Over boost / Boost cut - 1998 Wrx Sti
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From: Norfolk
Over boost / Boost cut - 1998 Wrx Sti
Hi,
my car is over boosting and hitting boost cut.
the car is a 1998 Version 4 Wrx Sti - import.
mileage is at about 65,000 miles..
the mods are as follows:
3" turbo back exhaust with high flow cat in the downpipe.
K&N cone filter.
Baileys dump valve.
ARP head studs.
A'pexi power FC with commander unit in car.
I've owned the car for about a month now and took it over to Clive Atthowe who is literally 10 minutes down the road.
the Apexi has been fully mapped previously by Andy Forrest by the last owner messed about with the duty cycle for the wastegate.. (as ive been told i wouldn't have known lol, hence me taking it straight to a specialist)
so anyway on the dyno it made 295bhp and 248 lbs Ft which i was chuffed with considering it only has the above mods.
it has 4 boost settings on the power FC.
1 bar - 1.1 bar and then 1.2 bar.
basically under heavy load in 4th gear, building up revs from 2000rpm etc it hits boost cut at 3500rpm - 4000rpm ish..
clive mentioned the A'pexi has a boost cut function when it detects boost going 0.25% over what its set to - he has checked the solenoid and seems clean and ok..
it seems to cut more on 1 bar and 1.1 bar setting, if i accelerate through 2nd 3rd and 4th its fine but its only when building revs from low down in 4th or 5th..
Clive mentioned that waste gate seems to strong.. he would expect it to be softer being an older classic but it seems to be strong. next time it goes back he will have a look at the actuator rod as said this may have been shorten/lengthened.. (i don't know)
does anyone have an experience of this or can offer anything else to be looking at.. i have read alot of posts on here about it but it seems the most common problem is people adding mods and using manual boost controllers without having a tune.. - the car being originally tuned by Andy forrest and then checked and tweaked by Clive Atthowe... thats 2 specialists having looked at it ??
The engine runs great and pulls really well just strange its hitting boost cut.
P.S can post graphs from the dyno if this will help, along with AFR readings etc.. was on the dyno on earlier in April so its very recent data etc.
any help much appreciated.
my car is over boosting and hitting boost cut.
the car is a 1998 Version 4 Wrx Sti - import.
mileage is at about 65,000 miles..
the mods are as follows:
3" turbo back exhaust with high flow cat in the downpipe.
K&N cone filter.
Baileys dump valve.
ARP head studs.
A'pexi power FC with commander unit in car.
I've owned the car for about a month now and took it over to Clive Atthowe who is literally 10 minutes down the road.
the Apexi has been fully mapped previously by Andy Forrest by the last owner messed about with the duty cycle for the wastegate.. (as ive been told i wouldn't have known lol, hence me taking it straight to a specialist)
so anyway on the dyno it made 295bhp and 248 lbs Ft which i was chuffed with considering it only has the above mods.
it has 4 boost settings on the power FC.
1 bar - 1.1 bar and then 1.2 bar.
basically under heavy load in 4th gear, building up revs from 2000rpm etc it hits boost cut at 3500rpm - 4000rpm ish..
clive mentioned the A'pexi has a boost cut function when it detects boost going 0.25% over what its set to - he has checked the solenoid and seems clean and ok..
it seems to cut more on 1 bar and 1.1 bar setting, if i accelerate through 2nd 3rd and 4th its fine but its only when building revs from low down in 4th or 5th..
Clive mentioned that waste gate seems to strong.. he would expect it to be softer being an older classic but it seems to be strong. next time it goes back he will have a look at the actuator rod as said this may have been shorten/lengthened.. (i don't know)
does anyone have an experience of this or can offer anything else to be looking at.. i have read alot of posts on here about it but it seems the most common problem is people adding mods and using manual boost controllers without having a tune.. - the car being originally tuned by Andy forrest and then checked and tweaked by Clive Atthowe... thats 2 specialists having looked at it ??
The engine runs great and pulls really well just strange its hitting boost cut.
P.S can post graphs from the dyno if this will help, along with AFR readings etc.. was on the dyno on earlier in April so its very recent data etc.
any help much appreciated.
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