yes, testing would be good, but I think anything would help to be honest.Agreed

[Mick_Marsh]

I don't understand aerodynamics, but I was thinking that aircraft wings are shaped to cause air to flow over the top, so that causes the air under the wing to lift up, causing the wing to lift.
So if the aim is to get hot air out of the engine bay, then a bonnet should be shaped like a wing so the outside air flows over the top, while the hot air underneath is drawn up and out the rear of the scoop.
That would also cause air to be drawn thru the radiator and then up and out the rear.
Does that sound right?
No.

Think more like a venturi. he faster the air is flowing, the less pressure. So, if you have air flowing over a bonnet, it is at a lower pressure than the air under the bonnet that isn't moving. If you drill a hole in the bonnet, the air under the bonnet will move through that hole to the lower pressure area above the bonnet where the air is moving.
But, for a car, you need to take into account the high pressure area caused by the windscreen.
Lots of fluid modelling involved.

[DoubleChevron]

Again on the attack [emoji6]

??? This is just plain bizarre. If someone doesn't agree with you ... It does not mean they are attacking you. Everyone has an opinion ... That's fine with me.

This is what I mean .... when I try stuff... I'll say blunty "well **** .... that didn't work and cost me a lot of time and money". with regards to melting CD's. I must have what is one of the hottest cars ever made to travel in ( crappy ventilation and way to much glass area). So when I tried to verify that any changes I made actually worked. I finally found at one change that did help heat soak:

citroen cx insulation (http://www.shanescitshed.com/cx2500/air-con/citroen_cx_insulation.html)

The guy that makes the stuff liked my findings so linked them to his website:

EZ Cool Automotive Insulation heat barrier and noise reduction for cars, trucks, classic cars, street rods and much more (http://www.lobucrod.com/)

I have also obviously used the same stuff on the floors, firewall and transmission tunnel of my Rangie ..... You know, towing in heat, the transmission tunnel still gets bloody warm. I'll have to figure a way of laying more insulation over the gearboxes big rubber gasket.

In your case. I'd pick a day like tomorrow (38degrees).... hook up the caravan or loaded car trailer ... and go for a 20km drive out of town down one of the quiet roads and record the temperatures the car runs at. Then block the bonnet vent and do the same 20km drive and see what the differences are.... Then do the same thing through town. I'm pretty sure you will find an improvement in temperatures sitting in traffic. But towing at speed it really going to suck big time.

seeya,
Shane L.

[blackrangie]

Actually when someone attacks you by calling you names etc its a personal attack, a difference in opinion is fine.

[blackrangie]

Honestly this thread is pointless there is allready one on this very subject as mentioned above that covers all this and more...i wont be posting on this thread in future.

Will a bonnet scoop reduce heat in the engine bay? (https://r.tapatalk.com/shareLink?url=https%3A%2F%2Fwww%2Eaulro%2Ecom%2Faf vb%2Fshowthread%2Ephp%3Ft%3D257694&share_tid=257694&share_fid=669&share_type=t)

Will a bonnet scoop reduce heat in the engine bay?

[Baggy]

Hi Blackrangie

I appreciate you advising me of the post on disco 1 forum.

I started the post as I drive a RRC and have had this heat from transmission since I purchased her in early 2016 and refer my post in this classic section.

I don't drive a Disco so don't visit that forum page on this site ( no disrespect to Disco owners) and was non the wiser of its existence.

My 2cents worth the biggest problem with responses to posts is that you cannot tell the tone or the feelings you get compared with direct conversation with someone.

For myself ...in emails where I endeavour to keep them short they may come over terse or in a manner that may be taken the wrong way when I've reread them ...just ask my boss :)

That's why imogies (think that's the correct term) was invented to assist with this.

Your choice to make any further post but will keep an eye on Disco 1 forum page for updates.

Shane - I do remember you mentioning that matting for heat ...and appreciate you input in posts.

Cheers

Baggy

[Baggy]

Hi RaZzor,

I do agree the scoop of Blackrangie does look good on the Disco and on the Rangie bonnet if it was just for cosmetic purposes with no holes in your bonnet.

Where we all agree to disagree is if it will do the intended job without creating further issues and the jurys out on both sides of that fence.

If you cut a hole into your bonnet you raise a valid point on water egress into your engine bay be it by rain or by a water crossing and how you would deal with that.

For me the GU scoop was the choice as it's not too large and I've kept the hole into my bonnet as minimal as possible to avoid pressurization of the engine bay which is the hot issue (excuse the pun) on this post

I've had similar results to Tombie ... Although non scientific but happy with results so far.

I'm hoping water egress will not be an issue but will have to wait till winter for that test and deal with it then


Cheers

Baggy

[grey_ghost]

Hi all, an add popped up on Facebook this morning- a guy on Geelong selling his supercharged 350 chev, currently in a RRC... Notice the interesting multiple vents...135426

[DiscoMick]

Nice looking Rangie.

So the vent at the rear would let hot air out and rain in. The venting of the hot air would cause a low pressure area and more air would be sucked through the radiator.

A forward facing scoop would have forced air and rain into the rear bulkhead area. That would raise the air pressure near the bulkhead and reduce flow through the radiator.
Is that right?

[Mick_Marsh]

Nice looking Rangie.

So the vent at the rear would let hot air out and rain in. The venting of the hot air would cause a low pressure area and more air would be sucked through the radiator.

A forward facing scoop would have forced air and rain into the rear bulkhead area. That would raise the air pressure near the bulkhead and reduce flow through the radiator.
Is that right?

No. A reverse bonnet air scoop has it's opening in an area of higher pressure not lower pressure. You need to do the fluid modelling to determine if what you say is correct or not.

Before you put holes in the bonnet, you need to work out what you are trying to achieve. Some people put a forward bonnet scoop in their bonnet to reduce engine bay temperature. Some do this because they want air flow through an intercooler. Some do this because they want an increase in power. There is power loss because the carburettors have to suck harder and power loss from the less dense hot air. By adding a cold air intake above the radiator of my Commodore, the motor gained an extra 3kW.

Reducing engine bay temperature and increasing air flow through the radiator is not necessarily the same thing.
I have posted up a picture of a P38 with a forward bonnet air scoop. The owner had issues with the engine running hot. Installing the air scoop reduced the engine bay temperature and solved his hot engine problems.

[DoubleChevron]

Hi all, an add popped up on Facebook this morning- a guy on Geelong selling his supercharged 350 chev, currently in a RRC... Notice the interesting multiple vents...135426


That looks like it's had a huge amount of time and effort gone into it. I think the bulge .... is a bulge not a scoop that opens it to the engine bay ? (to clear the supercharger ? ). The side vents should work really well to clear underbonnet air in traffic I imagine ... I doubt they would effect cooling at speed ( I really don't know, but I don't think that is a high pressure area there ... if it's low pressure, it's only going to do good things ... ie: help exhaust hot air from the underbonnet area at any speed and under all conditions).

seeya
Shane L.

[uninformed]

Not all scopes are doing the same thing

are you trying to ram air in the intake, cool an intercooler, or remove hot air from the engine bay.

Pick that first, then go to your craft shop, buy some wool and some sticky tape and do some wool pile testing at various speeds before you even think about adding or cutting

unless its just for the cool/**** factor, then have at it.

Dont discount the engineers that designed these vehicles in the first place.

Who really wants a forward facing scoop on a 4x4??

[RaZz0R]

Hi RaZzor,

I do agree the scoop of Blackrangie does look good on the Disco and on the Rangie bonnet if it was just for cosmetic purposes with no holes in your bonnet.

Where we all agree to disagree is if it will do the intended job without creating further issues and the jurys out on both sides of that fence.

If you cut a hole into your bonnet you raise a valid point on water egress into your engine bay be it by rain or by a water crossing and how you would deal with that.

For me the GU scoop was the choice as it's not too large and I've kept the hole into my bonnet as minimal as possible to avoid pressurization of the engine bay which is the hot issue (excuse the pun) on this post

I've had similar results to Tombie ... Although non scientific but happy with results so far.

I'm hoping water egress will not be an issue but will have to wait till winter for that test and deal with it then


Cheers

Baggy

I was just surprised at the .. personal attack vs diff of opinion etc.

Truth be told - when I had me Greenie with the 4.6lt and extractors - I had extended the rubber stops of the bonnet to help vent out that extra heat.
It helped a little, but with extractors that are not heat wrapped you are going to get a hot engine bay. Just the way it is. Wrapping the headers will help move that heat along out of the engine bay.
Would probly do more than a scoop would just with that.

I understand people wanting to go in to the details of design aspects and if a scoop would work or not - in the end trying it out is really the only way to tell.
As with all our 4x4 gear tho there are pros and cons.

Hence why - if it looks good and the person doing it likes it and is going to give it ago - who really cares? :)

[Baggy]

Hi All,

grey_ghost - Thanks for picture ...... that's one nice looking 2 dr classic.
I do like those side vents .... I wonder what its off and where he got them from?
Could you supply a link on facebook.... I've searched for it but couldn't find it although that could be my lousy internet skills.

RaZzOR - As you said you make a decision ... try something and deal with the consequences either good or bad .... least you've tried.
Same fo my bonnet scoop .... I'm monitoring it and will learn from this exercise.

Shane /Mick-Marsh / DiscoMick / uninformed - From what I've gleaned on this discussion and both forum pages is that a rear facing scoop with a low pressure (at the rear) and side vents
(similar to grey_ghosts photo) may assist the radiator in cooling an engine BUT one should do some test / homework before proceeding.

Also ... do the basics checks first ... if your engine getting hot check the radiator (get it rodded and cleaned - professionally) look at thermostat, water pump, hoses, check for leaks and use a good coolant.
Check there's nothing restricting the flow of air from spotties and lightbars before looking at a bonnet scoop.

If there's additional engine bay heat due to add on's ..extractors etc ... a forward facing scoop (like mine) where the issue is not for cooling the engine but to move hot air out of the engine bay may provide
some success (this seems to be the case for me .... my opinion only)

I'll keep monitoring it,

Cheers

Baggy

[grey_ghost]

Hi Baggy, I found it!! (after searching for about 30 minutes!)

HMLR (Heavily Modified Land Rovers) public group | Facebook (https://www.facebook.com/groups/191986491154791/permalink/563103607376409/)

The FB group is called Heavily Modified Land Rovers....

Cheers,
GG

[DoubleChevron]

I'm pretty sure the base of the windscreen/scuttle is a very high pressure zone. That is why the ventilation intakes are almost always there :)

seeya,
Shane L.

[Davo]

??? This is just plain bizarre. If someone doesn't agree with you ... It does not mean they are attacking you. Everyone has an opinion ... That's fine with me.

This is what I mean .... when I try stuff... I'll say blunty "well **** .... that didn't work and cost me a lot of time and money". with regards to melting CD's. I must have what is one of the hottest cars ever made to travel in ( crappy ventilation and way to much glass area). So when I tried to verify that any changes I made actually worked. I finally found at one change that did help heat soak:

citroen cx insulation (http://www.shanescitshed.com/cx2500/air-con/citroen_cx_insulation.html)

The guy that makes the stuff liked my findings so linked them to his website:

EZ Cool Automotive Insulation heat barrier and noise reduction for cars, trucks, classic cars, street rods and much more (http://www.lobucrod.com/)

I have also obviously used the same stuff on the floors, firewall and transmission tunnel of my Rangie ..... You know, towing in heat, the transmission tunnel still gets bloody warm. I'll have to figure a way of laying more insulation over the gearboxes big rubber gasket.

In your case. I'd pick a day like tomorrow (38degrees).... hook up the caravan or loaded car trailer ... and go for a 20km drive out of town down one of the quiet roads and record the temperatures the car runs at. Then block the bonnet vent and do the same 20km drive and see what the differences are.... Then do the same thing through town. I'm pretty sure you will find an improvement in temperatures sitting in traffic. But towing at speed it really going to suck big time.

seeya,
Shane L.

You're right there, Shane. Standard Issue AULRO discussion deterioration, complete with moderator not quite understanding the point. The only reason I'm still on this pub-argument-styled forum is because I can't be bothered putting together my own website!

You're also right in the post above. Where the airflow over the bonnet meets the windscreen is high pressure and there's no point trying to extract air out of the engine bay there. Anyway, in response to a lovely PM from someone the other day, I will attempt to finally get around to putting together a thread on this hilariously confusing subject.

[DiscoMick]

You're right there, Shane. Standard Issue AULRO discussion deterioration, complete with moderator not quite understanding the point. The only reason I'm still on this pub-argument-styled forum is because I can't be bothered putting together my own website!

You're also right in the post above. Where the airflow over the bonnet meets the windscreen is high pressure and there's no point trying to extract air out of the engine bay there. Anyway, in response to a lovely PM from someone the other day, I will attempt to finally get around to putting together a thread on this hilariously confusing subject.
So, say if I'm wrong, are you saying there is a high pressure area above and outside the bonnet, at the base of the windscreen, and so hot air from inside the engine bay would be restricted from exiting through a vent at the rear of the bonnet? Interesting.
That may be why Rangies have their vents on the sides of their mudguards instead.
And I take Mick's point that a forward-facing scoop may be useful to push air into a top-mounted intercooler. However LRs use front intercoolers instead, to avoid the hot air at the top of the engine.
It's all interesting. I've learnt a lot on this thread. Thanks to all.

[Davo]

Yes, yes, and yes again. I know this because I've done so much reading, so it's not just an opinion, it's a fact which can be backed up. Very important with aerodynamics.

I tried posting a picture a few days ago to help with this, so I'll try again:

135486

And even though it's a modern design, the basic principles still apply.

[gavinwibrow]

Yes, yes, and yes again. I know this because I've done so much reading, so it's not just an opinion, it's a fact which can be backed up. Very important with aerodynamics.

I tried posting a picture a few days ago to help with this, so I'll try again:

135486

And even though it's a modern design, the basic principles still apply.

SoDavo, from one of the many that hope you will stay and continue to pass on words of wisdom - a thought from left field.

I haven't got my beastie around to check, but is there room anywhere in the bottom of the rear front mudguards of an RRC to mount exhaust fans, possibly even with venting to attract/exhaust from up near the rear of the bonnet?

The other thought, which properly belongs in the other generic thread, is the airflow differences arising from TD5 as opposed to V8?
Of course just to be different, I have a TD5 in my RRC anyway.[bighmmm]
Cheers

[PLR]

G`day , its got some pics and basic understanding of where air goes is not temperature specific .

Page 2 and 3 are best probably but the scoop is an intake scoop not what is discussed here it does suggest what goes on at the sides .






Car Aerodynamics Basics, How-To & Design Tips ~ FREE! (http://www.buildyourownracecar.com/race-car-aerodynamics-basics-and-design/)

[Davo]

SoDavo, from one of the many that hope you will stay and continue to pass on words of wisdom - a thought from left field.

I haven't got my beastie around to check, but is there room anywhere in the bottom of the rear front mudguards of an RRC to mount exhaust fans, possibly even with venting to attract/exhaust from up near the rear of the bonnet?

The other thought, which properly belongs in the other generic thread, is the airflow differences arising from TD5 as opposed to V8?
Of course just to be different, I have a TD5 in my RRC anyway.[bighmmm]
Cheers

Well, that venting is what you want to have, but without needing fans. The whole idea is to set up the engine bay so that the airflow does it for you. You need to find or create some low pressure areas. Either way, you need to measure this low pressure, and that means either getting the gauge I mentioned earlier, or just a piece of clear hose - one end in the engine bay, and one end with you inside. You put a U at your end and fill it with some coloured water, and the more that water moves up towards the engine bay, the lower that pressure is. Then, moving the other end around the engine bay will give you some idea of what's really happening under there.

The interesting thing about the Range Rover engine bay is that a Holden or Ford from about the same time has so much room around the motor that you could see the ground, so there's plenty of room for airflow. The Rangie, on the other hand, has a short, wide bonnet which makes seeing over it very easy when off-road, but there's not much room for airflow, and that's why I've been trying to improve it. Which I'll have to get back too soon.

[Davo]

G`day , its got some pics and basic understanding of where air goes is not temperature specific .

Page 2 and 3 are best probably but the scoop is an intake scoop not what is discussed here it does suggest what goes on at the sides .






Car Aerodynamics Basics, How-To & Design Tips ~ FREE! (http://www.buildyourownracecar.com/race-car-aerodynamics-basics-and-design/)

Hey, get out of here with yer learnin'! [biggrin] Thanks for the link. That's the kind of thing people need to read to get a start on this. There is so much really good information out there these days that this biggest problem is wading through it all.

[DiscoMick]

That was an interesting link.

One question I do have after reading it is whether fitting underbody protection such as a steering guard and bash plates for the transfer, transmission and fuel tank would interfere with the venturi effect in which careful design can cause a low pressure area to occur under the vehicle, increasing down force.
While down force isn't important on a 4WD, and the designers may not give it much consideration, it is important for cooling to have a low pressure area rear of the radiator so air is drawn through it from the high pressure area ahead of the radiator, as air naturally flows from high to a low pressure area, trying to equalise the pressure.
So, would underbody protection plates interfere with the air flow? Would cooling efficiency be reduced, or even increased?
I have no idea. Any thoughts?

[Davo]

With the whole car, you'd never know without a wind tunnel or an enormous amount of measuring, point-by-point, under the car. However, in the engine bay you could just do what I was describing before with a long hose, one end in the car, one end where you want to measure, and do comparisons that way.

I've put a flat bit of metal from under the bullbar bumper to a steering guard, (the factory type, which is a big bit of pipe: NRC7009 - just so you can picture it), and sealed up the bonnet. I know I'm getting low pressure because of it, but haven't had the chance to measure it yet.

Interestingly, that factory fitted a plastic thing under the front of the engine bay on some '90s models, MWC6937, which is referred to as a "cooling tray", (or something like that), in some factory books. I think it was used in conjunction with that plastic front spoiler under the bumper, but I still haven't worked out what it was supposed to do. I'm going to make something similar and see what happens - I've got to do the measurements as above first, though.

[DiscoMick]

Yes, it's certainly just guesswork without a wind tunnel.
I had assumed steering guards should have lots of holes to let plenty of air blow through, but now I'm wondering if that is right.
I doubt if the designers of underbody protection for 4WDs think much about aerodynamics.

[PLR]

The wording in the box under the blue Subaru may be of interest .

Seems the important part is not getting air in .

Tells a bit about pressure in the engine bay .






AutoSpeed - Undertrays, Spoilers & Bonnet Vents, Part 1 (http://www.autospeed.com/cms/article.html?&title=Undertrays-Spoilers-Bonnet-Vents-Part-1&A=113176)

[PLR]

Hey, get out of here with yer learnin'! [biggrin] Thanks for the link. That's the kind of thing people need to read to get a start on this. There is so much really good information out there these days that this biggest problem is wading through it all.


G`day ,

yea , learnings good i learn lots new just wish i had the capacity to retain in detail .


Your Pub Forum comment made me smile but then i thought there are plenty of people that read only on the forum and a lot of those have information to contribute but because of how things do happen they don`t .

It has always amused me when someone says i`m going or not taking about the subject any more . If your not involved how can you contribute or change things .

[Davo]

The wording in the box under the blue Subaru may be of interest .

Seems the important part is not getting air in .

Tells a bit about pressure in the engine bay .






AutoSpeed - Undertrays, Spoilers & Bonnet Vents, Part 1 (http://www.autospeed.com/cms/article.html?&title=Undertrays-Spoilers-Bonnet-Vents-Part-1&A=113176)

Thanks for that link, too. Yes, I did appear to have some slight difficulties in getting this exact point across recently. [bigwhistle] Autospeed is excellent and is where I really started to actually learn about this stuff, instead of just guessing. Then I found reports and technical sites and have kept trying to learn.

[Davo]

G`day ,

yea , learnings good i learn lots new just wish i had the capacity to retain in detail .


Your Pub Forum comment made me smile but then i thought there are plenty of people that read only on the forum and a lot of those have information to contribute but because of how things do happen they don`t .

It has always amused me when someone says i`m going or not taking about the subject any more . If your not involved how can you contribute or change things .

I think that's become a big problem here, but during a discussion last year others didn't agree because, apparently, the number of members are up. But I joined this forum because the technical stuff was so good, and now it seems that some of the ridiculous infighting in areas like General Chat put a lot of good people off. I've found some of the moderation when this happens to be a bit lacklustre, to say the least.

[PLR]

I think that's become a big problem here, but during a discussion last year others didn't agree because, apparently, the number of members are up. But I joined this forum because the technical stuff was so good, and now it seems that some of the ridiculous infighting in areas like General Chat put a lot of good people off. I've found some of the moderation when this happens to be a bit lacklustre, to say the least.


It`s good i guess that i`m of a similar mind .

I`ve asked questions and made suggestions about nonexistent concerns . Discussion there was none there needs to be a problem . It`s related the forum goes against the trend with new members but if you look at the members list there are many dormant non financial . The number of hits on a subject or area is the gauge .

The slowing of new posts and new posters seems real but is my preconception .

To my wonderment during one of my presuming i had some sort of entitlement to think about what i thought could improve the forum ( which i was shown i don`t ) i was asked if i was alright .

None of this is of course helpful and will receive the naysayers label but at least nowdays the dogs are only puppys .

I apologise for putting this in what i once considered sacred ground ( too much ? ) but it has also been related that nowdays anything can go anywhere and does it matter .

[Pedro_The_Swift]

. I've found some of the moderation when this happens to be a bit lacklustre, to say the least.

I'm sorry you feel this way Davo,,
If the Moderation is not up to scratch Please REPORT the offending remarks,,
failing that, please email Incisor.

[Davo]

I'm sorry you feel this way Davo,,
If the Moderation is not up to scratch Please REPORT the offending remarks,,
failing that, please email Incisor.

It's been mentioned in a thread or two, particularly one thread from last year, but nobody seems to get it. It's not a matter of reporting offending remarks, it's when a moderator doesn't even understand a problem in the first place and blunders their way to an answer which suits them but doesn't actually address anything. I doubt that's something that's going to improve unless we have some moderators to moderate the moderators. [bighmmm]

[incisor]

It's been mentioned in a thread or two, particularly one thread from last year, but nobody seems to get it. It's not a matter of reporting offending remarks, it's when a moderator doesn't even understand a problem in the first place and blunders their way to an answer which suits them but doesn't actually address anything. I doubt that's something that's going to improve unless we have some moderators to moderate the moderators. [bighmmm]

a single moderator rarely if ever does anything off their own bat UNLESS it is considered extremely urgent and even then they must report the post(s) in question so a copy of the original exists for the records.

when a post is reported it is acted on after getting a consensus.

some get reinstated, some burned and some altered depending on the consensus gained.

moderators that don't follow the guidelines don't usually last long.

dammed sure no one is ever going to please 20k+ people all the time, but we do try our best to get it right, whether those affected think so or not.

[Davo]

Oh, I understand what you're saying Dave, no argument there, and it doesn't work too badly. And you may remember I've mentioned this sort of thing once or twice in the past. What's frustrating is when, as in this instance, a member like blackrangie tries to twist a discussion into something personal instead of just sticking to the original point, and then instead of being told to behave a moderator bumbles in with this:


Ok, enough is enough with the back and forth here please - we get that there's differing views here, please keep it civil guys.

Personally I think a forward facing vent at speed would help push the hot air out from under the bonnet down below the engine. Yes, testing would be good, but I think anything would help to be honest.

essentially agreeing with him, which just makes me bang my head on the keyboard. I've just spent more time than it appears to be worth trying to explain why it wouldn't work, and . . . why did I bother, exactly?

And how many times does this happen when there is a discussion that goes out of control because of one or two members? And what happens? The good people give up and leave, the loudmouths stay on, and too often when I've told people about this forum it turns out that its reputation has preceded it, which is enough to put them off. Over the last decade I've had this happen quite a few times.

As for me, why should I stay? I have almost three decades of Land-Rover DIY and enough knowledge to help a few people, but there's always that one guy with the big mouth who can't stick to the point. Why should I bother participating when these guys aren't told to shut up and manage to ruin quite a few good threads?

[DiscoMick]

Stick around Davo, I've learned a lot from your posts.
As someone who has run foul of the mods a few times myself, and didn't always agree with them, I still say they are trying hard to do a good job and should be given credit for their voluntary efforts. Just chill. It's all good in the long run.

On the original topic, looking back at the green Disco below, it's front looks almost identical to what ours did, with two big Light force spotties blocking the grille.
I didn't realize how much airflow was blocked until I had to remove them when our electric fans failed up the Cape. Without the lights, we were able to get enough airflow to drive back to Brisbane while running the air con and not overheat.
So I reckon if the green Disco had the big lights removed it may not need a bonnet scoop. My theory.

https://www.aulro.com/afvb/images/imported/2018/01/1058.jpg

[incisor]

Oh, I understand what you're saying Dave, no argument there, and it doesn't work too badly. And you may remember I've mentioned this sort of thing once or twice in the past. What's frustrating is when, as in this instance, a member like blackrangie tries to twist a discussion into something personal instead of just sticking to the original point, and then instead of being told to behave a moderator bumbles in with this:



essentially agreeing with him, which just makes me bang my head on the keyboard. I've just spent more time than it appears to be worth trying to explain why it wouldn't work, and . . . why did I bother, exactly?

frustrates the crap out of me as well, but that is the nature of publlic discussions.

from the days of LTAUE on fidonet to modern day forums and realtime social media, only the speed at which it occurrs has changed IMHO

to be frank, that is the post you should have reported if you felt it crossed a line.

one of the guidelines in the mods pen is that you should not directly moderate a thread you are involved in.

sometimes the lines are blurred and you don't see it till you look back.

it isnt an easy task to be frank....

PS EDIT:

Homestar was not on the moderatiing staff when making those comments, he resigned a while ago for reasons of his own, so not bound by the rules governing mods...

[Homestar]

Oh, I understand what you're saying Dave, no argument there, and it doesn't work too badly. And you may remember I've mentioned this sort of thing once or twice in the past. What's frustrating is when, as in this instance, a member like blackrangie tries to twist a discussion into something personal instead of just sticking to the original point, and then instead of being told to behave a moderator bumbles in with this:



essentially agreeing with him, which just makes me bang my head on the keyboard. I've just spent more time than it appears to be worth trying to explain why it wouldn't work, and . . . why did I bother, exactly?

And how many times does this happen when there is a discussion that goes out of control because of one or two members? And what happens? The good people give up and leave, the loudmouths stay on, and too often when I've told people about this forum it turns out that its reputation has preceded it, which is enough to put them off. Over the last decade I've had this happen quite a few times.

As for me, why should I stay? I have almost three decades of Land-Rover DIY and enough knowledge to help a few people, but there's always that one guy with the big mouth who can't stick to the point. Why should I bother participating when these guys aren't told to shut up and manage to ruin quite a few good threads?

As Inc said, I'm not a mod any more - couldn't commit the time required at the moment so thought it best to remove myself. Most here wouldn't know how much time, effort and dedication it takes to assist in running this place but there's always those that critisise what is done by the volunteers here all too easily IMO - It can be a VERY tough job. And I don't see what this has to do with anything anyway? Am I the first person to voice my opinion here? But you choose to single me out? Does it matter if I agree with you or not? No one here listens to a thing I say about power systems or generators and that's what I've been doing for a living most of my life, so hey that's the way it is sometimes.

I personally don't think you need to get a bee in your bonnet about it that's for sure. If any offence has been caused by me voicing an opinion, I do sincerly appologise. You might be right, and have done more research than me - that's cool, but don't make it personal like this, it really isn't warranted IMO.

And again, that's MY OPINION - just as valid as any others here - right or wrong. I'm happy to leave it at that, no offence really caused, I'm just a bit perplexed by it all is all.