Power increase advice
#1
Power increase advice
im looking at taking my 2003 blob sti uk off the road for a while and doing an engine rebuild as the car is now on 75k and the clutch is on the way out
im looking at taking the car to around 450bhp
the mods i have so far are
what mods should i do with the rebuild?
how much power can the standard internals and gearbox take?
thx guys
J
im looking at taking the car to around 450bhp
the mods i have so far are
- APS Induction kit
- Uprated fuel pump
- Full decat TSL exhaust and down pipe
- WRC Remap
- AST Suspension with anti dive kit, poly bushes and 4 wheel alignment setup
what mods should i do with the rebuild?
how much power can the standard internals and gearbox take?
thx guys
J
Last edited by jammer1984; 07 December 2009 at 10:17 AM.
#2
V.8 Sti's like yours will take 400-430bhp all day long without any issue. After that you start to increase your chances of engine failure thus living on borrowed time, although i've heard of STi's taking over 500bhp on std internals and still running strong after 2-3+years. You take your chances really but at 450bhp it's not beyond the realm of possibility that your engine would be fine with that even at 75K miles.
75K miles isn't a huge amount of mileage in STi terms. If it were a WRX engine then i'd be concerned although you can take them up to c.320-330bhp but at 75K miles even withing max safe bhp limit long term prognosis isn't great for the WRX.
IMHO get more power from your std STi if you can, wait until it goes bang and then do the rebuild. You're going to do a rebuild anyway so you have nothing to lose. Your engine may well surprise you!!
Out of interest, 358bhp is well within your V.8 safety limits and at the limit of the OEM VF35 turbo used on the V.8. The VF35 is not a laggy turbo so i presume you're using a different turbo like a TD05 18/20G.
18G's are still very good for not being too laggy but the 20G (as i run) is very laggy, especially on a 2L. Once it's going though it keeps on going right to the red line but it does sound like your car needs a remap paying special attention to AFR's and the AVCS map. Tuning AVCS properly can reduce some of that lag. Mine is laggy in 1st/2nd/3rd gears and doesn't really get going till about 3800-4000rpm, although in 4th and 5th it comes in around 3500rpm which is about right for the 20G.
75K miles isn't a huge amount of mileage in STi terms. If it were a WRX engine then i'd be concerned although you can take them up to c.320-330bhp but at 75K miles even withing max safe bhp limit long term prognosis isn't great for the WRX.
IMHO get more power from your std STi if you can, wait until it goes bang and then do the rebuild. You're going to do a rebuild anyway so you have nothing to lose. Your engine may well surprise you!!
Out of interest, 358bhp is well within your V.8 safety limits and at the limit of the OEM VF35 turbo used on the V.8. The VF35 is not a laggy turbo so i presume you're using a different turbo like a TD05 18/20G.
18G's are still very good for not being too laggy but the 20G (as i run) is very laggy, especially on a 2L. Once it's going though it keeps on going right to the red line but it does sound like your car needs a remap paying special attention to AFR's and the AVCS map. Tuning AVCS properly can reduce some of that lag. Mine is laggy in 1st/2nd/3rd gears and doesn't really get going till about 3800-4000rpm, although in 4th and 5th it comes in around 3500rpm which is about right for the 20G.
#4
Edited to add: The gearbox is more than strong enough for your requirments, just get a proper turbo like the MD321T and bigger injectors c.700cc, + FMIC and you're away!! If you still have standard headers and uppipe it's worht changing to something like the GTspec GenII or Kakumei system.
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#11
#12
i didnt have it mapped it was done before i bought it
as i said up a drag strip it is great it pulls all the way up to the redline very well, a lot of people commented on how fast it is for the power its producing
but in track conditions you have to get exactly the right gear or your screwed
as i said up a drag strip it is great it pulls all the way up to the redline very well, a lot of people commented on how fast it is for the power its producing
but in track conditions you have to get exactly the right gear or your screwed
#14
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i didnt have it mapped it was done before i bought it
as i said up a drag strip it is great it pulls all the way up to the redline very well, a lot of people commented on how fast it is for the power its producing
but in track conditions you have to get exactly the right gear or your screwed
as i said up a drag strip it is great it pulls all the way up to the redline very well, a lot of people commented on how fast it is for the power its producing
but in track conditions you have to get exactly the right gear or your screwed
#17
At most you might want to port your headers, de-lug them, then wrap them and the std uppipe and see how that goes before spending any more dosh. These are things you can do yourself. The standard uppipe is pretty good with the only difference being that unlike aftermarket uppipes it's not made of stainless steel but it does a good job.
The std map calls for just over 1bar of boost from about 2800rpm at 43% throttle. I wouldn't have said that was particularly late as it's a factory compromise between cruising economy and blatting power but in practice it does start to come in fairly early. Without looking at your car it's difficult to say what it is because it probably will be something to do with mapping but also you could have an uppipe leak or cold air leak somewhere contributing to a lack of boost low down.
The std map calls for just over 1bar of boost from about 2800rpm at 43% throttle. I wouldn't have said that was particularly late as it's a factory compromise between cruising economy and blatting power but in practice it does start to come in fairly early. Without looking at your car it's difficult to say what it is because it probably will be something to do with mapping but also you could have an uppipe leak or cold air leak somewhere contributing to a lack of boost low down.
#20
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Ran one Oe engine to 200k at 330bhp for most of it's life.. and it was still running when removed
Simon
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