Thread: Bonnet scoop on RRC

I have this on mine.
There is actually a thread running at the moment on bonnet scoops and vents etc...

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.

Originally Posted by Davo

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.

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

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

Originally Posted by gavinwibrow

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! But I'll try and get to it soon.

Originally Posted by 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

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 . . . )

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

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

cheers

Baggy

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