Stuart Knight

iTrader: (2)

Car is MY94 WRX, with STiV heads, Cosworth pistons, and Scoobysport 2.5" turbo back catless exhaust, ported heads, standard TD05, but I am about to change that to front entry, 550 injectors, PACE FMIC, Blitz Induction kit, Power Engineering remap.

Question is which headers are going to help spool up? I don't want a set of screamers with everything up the top end. Also who would you recomend to custom re-map the standard ECU, I really don't need the expense of going down the Link/GEMS/Motec route if I can get away with it.

milo

a lot of people report none or negative gains with headers. someone on here however (sorry - cant remember who) reported a 25bhp+ gain with gruppe-s headers... they're cheap too.

i dunno if you'll get much more gains than just the standard headers ported tho.

with regards to ecu... your spec says u have a power engineering remap... logically if u want it remapped, why not go back to them?

nice spec on your car btw.

Stuart Knight

iTrader: (2)

Milo,

Thanks for your response. I have always been happy with PE work regards mapping, but Mervyn is with ECUTEK now, so not sure if I can get him to still work on mine. If I can, great, if not I need some alternatives! I must ring him and see what he says.

As regards the headers there seems to be a bit of a problem with the Gruppe S ones, and I really don't need any more grief at the moment.

Thanks for the comments on the spec, she does drive very well, and on Saturday at G-force pulled 325.5bhp and 300lb/ft on the rollers. Peak torque arrived late at 5000rpm though, and peak boost was only 1.1bar with 1 bar held. Great figures for the boost, but I think there may be a leak in my headers as last time the peak torque slipped from 4000 to 5000 rpm it was the collector that had failed. If I have to replace that again I would rather go for some new headers and up-pipe.

Stuart

Fangoria

iTrader: (1)

Gruppe S suck big time (for the 50% that have the problems with them!!)

25bhp gain - no chance......... maybe an increase in torque lower down but 25bhp - Thats like putting on a larger Turbo.... though I guess depends on the amount of restriction the headers are causing in the 1st place. I reckon the gain I got between the Gruppe S and ported headers was maybe about 5 bhp/5lbs

I wish I'd kept the standard ported headers on. Maybe the HKS ones arent bad afterall if they dont have leaking issues!?

[Edited by Fangoria - 1/26/2004 4:05:25 PM]

milo

what about the gains u had when porting the standard headers? what do u reckon they were over standard?

what would scooby do

..also where's the best place to "drive in - drive out" i.e. get the headers removed, ported and refitted in one day ??

thanks in advance..

sonu

Fangoria

that's interesting. What problems have people had with Gruppe-S headers?

Thanks

Sonu

Fangoria

iTrader: (1)

Gains with ported headers

Dont exactly as I had a fully decated exhaust fitted at the same time

I got 25bhp!! with a less restrictive exhaust and ported headers - I already had a BPM system with a sports cat - but moved to a HKS Hyper and Hatward and scott downpipe. I didnt see much of a torque increase!

I reckon that the benefits were maybe 10 bhp for the headers and 15 for the exhaust

Of course they werent done back to back so depends on rollers and from one day to the next plus minor mapping tweaks

I doubt there are very few people that will go in get the headers off, file them and put them back on in a day

It takes about 4/5 hours of dull labour to smooth them down and circa 3/4 hrs to take them off and put back on again - if you hav the originals you'd want to remove the metal crap on the outside and wrap them instead.......

I just sold a set of original sti headers (ported) for £70 - so you could have had mine maybe - but no-one looks at a bargain!

Depends where your going with the power - less than 400bhp you can probably get away with porting the originals - over this you'll want external ones - and NOT Gruppe S - or if you do make sure the Flanges are machined before you have them fitted!!

nom

The Gruppe-S are 'interesting', fitting-wise. In short, many of them didn't.

I've used standard headers (noisy & seem to do the same job as sticking a load of treacle in the engine, although have a suprisingly good torque spread), HKS headers (raise spool by around 300rpm, and really come on-song at around 4,200rpm where the improvement over standard is impressive), and MRT ones (now unavailable, look like spiders legs, actually seem to lower the spool-point over standard, and flow approximately the same as the HKS ones).
Both aftermarket headers are a marked improvement over the standard ones, although the improvement was minimal when I tried the HKS with a TD04 (but there's an obvious improvement starting from something similar to a TD05). Also, I have never had a problem with later spool points, only lag, and the HKS ones only reduce that marginally (the MRT ones improve it).
Shame the MRT ones aren't available any more...

Maddog

Strong statement, that one...

You have experience of *many* headers to justify the comment? Hmm..didn't think so.

AlanG

I didn't think they were that bad to fit at all and that was the solid pipe versions.

You do have to check the support bracket though when fitting, but people don't and don't tell their fitter either!, that's where the problem comes in with fitting.

Alan

GBruce

Hi,

I have just fitted equal length headers to my uk98. Seems a bit worse low down but improved mid to top end power allthough this hasn't been tested on a dyno. They are a 4 into 2 design with 1.5" pipes.

Have lost a lot of the flat 4 rumble and i'm still not sure I like this.

Good luck

George

Fangoria

iTrader: (1)

Maddog

Yeah maybe a little bit too Harsh - must have been in one of those moods again!!!

They clearly have made a noticeable difference with the Turbo

I have seen other Headers and am aware of problems other people have had with them - I know the HKS Headers and have seen in detail the OBX ones - but not tried either.......

I think that if Gruppe S sorted out the flanges and some of the design issues.....so you didnt have to mess about filing and adjusting the up-pipe bracket they would be top notch.......

They cost me £329 plus a few sundry bits - they are 90% very good - exceptional build quality its just the other bits that let them down - just a few tweaks and they would be the best - how can you argue with the price - I guess Its just I have now spend double the price in time/money with little effect except blowing headers time after time...... will try one more time taking account of the brackets......if they go again - then I will have to contemplate exactly what to change them to - Ion maybe?

Maddog

Are Ion and Gruppe-S not a similar design with only minor differences?

never seen Ion myself.

harvey

iTrader: (48)

Ion and Gruppe 'S' are virtually the same. At the imported price from the U.S. it makes sense to go for Gruppe 'S'. Have them fitted properly. Courtesy of Jonny Gav I have a thicker header to up-pipe gasket which is more like a spacer and with proper fitting that has solved the problem I think.
Ported O/E headers will show a measurable difference if done properly. It is not just a lick over with a file to extract maximum gains. Just ask Rich Wild.
Going from ported O/E to Ion headers I got 22bhp.
The choice of header and up-pipe is very important and what works well on a big turbo, big exhaust, big power car may not work on a car with a TD04 for instance where a smaller diameter header and up-pipe may be preferable.

[Edited by harvey - 1/27/2004 5:50:52 AM]

DeanF

iTrader: (1)

I have fitted Gruppes headers & up-pipe on my 94 Uk Turbo, They did blow at first as did many others from where the collector flange bolts to the up-pipe, I have now fitted 1 composite gasket & 1 solid, Seems to have cured it, Previous R&R gave 275.5 Bhp & 269 Torq, after headers 310 Bhp & 271 torque, so well chuffed, Pulls much stronger right to the limiter, although peak torque has moved up 500 Rpm's

Dean

nom

Something to remember that Harvey just touched on - the matching of the header to other bits of kit. This is really quite critical. E.g. the equal length that PE market (can't remember which design it's based on - sorry!) works very well indeed with the TD04, but is pretty pants with anything else. I believe the HKS headers to be very good all-rounders, which is why do many other designs seem to be based on them (or even virtually identical copies), but they only work well on turbos which have most of their power over the 4,200rpm that the headers like. Which rather knocks out the tiddly turbos like the TD04.
There does seem to be a little bit of a lack of non-high-end headers around, presumably because they aren't so good at 'peak power' so don't market well - who knows?

T-uk

gruppe-s are cheap but that is about the only good point IMO.

fitted the solid up-pipe "big bore" set to john banks 2.33litre engine and they leaked at the collector. they where then removed and fitted to my car, this time paying attention to the upper brackets and they leaked, refitted with 2x ford transit(?) gaskets, back to back and they where fine. the only issue I had then(after mapping) was loss of low down torque, especially in the lower gears, so ordered through the group buy, the gruppe-s flexi up-pipe "small bore" set. these have a smaller collector/up-pipe design.

these arrived and the up-pipe looked crap compared to the rest of the finish. flexi joint looked poor for flow and welds questionable , so I fitted a GGR solid up-pipe. this was fitted with a standard subaru up-pipe/collector gasket and to date have not leaked at the collector, however the slip joints between the heads leak when cold. this set do not seem to breath as well, higher up the revs but the bottom end has improved so I can live with them.

the big bore set where then refitted to john banks second 2.33 engine, this time they sealed fine. unfortunately the engine did not work, so the car had to go south and get another 2.36 engine fitted before coming back with a STI 2.5litre US block. this came back and a week later the collector started leaking. john stripped them and found a single gasket fitted so doubled them up again but they have started leaking again when cold.

we are not sure what the situation with the upper, up-pipe brackets is on this latest engine, so we may have to remove the turbo for a look.

Stuart Knight

iTrader: (2)

Some very interesting debate here, but does anybody have an answer to the original question? What would be the best set of headers to go with my TD05 (front entry by then) so I don't lose my bottom end torque, or am I searching for something which doesn't exist. I am not worried about top end power, but as it looks like I've got replace my standard collector (again) then I am looking to get a new manifold and up pipe.

DeanF

iTrader: (1)

Stuart, I think you are just going to have to resign yourself to a little Loss of low down torque, with aftermarket headers as T-Uk says you could use a smaller bore up-pipe, but because they flow much better they will have an affect low down the range..
The TD05 Seems well suited to headers after much research on here, I have one on mine

Dean

Stuart Knight

iTrader: (2)

OK, I'm convinced. I have access to an engineer with machining tools right next to the garage so there shouldn't be too much of a problem getting them to fit. If I am going to get the front entry mod for my TD05, how much would it cost to get a TD05/06 hybrid instead? Also, where can I buy a set of GruppeS headers from and some heat wrap?

Andy.F

Stuart

If your priority is torque then stick with the TD05 front entry, std ported headers and a solid uppipe such as a H&S.
The TD05/06-20G will allow more power, especially with tubular headers but unless you are targetting over 350 then this is not necessary.

Andy

Stuart Knight

iTrader: (2)

Andy

I'm running 325bhp/300lb/ft at the moment, and although more power would be nice I am little concerned as to what will happen with the gearbox if I tweak it much more! So I think I'll take your advice, go for the new up-pipe, and get the std. headers ported. Any suggestions as to what to do if std. collecter is buggered, which I think it may be, although I haven't looked yet, its just displaying the same symptoms as when it went before, peak torque now delivered at 5000 rather than 4000, and peak boost is struggling to get to 1.1 bar, though it is mapped for 1.3

Andy.F

What was knackered on the original collector ? This is a cast piece and I have never known them to fail

Stuart Knight

iTrader: (2)

Maybe it wasn't the collecter then, from memory it was the flexy joint behind the collecter.

Andy.F

The only flexy joint behind the collector is in the uppipe, if you change that for a rigid one then the problem is eliminated

harvey

iTrader: (48)

Hi Andy: I think Stu is referring to the flexi in the cross over pipe from #2 and 4 cylinders prior to the collector. They can leak on older cars especially those that have had exposure to salt water.

harvey

iTrader: (48)

I have a Hayward and Scott up-pipe and another from Canada in the garage. I can e-mail you photos and relevant dimensions if you are interested.

dowser

Hi Harvey - which Canadian flavoured one do you have, with or without flexi? If flexi, is it still in one piece?

Richard

Stuart Knight

iTrader: (2)

Harvey,

I think thats the flex pipe I meant! Mind you it might pe a hole in the FMIC causing the boost drop. Further investigation required.