I have an STI Version 5 with mild mods such as a full 3"exhaust, front Mount Intercooler, water spray kit and adjustable boost controller set at 19psi, and wondering why i can not achieve more than 14psi in first gear and 15-16psi in 2nd gear.....all other gears can find the set 19psi....is this due to factory ecu?.....or is this a norm on all STIs ........id appreciate as much advise as possible as no mechanic has given me a answer cheers

 

Come on guys help this bloke out

 

Which boost controller do you have? It's usual for you not to be able to make peak boost in the low gears with a standard car but I would have thought, you could change this with an aftermarket EBC - but that would also depend on which one you have (presumably).

Matt

P.S. There is another thread knocking about in Drivetrain at the moment which discusses this....

 

To get full boost in lower gears you need to use a much higher solenoid duty cycle to achieve this. In first gear and second gear the turbo does not have as long under decent engine load to reach full boost using base duty cycles intended (and necessary for higher gears where the load is higher and more prolonged = more and more prolonged gas flow through the turbine).

 

i have a turbosmart manaul twin stage adjustable boost controller fitted to it...
Can someone tell me why the boost will only do 14-15psi in 2nd gear when accelerating hard from stand still, but if i accelarate while cruising in 2nd gear it will peak to the desired set boost 19psi? and also is 19psi to high with my mods? thanks

 

Yes, this is exactly what I get too. MY01 JDM STI RA.

Accelerating hard thru the gears from standstill, I get 1bar held with no spike in gears 2, 3 and 4. However, accelerating from a constant throttle from gears 3 or 4, I can see as high as 1.4bar with WOT.

Why?

 

RT .....thanks for responding,.........if u ever find out why our rexs boost the way they do, please tell me, id love to know ?

 

I'm actually quite fed up trying to figure out what the std JDM ECU tries to do. Waiting for MOTEC or AUTRONIC to come up with something...

Closed loop management is good for main stream sedans. For performance applications, we really need open loop ECU's.

 

so im guessing we dont have any problem with the car.....f@#$ it im gonna upgarde the ecu too