On a standard type r, V4, what is it that limits the boost presure. I know that ultimately the wastegate opens and calls a halt, but what decides when to tell the wastegate to open. I'm sure my car is supposed to run 17psi, but on a warm day it does 13 and on a cold day 14.5. Also, it doesnt peak then drop a little. It just climbs and stays at the maximum.

 

You're ecu initially, unless you have an after market boost controller fitted.

 

as far as i know, its all as it left the factory. Providing it is standard, why would the boost be down. It runs optimax plus millers?

 

I'm not sure what the limit is on you're car, but if i was you i would double check before you go digging for faults mate.

Make sure you have'nt got an after market boost controller fitted, even if it's a crude adjustable bleed valve under the bonnet, or anything at all which could alter the boost pressure.

Failing that, if you really are below you're expected boost, does it boost to exactly the same pressure every time? If not you may have a problem with you're wastegate.

 

yeah its always the same each time give or take 1 psi (temperature dependent) Ill have another look under the bonnet tommorow, everything looks standard subaru, but worth an other look

Thanks.

 

Finally had a look. Definitely seems original and standard under the bonnet