Here's a question for everyone. What exhaust system, turbo and induction kit are you running and where are your peak rev ranges. Out of interest (It's headers that interest me really) mainly looking for 2l cars but it's always interesting to hear from the likes of a 2,5l

Mine is OEM Headers, all Magnex up-pipe open neck down pipe and full 3.5" de-cat sys with 3.5" round silencer. TD05/06.

the torque curve is flat from 3800-5000 and peak power is within 10bhp from 5600-7000 with the boost tailing off around 6k.

Hopefully this will give some intersting results!

Dave.

 

Depends on how it is mapped, how much boost, how much overboost, what reserve capacity the turbo has, what gear it is run in and how it is tested, as well as cams.

If you run a large turbo at low boost you will have a very flat torque curve generally.

If you run a typical turbo to nearer its capacity it will look more like a midrange thump of torque.

What are you trying to establish?

 

Yeh what?

My Torque curve rises to @4600revs peaking at 337ftlbs.
Flat till @5800revs then tails off.

May be different since top end fuel map.

Same Turbo with HKS headers Magnex up/downpipe.

Steve.

 

I was just looking for the difference between exhausts, since i wasn't happy (enough) with recent results, headers are next on the cards.

The real figure i was looking for was 'when does the turbo spool up' but also would like a bit of an idea of how the power/torque curve looks.

I puroposely tried to keep it as simple as possible (no actual figures) to avoid it turning into one of those 'flywheel/at the wheel/which rollers/which magic tree' threads which would happen quite easily here . I do see how boost/boost control and output hav an effect but wanted to stay away from that topic.

Cams don't seem to be a popular mod here, but always interesting to see the effects of different profiles. (i'm unaware of the difference in profile between UK and STI)

With enough replys it could give a good look on what matches what well.

Or i could just ask Alan G

Dave.

[Edited by RB5_245 - 1/11/2004 12:34:56 AM]

[Edited by RB5_245 - 1/11/2004 12:39:48 AM]

 

does this help - my02wrx full tsl turbo back sports cat system and powerstation headers with a ecu tek3

Graph

problem with mine is it don't hold boost past 5.2k

but a new turbo and injectors should sort this

 

Erm. Turbo spools up from 2800 reading 1 bar at 3200

Scoobysports/Janspeed Mid/back.

Send you a copy if you like???

 

On 2.0 with 20G, OEM headers and 2.5" magnex or 3" revolution it did 1 bar in 5th at 3050 RPM.

[Edited by john banks - 1/11/2004 10:21:28 AM]

 

could you e-mail it too me? as profile....

Don't think i'll spring for HKS personally though, bit too steep for my liking

John, i remember T-Uk saying your car was really laggy though with the 20G when it was a 2,0

Any theorys on this? (hijacks his own thread )

Dave.

[Edited by RB5_245 - 1/11/2004 9:16:31 PM]

 

the issue with john's was not lag as much as the tall second gear in the UK box and 7k rev limit.

stick a 20g on a UK or STI and IMO as long as both cars peak before 7k, there will never be much difference on the rollers between them, however out on the road the STI with shorter gearing and tall rev range will feel far more flexible.

I would get in touch with alang for a set of headers. he is selling a set that IMO are better than the gruppe-s.

 

Laggy by his standards he like to be able to powerslide in 2nd gear corners, and a turbo which hits at 3000 in 5th gear is never going to respond like a TD04 or TD05.

Lag is what happens when you stamp on it in the middle of the power band say after a gearchange. There was very little lag at 5000 RPM for example.

Boost threshold - eg. 1 bar at 3000 RPM in 5th gear has some correlation with lag.

The plot below compares to the most powerful and torquey TD04 plot that is available. Some later plots with the 20G did slightly better than this with even more octane booster. I don't think it was laggy, but to be fair in 2nd gear there was no real yee-ha until 4000 RPM. If you turn the boost down it feels less laggy of course because there is less on-off.



There is a slight difference at the bottom where you might not expect it - this is possibly due to the TD04 car using very conservative weight inputs to Delta Dash, or the bigger turbo making it freer low down, but you get the idea.

I've cross posted with T-uk - we are saying the same thing, it is a fine curve for a 2.0, but there is not instant response from this capacity in a low gear with UK gearing and such small capacity. The 2.5 is a completely different kettle of fish and would have P***ed off up the road long before the 2.0 spooled up.

[Edited by john banks - 1/11/2004 9:36:59 PM]

 

we swapped p20spd's exhaust from H&S to HKS Hiper.. and oh my god.. what a difference...

changed other things too so couldnt say what it did to the torque, ill let him say though.

 

I am really looking forward to see how steven finds the new box.

I think it will offer a nice spread of gears for track work,back road bashing and smaller round-a-bouts than his current gearing.

it will be interesting to see if he looses much time on the 1/4.

[Edited by T-uk - 1/11/2004 9:51:20 PM]

 

no... this was fitted about a year ago..

 

Changing from the H&S system to the HKS Hiper gave a 5bhp gain and 12lbft, with absolutely no other mods done at all. Runs were in october 2002 WL3 and May 2003 WL5.

David, T-UK is referring to the gearbox, but that wont be going in the car until the house is finished, and i probably kill the 5speed again

The graph below may help, obviously quite a lot of mods, but changes between wl3 and wl5 is from h&S system to hks hiper, and change between wl5 and wl6 is OBX headers and a new inlet pipe made up.



Steven

[Edited by P20SPD - 1/12/2004 10:42:39 AM]

 

yeah ok.. I cant read..

David

[Edited by David_Wallis - 1/12/2004 10:44:38 AM]

 

Dave

I can email you some graphs later showing different boost/torque curves.
If you want a gearbox crunching rush of midrange torque then run a TD05 at 1.8 bar If you want a progressive M3 stylee power curve with flat line torque from 4k upwards then the 06 you have is the best bet for that.
Also, as you still retain the TMIC the higher efficiency of the 20G compressor will hold gains for you due to the lower heat generation. (but you know that )

Andy

 

Actually Andy, i was a bit dissapointed with the result I got, Probably from the air flow up above 100mph by-passing the scoop???

At 130 in 4th inlet was up above 40 degrees, not too much of an issue for me as i never wanted a top speed car.

Looking at it now, for this power level i probably would have got better results with a VF35, but being to stubborn to admit that i'll just have to move up a little

Headers look like my next plan, to try and get the final result i was looking for.....

I think changine the gearbox will also be on the cards too, as i'm also a fan of the 2nd gear roundabout

T-Uk did you get a 6-spped yet? I'm interested to hear how that goes.

Dave.

 

Dave

What was the 'result' you got ? do you refer to inlet temp result or torque ? measured in what way ?

Andy

 

I measured 335bhp with a 'road dyno' since i know my measurements are a bit out i'd say that might not even crack 300@star.

I don't remember off hand but the torque figures were about 300nm from 3800rpm peaking about 330nm, which i was pretty chuffed with as the car has some punch at those revs.

FYI that's running 1.3bar boost.

Think i'll be measuring EGT's and AIT's closely when i get back, see if this can't be improved upon a bit.

Dave

 

Make sure the ignition timing and AFR is optimised. Consider breathing restrictions.

I can't see a VF35 breathing better than a 20G at 1.3 bar at 7000 RPM.

[Edited by john banks - 1/13/2004 10:40:12 PM]

 

You don't need as much power as that anyways to powerslide round corners!!

Alan

 

Deltadash Road Dyno results on slight hill

250bhp at 6125rpm, 240Lbft at 4550rpm at the wheels running 97RON + NF

Type UK Sti 8, Standard Induction, H&S downpipe, HKS Silent Hi-power box and centre section,Walbro Fuel pump, HKS s35i plugs, Ecutek re-map

Standard car gave 186.5bhp at 5689rpm, 185.9Lbft at 4974 rpm

 

Actually john I ment with regards to spool up speed and bottom end boost, probably would have made the car a little 'real world' faster if slightly less power.

The mapping was done by steve simpson, all be it on dubious optimax.

I also only took the one dyno run, maybe it wasn't a good one..... Few months till i can try again though so i suppose i should just shut up

Back to searching for a set of headers i think...

 

If you have not already ported your OEM Headers that will show noticable benefits if it is done properly. Also open out the restriction at the beginning and end of the O/E up pipe for a smooth transition.
For a turbo flowing a lot of air the Gruppe S large diameter headers and up pipe are a good choice. Flowing less air than optimal however and you need a smaller diameter up pipe and possibly headers.
Tubular headers.
Putting Gruppe S headers and up pipe on a 250 bhp/260 ft.lb WRX Wagon actually reduced its performance but I hope that situation is redressed with a TD05-06/20G from Andy next week. My intention if performance is not up to expectation is to try a smaller diameter up pipe.
After the turbo you want minimum restrictions so a 3" system as straight as possible and straight through. The H+S open neck 3" down pipe and 3" Revolution exhaust system that was on the STi Wagon is now on the WRX and the STi has a Roger Clark Motorsport open neck 3" down pipe, Scoobymania centre 3" and Scoobymania back box I won from Scooby Shootout. The back pressure in both systems is the same but I suspect the RCMS Scoobymania set up is better simply because it is straighter.
Hope this information helps you.

 

Where and how did you measure back pressure Harvey? How much are you recording?

 

The trouble with porting the headers is the amount of time the car will be off the road

Suppose this is going to be a game of look at the sizes then hope for the best

I don't like doing that.

 

RB5_245

Me no understand - takes 20 minutes to remove stock headers, perhaps an hour to port them (assuming no up-pipe prting), and another 20 to refit.

Richard

 

Ok, First time removing them.... on the street on axle stands. More than 20 mins i think. Fecking about with snapped studs....erm annoying if nothing else.

To be sent away for porting, who knows when they come back. Then replace them, all that time the car is sitting on the street un useable. In theory it shouldn't be a problem but i find these things rarely go to plan!

Steve, what boost are you running out of curiosity? Looking at your graph I seem to get the same figures about 800rpm earlyer, which would make a big difference with the UK gearset. Do you know if STI cams make a big difference here??

 

Use a drill and a die grinder from RS and do it yourself. Borrow a friend's garage for a short while.

 

RB5_245: I have a spare set of O.E. headers and up-pipe here that you can borrow as long as I get a good set back. You can then port the headers and just swap them over if you wish. You could also consider heat wrapping them. The up-pipe also needs doing at the same time for best gains.
Hi Richard: I am surprised how quickly you can port these O/E headers. Takes me a lot longer to get the headers and up-pipe to my satisfaction. I am using cutters that I got from Rs Components. Working on aluminium is easy but cast and stainless headers for me are a long, laborious job. Maybe I have the wrong cutters. Any info on what cutters to use.
John: Can't remember what I said before but H+S D/P and Revolution exhaust and then Roger Clark D/P with Scooby Mania centre and back box, all 3" both gave back pressure of .1 bar flat out in 4th at 8k rpm and in 5th W.O.T. @ 7k rpm.
In each DP I drilled a hole just back from the lamda hole but on the top of the pipe and not the side. Then using the same nipple that you have for the EGT probe I fitted that into the hole which I tapped to suit the thread. I drilled the centre of the nipple out to about 5mm from memory. (On the RCMS down pipe which is the last one I did I actually made a boss to take the nipple because on the H+S dp there was not a lot of thickness to tap into and I ended up welding the nipple to secure it). I then got a bit of copper brake pipe with the appropriate nut to couple onto the nipple thread. My idea of this was to disipate heat and I then used a rubber pipe as a connector and coupled it to a boost guage. Very easy and I can show you the kit next time I see you if you want.
The Scoobymania exhaust is very straight which is what attracted me to it in the first place but its a lot louder than the Revolution both inside and outside which is a disappointment because when I drove Mike Tuckwood`s car with this fitted it was much quieter which is what I wanted. The RCMS dp is extremely well made and that is now the set up on the STi with the Revolution set up on the WRX.

[Edited by harvey - 1/16/2004 11:01:06 PM]