Extractors?

[xstriple]

Hi Gang,
Can anyone recommend a set of exhaust extractors or even if I will get much benefit from a 3.5 in a '91 from doing this please? The engine is getting a full top-end reco and ditching the clutchfan for a thermo system. :cool:
Cheers

[blitz]

I put Geine on mine - sounds sweet not sure how much difference it made as it was done during a major rebuild so heaps of other stuff done at the same time

[SuperchargedSport]

I've got Janspeed extractors on a 4.6 in a RRC, i cant say they do much.

I wouldnt take them back off, but if i was doing it again id just put sports mufflers in it and be happy with a rumble. Especially on a 3.5 they wont do anything. Its very difficult to get power out of the rover v8s. I mean you can get more, but not enough for the money it takes. I guess thats why so many people rip it out and put a holden 5lt in.

I have had trouble recently with the twin thermo fan setup i have on it, and i took them off while i wait for a new thermo controller and put the viscous fan back on, and its definetely slower on take off. mid range is about the same. But its slower on over taking at full throttle.

I'm looking forward to putting the thermos back on....

[101RRS]

The general consensus is that extractors do little for a Rover V8 as the standard manifolds already work similar to extractors.

Garry

[400HPONGAS]

Actually its because all Rover V8's are severely "Port Choked" If you cant get anything in ,why worry about trying to get it out !!!Its as silly as fitting one of Them Later "Thor" manifolds ,total WOFTAM

[brenno]

Its as silly as fitting one of Them Later "Thor" manifolds ,total WOFTAM

I'd heard (on this forum too) that there is significant and noticeable increase in torque. Do you know differently, or have a different experience??

[400HPONGAS]

It slightly changes the torque curve , no more than original 3.9 does ,common with all tuned length runner types . You gain better by putting in the cam at 4 degrees advanced !! redo the fuel and ignition maps while your at it
1995 disco 190hp/142kw and 236lbft/320nm
2003 Disco 188hp/140kw and 250lbft/340nm @ 4750

[PhilipA]

IMHO, having fitted one, it is well worth the considerable effort.

The aim of a Thor is not outright power but to lower the torque curve. the runners on a Thor are over a metre long compared to about 25CM for a 3.9 manifold, and have a taper to give a Hemholz boost at low revs.

I have posted dyno charts many times showing a total 50% increase in "tractive effort" from about 1200 tapering to 3000 , with a 10% loss over 4000. This also includes piggyback Unichip controlling timing and fuel. This greatly improves the highway and towing performance and the car feels much more lively .

The port limitations really do not influence the fitting of the Thor as you are not looking at high revs. In any case I disagree that the inlet ports are poor on a RV8. It is the exhaust ports that are the problem, exacerbated by a very poor casting in some later engines like 3.9s.

On heads I modified I gained 7% by opening the inlet ports and removing the guide completely from the inlet port. However I had to spend many hours on raising and cleaning the exhaust ports as there was a large step where the casting met in the middle of the port immediately below the valve.
Regards Philip A
46046

[400HPONGAS]

How can you draw those conclusion from that HAND DRAWN DD printout ! No torque curve/tractive effort plot at all. No mention of which gear you in ,(back calc RPMs)what the ramp rate was and no comparison between just the manifolds ,(without Unichip and headwork)
What ? disagree that the inlet ports are poor on a RV8., well take any heads to a pressional head porter and the will laugh themselves silly !!!You ever heard of Volumetric efficicentcy ? I build engines at around 107% VE ,Those heads choke it down to 85%.The port Choke comes from The Pushrod chokes , or for those that dont understand ,its the CSA your limited to because the Pushrod holes are so close to the runners.As for that Disastrous Short turn Dump ,you must be joking !!
Unless you fit Buick 300 or Wildcat heads ,youn never make anything decent out of any Rover V8
Your graph ,shows the diffence between what and what , Unichip and no unichip perhaps ?
Why on earth show a Graph on Horsepower/KW to demonstrate some Percieved change in Torque ?
Try plotting that all again using Torque x (RPM /5252)=HP and you will see the old Hemholz theory is useless for Variable speed engines,the useable torque range becomes way to Narrow .

[101RRS]

I think you should stop stirring up people who like the Rover V8 and finish putting that radio in your D3 so I can also do it. :D

Garry

[PhilipA]

How can you draw those conclusion from that HAND DRAWN DD printout


Garry, I usually agree with a lot that you say but in this instance we are talking a RV8 not some chev engine. I and most on this forum are not interested in outright power , or we would have big lumpy cams etc etc.
Who cares about the port restrictions when in a 4WD you are interested in torque at 2000RPM.
I recall the first crossflow Falcons and indeed the 351 4V Cleveland. Monster ports but no velocity at low revs so Ford reduced the port size into alloy head and on the 351 there is a thriving business in port reduction tongues.
The graph is "hand drawn" because it is a superimposition of 4 runs at different times on the same dyno, and the "hand drawing" follows the original plots.2 of the plots are original just overlaid with a pattern so that they can be differentiated.
Could you show me some of your comparison charts to back up your assertions. I love it when I do a lot of research and then somebody comes along and says "that is all crap" without doing a thing or presenting any evidence.

Who cares about the port restrictions when in a 4WD you are interested in torque at 2000RPM.
So you reckon runner length has no effect on torque? Tell that to all the makers who put variable length manifolds on.

With regards the cam, I believe that the 3.9 cam is the same as the 3.5 cam advanced by 2 degrees, so Rover did what you suggested.

Anyway , you are diverging. The discussion was on the effects of Thor and the dyno graphs pretty clearly show what is possible.
regards Philip A

[TerryO]

Re the original question on extractors, my 3.9 D1 has a set of extractors and a decent size full exhaust and it also has a Unichip fitted.

How does it go? ...like stink in comparision to a standard one.

The Rover head might be damn useless for making good top end power compared to a decent modified SB Chev but I can't remember the last time I saw a Discovery 1 racing down a 1/4 mile drag strip.

cheers,
Terry

[banarcus]

I'll speak from first hand experience here. I have a thor 4.0 with Genie headers and a 2.5" exhaust and high flow Magnaflow cats. The difference in low down torque was noticeble as was the midrange. Was it worth it? Yes if you're sticking with the RV8.

[400HPONGAS]

Im afraid that emotional statements such as goes like stink ,and much more noticeable , all fall in the group of ,it makes more noise,ergo it must be better.With no imperical evidence , be it dyno of 1/4 mile times .
Terry0 fits a Unichip and a set of extractors and big bore exhauxt , and thinks that all the gains came from the extractors , Hardly !
PhillipA ,why do you continue to claim that some half baked Hand drawn Rolling Dyno charts ,that report Power,are suitable for showing some redistribution of TORQUE .
Got heaps of real Dyno data ,can you read it though ? Dynaflo 901 data

By the way ,what is the cost of
Unichip
Extractors
2.5 system with Magnaflows
= at least $2000 thats just the parts

[banarcus]

It was noticeable, that was all and not "much more". I can tell from the the seat of the pants with or without noise that there was more torque down low. However if I was going to stick in a better V8 later on, I wouldn't bother as the gains for extractors alone aren't worth the cost. There is nothing emotive about my post above, I was merely giving first hand experience to the OP.

For what it's worth, I'll have a set of Genies for sale in the future and so long as they renew the cats, they'll corroborate what I've just said.

[Landie333]

Im afraid that emotional statements such as goes like stink ,and much more noticeable , all fall in the group of ,it makes more noise,ergo it must be better.With no imperical evidence , be it dyno of 1/4 mile times

This. Most ass dynos are in need of calibration. Most bolt-ons and placebos. Like the guy at work who spent $500 on 2 silicone pipes and a no-name POD filter for his Mazda MPS to which his words were "it didn't really do anything, it just sounds better"

Can anyone provide simple proof of some sort change after some bolt-on. Like fuel consumption before and after?

[banarcus]

This. Most ass dynos are in need of calibration. Most bolt-ons and placebos. Like the guy at work who spent $500 on 2 silicone pipes and a no-name POD filter for his Mazda MPS to which his words were "it didn't really do anything, it just sounds better"

Can anyone provide simple proof of some sort change after some bolt-on. Like fuel consumption before and after?

About 30-50 extra kilometres per tank. I can't prove it though.

[blitz]

bit of a reality check regarding big power in landy nothing down stream with handle it in stock form if you fang it. ZF will turn to cheese along with axles cv's etc.

If you want to strengthen everything best of british to you as you have more money than I do and yes I'm somewhat jelous that you can. The trick in my opinion is to get the best out of it without spending huge money to get the last drop of power and therefore potentially stuffing something else. As my engine was stuffed I had a 4.6 put in it and I think it was worth it but it was expensive.

I was of the understanding that I was getting the thor manifold as that came with the 4.6 - wrong, i didn't get it in writing so I got all the bits off of the original 3.9 slapped on it. If I can get one and all the associated bits at the right price I will convert it. My dyno is the seat of my pants, and that tells me it all the associated stuff I have put on it has made it better and the 4.6 better again. A different question is was it worth the money I have spent on it quite honestly no but am I happy with it yes.

I drive it hard as it is my toy and get 20lt per 100k.

[TerryO]

Im afraid that emotional statements such as goes like stink ,and much more noticeable , all fall in the group of ,it makes more noise,ergo it must be better.With no imperical evidence , be it dyno of 1/4 mile times .

By the way ,what is the cost of
Unichip
Extractors
2.5 system with Magnaflows
= at least $2000 thats just the parts


Hi 400hp,

Yep I'm sure you know heaps about making engines go fast and there is no doubt having read many of your comments over time that you don't mind telling everyone else that they know bugger all when it comes to what is fast and what is not and how slow Rover engines are.

But you continue to miss out on the important point that we are talking about old 4x4's that aren't used for drag racing or any kind of racing at all. Most are used as a means of transport with the occassional off road trip for weekend playing in the dirt fun.

Do I need or want 400 hp in my D1? The answer is no to both and anyway the rest of the drive train wouldn't last ten miles without breaking into small pieces. Add to that the expence and I would guess the Chevy engine and conversion would cost four + times the value of the vehicle. So where is the relevance for your average Disco owner?

When I say mine goes like stink in comparision to a standard one that is based on seat of the pants experience having driven both. That I would imagine is what most people can judge by and best relate to. As for dyno read outs and 1/4 mile times for comparision seriously who gives a stuff when it relates to a 15 year old D1 that is used for climbing up steap slippery hills on weekends?

I actually own a motorcycle dyno for your information and it gets used for catching cheats in the motorcycle road racing series that I own and run and one thing I know from personal experience is most people who measure everything and rate importance and what the race results should be based on dyno read outs are usually not in touch with reality.

The fast guys let their race results speak for themselves and never want or need to speak about how much or how little hp their bikes make on a dyno.

As for the cost of the unichip and exhaust, well that cost me bugger all extra. I bought the D1 with those mods and plenty of others for not much more than a standard one. ...;)

cheers,
Terry

[Disco95]

Gotta agree TerryO, I have a mate with an 80 series who keeps telling me how quick his cruiser is (4.5l petrol) , and will **** on my disco. He is an ex race driver by the way so is no stranger to quick.
Like I tell him, it's not how good my car is at speed, but how good it is at slow.:D:D:D
He won't take mo on in the rough by the way:p

[justinc]

Just a little bit of info here re D2 and D1 V8's, the D2 has a very restrictive and poorly designed engine pipe from the manifolds down to the cats, the D1 has a very nicely flowing engine pipe set, no cats. It isn't the cats that are the issue, it is the stupid immediate reduction from 2 ports to 1 that causes the problem, hence extractors fitted to a D2 are a better result IMO. (Not a fan of extractors on RV8s, just saying...)


JC

[TerryO]

I don't know why he is so excited, there is nothing special about a 4.5 80 series, while a good all rounder the word that springs to mind while describing a 80 series is ...vanilla.

The one I drove was a slug and while it has nothing to do with power or driveability no six cylinder ever sounded as good as a V8 with a decent exhaust. ...:D

cheers,
Terry