Which mod would be more beneficial?
14 January 2011, 11:09 AM
#1
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Which mod would be more beneficial?
Hi All.
A mate of mine has a V3 STI its fairly standard at the mo, just a panel filter, sport cat and 2.5" exhaust, with an Apexi ECU and is running 291bhp. He is about to add an uprated fuel pump and have the map tweaked so he can run more boost.
But before that he wants to add another mod first, either a FMIC or tubular headers and up-pipe. What we would both like to know please is which would offer the best gains?
Thanks
Andy
A mate of mine has a V3 STI its fairly standard at the mo, just a panel filter, sport cat and 2.5" exhaust, with an Apexi ECU and is running 291bhp. He is about to add an uprated fuel pump and have the map tweaked so he can run more boost.
But before that he wants to add another mod first, either a FMIC or tubular headers and up-pipe. What we would both like to know please is which would offer the best gains?
Thanks
Andy
14 January 2011, 11:12 AM
#2
No need for Tubular Headers at that level of tune IMO. A Harvey smith up pipe woulf help spool.
Also no real need for the FMIC but if the map is being tweeked anyway it can certainly help to keep charge temps in check. Again Harvey sells a well priced Hybrid FMIC
Also no real need for the FMIC but if the map is being tweeked anyway it can certainly help to keep charge temps in check. Again Harvey sells a well priced Hybrid FMIC
16 January 2011, 12:22 PM
#5
With the right mods done in the right sequence you should get to around 335 bhp which is what I got out of my STi 3 Wagon during the development stages. It did not have the advantage of the Apexi ECU. The power output at that time was 335 bhp 331 ft.lbs.
You need a fuel pump immediately. If it is still on the OE, the existing is about 14 years old.
Tubular headers would be a good step backwards and reduce spool and induce lots of lag.
By the time you get to 335 bhp you will need a front mount intercooler but right now you may not for a modest increase. By the way, I was seeing ACTs off the clock at 70C when the car was at 335 bhp doing 0-100 mph in relatively cool conditions.
The FMIC could be either a Hybrid GT £325 or Hybrid GT2 £375. Please do not compare the price of these intercoolers with inferior crap you see advertised for £200 or whatever.
The spec I had to achieve 335 bhp on OE injectors, top mount, ECU and induction:
3) The headers were also OE but ported with matched uppipe.
1) Walbro fuel pump (£75 plus £25 fitted).
2) 3" open neck downpipe, (my own downpipe £215) full decat exhaust system (I was using Revolution but not their downpipe). 3" exhaust.
You need to get rid of the sports cat but a 2.5" exhaust will do the job to 400 bhp probably and you could get a 3" to 2.5" downpipe. That will immediately give you power without the cat.
3) As stated above, I ran a set of my own ported headers all DEI heat wrapped with matched uppipe £369. Fitting £75.
4) Standard induction box with K+N filter but various tests showed there was nothing wrong with the OE filter other than it clogged up after 3000 miles and the advantage of the K+N was that it could be cleaned every 2500 miles with the K+N supplied cleaning kit.
5) Not recommended but because I was on the OE ECU I used a GBE boost valve, about £40 to increase boost. I was able to do this because I have LM-1 and LM-2 AFR monitoring equipment along with det cans and Phormula Knock Analyser Pro.
If the simplistic approach of a £40 boost valve is copied elsewhere without the ability to determine engine fuel requirements it could well end in tears.
Both the turbo and injectors were maxed out.
The only thing I think the car had other than the above was a Zero Sport inlet tract piece to get rid of the ribbed section between the MAF and actual inlet tract under the inlet manifold.
I then fitted an Apexi ECU and 550 injectors and one of my own development turbos.
I was not over impressed with the Apexi ECU which was on the car for three weeks and then went to a Simtek. I want to stress that the Apexi serves a purpose but does have limitations and one of these is a rather basic boost control. However, it is streets ahead of a £40 boost valve.
As everyone was raving about how good STi top mounts were I fitted an STi 8 top mount against my better judgement. This would give me first hand knowledge. In stages with turbo development the car got to 392 bhp and was now on a cone filter system with spun aluminium trumpet and silicon joiner.
We ran the car on Steve Simpson's rollers at TEG Sport and got 392 bhp from final mapping. This car had now done an inordinate number of rolling road runs and I took the car away and fitted a Hybrid GT, not GT2. On return, straight out the box the car did 401 bhp and with mapping 410 bhp. Air charge temperatures with the Hybrid GT FMIC were in the low 20s whereas the STi 8 TMIC had been in the 40s on a cooler day than the GT runs.
I hope this factual information assists you and others.
As an aside I won't be wasting time with STi 8 top mounts again. We subsequently fitted one for a customer and it takes more time to do this properly with the manufacture of brackets to fit to an STi 3 or 4 than it does to fit a front mount.
Oh and to get the STi 8 TMIC to work properly or as good as it can you need the STi 8 scoop and undertray.
Enjoy your modding. The STi 3 and 4 are very good bases for modification work and good places to learn but it becomes addictive. The car above is still with me, now around 422 bhp on the same turbo and engine internals. I have just replaced the cylinder head gaskets and plan to take it to between 440 and 450 bhp in the near future, still on standard internals.
You need a fuel pump immediately. If it is still on the OE, the existing is about 14 years old.
Tubular headers would be a good step backwards and reduce spool and induce lots of lag.
By the time you get to 335 bhp you will need a front mount intercooler but right now you may not for a modest increase. By the way, I was seeing ACTs off the clock at 70C when the car was at 335 bhp doing 0-100 mph in relatively cool conditions.
The FMIC could be either a Hybrid GT £325 or Hybrid GT2 £375. Please do not compare the price of these intercoolers with inferior crap you see advertised for £200 or whatever.
The spec I had to achieve 335 bhp on OE injectors, top mount, ECU and induction:
3) The headers were also OE but ported with matched uppipe.
1) Walbro fuel pump (£75 plus £25 fitted).
2) 3" open neck downpipe, (my own downpipe £215) full decat exhaust system (I was using Revolution but not their downpipe). 3" exhaust.
You need to get rid of the sports cat but a 2.5" exhaust will do the job to 400 bhp probably and you could get a 3" to 2.5" downpipe. That will immediately give you power without the cat.
3) As stated above, I ran a set of my own ported headers all DEI heat wrapped with matched uppipe £369. Fitting £75.
4) Standard induction box with K+N filter but various tests showed there was nothing wrong with the OE filter other than it clogged up after 3000 miles and the advantage of the K+N was that it could be cleaned every 2500 miles with the K+N supplied cleaning kit.
5) Not recommended but because I was on the OE ECU I used a GBE boost valve, about £40 to increase boost. I was able to do this because I have LM-1 and LM-2 AFR monitoring equipment along with det cans and Phormula Knock Analyser Pro.
If the simplistic approach of a £40 boost valve is copied elsewhere without the ability to determine engine fuel requirements it could well end in tears.
Both the turbo and injectors were maxed out.
The only thing I think the car had other than the above was a Zero Sport inlet tract piece to get rid of the ribbed section between the MAF and actual inlet tract under the inlet manifold.
I then fitted an Apexi ECU and 550 injectors and one of my own development turbos.
I was not over impressed with the Apexi ECU which was on the car for three weeks and then went to a Simtek. I want to stress that the Apexi serves a purpose but does have limitations and one of these is a rather basic boost control. However, it is streets ahead of a £40 boost valve.
As everyone was raving about how good STi top mounts were I fitted an STi 8 top mount against my better judgement. This would give me first hand knowledge. In stages with turbo development the car got to 392 bhp and was now on a cone filter system with spun aluminium trumpet and silicon joiner.
We ran the car on Steve Simpson's rollers at TEG Sport and got 392 bhp from final mapping. This car had now done an inordinate number of rolling road runs and I took the car away and fitted a Hybrid GT, not GT2. On return, straight out the box the car did 401 bhp and with mapping 410 bhp. Air charge temperatures with the Hybrid GT FMIC were in the low 20s whereas the STi 8 TMIC had been in the 40s on a cooler day than the GT runs.
I hope this factual information assists you and others.
As an aside I won't be wasting time with STi 8 top mounts again. We subsequently fitted one for a customer and it takes more time to do this properly with the manufacture of brackets to fit to an STi 3 or 4 than it does to fit a front mount.
Oh and to get the STi 8 TMIC to work properly or as good as it can you need the STi 8 scoop and undertray.
Enjoy your modding. The STi 3 and 4 are very good bases for modification work and good places to learn but it becomes addictive. The car above is still with me, now around 422 bhp on the same turbo and engine internals. I have just replaced the cylinder head gaskets and plan to take it to between 440 and 450 bhp in the near future, still on standard internals.
Last edited by harvey; 16 January 2011 at 12:24 PM.
16 January 2011, 01:59 PM
#7
Mapped properly with an efficient FMIC you will still get good throttle response but a good bit more power than you would get with an STI 8 TMIC.
Do your own research and you will find that many people that have discarded STi 8 top mounts lay bare the myth that a front mount causes lag.
Do your own research and you will find that many people that have discarded STi 8 top mounts lay bare the myth that a front mount causes lag.
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16 January 2011, 11:18 PM
#12
Start a thread telling us what you want to achieve. 380 bhp may be a realistic target and I will give you as much input as possible, as will others. Send me a link to ensure I see it.
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