Max safe boost on P1?
17 March 2002, 05:45 PM
#1
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A question for the experts here.
If fuelling is adjusted appropriately, what is the maximum boost level that the P1 (or STI 5) can be taken up to safely without compromising the longevity and reliability of the engine. I am basically looking to get the most from my engine in terms of torque and bhp increases, without uprating any internals or adding a FMIC etc. The car is a P1 and has a catless straight through 2,5" exhaust system and no other mods. The present boost is about 1.1 bar.
I am sure that if UK cars can safely have their boost levels raised to 1.2-1.4 bar on standard internals, surely the STI engine would be able to whithstand a little more without any dire consequences?
Any help/advice, much appreciated.
Many thanx,
MS
If fuelling is adjusted appropriately, what is the maximum boost level that the P1 (or STI 5) can be taken up to safely without compromising the longevity and reliability of the engine. I am basically looking to get the most from my engine in terms of torque and bhp increases, without uprating any internals or adding a FMIC etc. The car is a P1 and has a catless straight through 2,5" exhaust system and no other mods. The present boost is about 1.1 bar.
I am sure that if UK cars can safely have their boost levels raised to 1.2-1.4 bar on standard internals, surely the STI engine would be able to whithstand a little more without any dire consequences?
Any help/advice, much appreciated.
Many thanx,
MS
17 March 2002, 09:50 PM
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Mines an sti5 (pretty much same engine as the P1)and has not had any internal work done (yet)
This is running at 1.4 bar (fluctuates between 1.37-1.42 bar on the link) and has done this trouble free for about 30000 miles. As I have uprated the power I have had problems with trying to hold the boost.
I had to put on a 3 port boost solenoid and an uprated actuator to achieve some stability with the boost
The turbo is a MD195 Turbo Dynamics hybrid, but was comfortably able to run 1.4 bar on the VF28 as well.
The Front mount just allowed me to run a bit more ignition advance as does the water injection. This will add about 20-30bhp on the rollers
Depends whose rollers your on - but if your just wanting to increase boost to 1.3/1.4 bar I guess you'll be looking at about 325-330bhp at Well Lane
I did notice a difference upping the boost on the VF28, but I noticed this even more with an uprated turbo, probably cos it was more laggy - but when it kicks its great...
The clutch should have non probs on 325bhp, mine only recently went after 2.5 years
But 1.4 bar is the max safe boost your looking at with minimal overboost. 1.3 bar on a UK.
This is running at 1.4 bar (fluctuates between 1.37-1.42 bar on the link) and has done this trouble free for about 30000 miles. As I have uprated the power I have had problems with trying to hold the boost.
I had to put on a 3 port boost solenoid and an uprated actuator to achieve some stability with the boost
The turbo is a MD195 Turbo Dynamics hybrid, but was comfortably able to run 1.4 bar on the VF28 as well.
The Front mount just allowed me to run a bit more ignition advance as does the water injection. This will add about 20-30bhp on the rollers
Depends whose rollers your on - but if your just wanting to increase boost to 1.3/1.4 bar I guess you'll be looking at about 325-330bhp at Well Lane
I did notice a difference upping the boost on the VF28, but I noticed this even more with an uprated turbo, probably cos it was more laggy - but when it kicks its great...
The clutch should have non probs on 325bhp, mine only recently went after 2.5 years
But 1.4 bar is the max safe boost your looking at with minimal overboost. 1.3 bar on a UK.
17 March 2002, 09:55 PM
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I'm not aware of anyone without internal work running more than 1.4 bar on an P1/import. If someone is I dont think it would last very long.........
You should'nt just look at boost though - you can get more bhp/torque by playing with ignition advance on a fully mappable ECU..
But its very much a case of diminishing returns.. On the next Well Lane day we'll see what the limits are with the internal engine. I have the Front Mount/ported headers - am having WI - bigger turbo, etc, etc - I supect this will be about 370bhp at Well Lane = about 345bhp at PowerEngineering = 310bhp at Powerstation (of course there are the occassional fluke cars that achieve more than this on lower boost and ignition advance, which are rare)
You should'nt just look at boost though - you can get more bhp/torque by playing with ignition advance on a fully mappable ECU..
But its very much a case of diminishing returns.. On the next Well Lane day we'll see what the limits are with the internal engine. I have the Front Mount/ported headers - am having WI - bigger turbo, etc, etc - I supect this will be about 370bhp at Well Lane = about 345bhp at PowerEngineering = 310bhp at Powerstation (of course there are the occassional fluke cars that achieve more than this on lower boost and ignition advance, which are rare)
18 March 2002, 12:25 AM
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Thanx for the replies so far guys.
So it seems that 1.4 bar and no more is the way to go then. What sort of torque increases should I be able to achieve then? Over 300 lb/ft would be nice
In terms of engine longevity, will I see things wearing out a lot quicker, such as turbo, gearbox, clutch etc? I realise that increasing power will always be a compromise, but just wondering how much quicker things are going to wear out.
Thanx again guys.
MS
So it seems that 1.4 bar and no more is the way to go then. What sort of torque increases should I be able to achieve then? Over 300 lb/ft would be nice
In terms of engine longevity, will I see things wearing out a lot quicker, such as turbo, gearbox, clutch etc? I realise that increasing power will always be a compromise, but just wondering how much quicker things are going to wear out.
Thanx again guys.
MS
18 March 2002, 08:59 AM
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Why the comment on 1.4 bar on import and 1.3 on UK?
The Sti has a higher redline, achieved through forged (lighter) pistons (and maybe cams), giving more power than the UK car through Revs. Compression ratio, con rods, crank etc are the same.
Now at the bottom / midrange why should a uk not be able to run the same boost as an STi? The only difference here is again the forged pistons, which when compared to the cast jobbies in the UK, should take similar boost at the lower / mid range RPM. Forged having a slightly higher temp limits on the crown.
At high rpm, I would tend to agree. You need to lower boost on the UK car to protect from high temp piston damage. Obviously you have a lower RPM limit as well...........
Interested as just fitted a VF30 to a UK car and going for a re-map soon!!!!
The Sti has a higher redline, achieved through forged (lighter) pistons (and maybe cams), giving more power than the UK car through Revs. Compression ratio, con rods, crank etc are the same.
Now at the bottom / midrange why should a uk not be able to run the same boost as an STi? The only difference here is again the forged pistons, which when compared to the cast jobbies in the UK, should take similar boost at the lower / mid range RPM. Forged having a slightly higher temp limits on the crown.
At high rpm, I would tend to agree. You need to lower boost on the UK car to protect from high temp piston damage. Obviously you have a lower RPM limit as well...........
Interested as just fitted a VF30 to a UK car and going for a re-map soon!!!!
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