on a completely stock mk3 (provided it is in good mechanical order and had it's hg done) can run generally 10-11psi no probs
on a bpu... intake, exhaust etc you should still be able to run bout 10-11
if you have a free flow 3" exhaust from turbo (no not turbo elbow but turbo itself) back, then you will have to lower your boost slightly to bout 10.. usually this is to counter hitting fuel cut
if you have aftermarket intercooler hardpipes, bigger intercooler, free flow exhaust and intake done you will probly experience fuel cut earlier so your boost will most likely have to come down more
now don't get this the wrong way... by lowering your boost you aren't losing power, by doing these mods you have increased your air flow so much that you now hit fuel cut earlier than your previous restrictive system
also if you have all these things and an upgraded ct26 you might just have it worse and it may be becoming intolerable lol
so heres where the:
lexus afm/550cc injector mod
safc & lexus + 550cc
or if you got money to burn.. don't waste any time and get an aftermarket ecu installed and tuned at your local dyno shop
or you can buy an hks type k fuel cut defender
with the fuel cut defender please do not install it and think you can run 15psi of boost... you will kill your engine
if you wish to go this way please get a professional to install it and get your air fuel ratios checked on a dyno... i would say ideal with a fcd with the max bpu mods (exhaust, intake, ic, ic hardpipes, ct26 upgrade etc) would be about 12psi safely MAYBE.. on 440cc injectors... that is why you need a dyno, on 550cc injectors it would naturally be higher
engine repairs can be very expensive, you may need new pistons, rods, rings, bearings, head gasket (for sure), a great many things can go wrong and can be very expensive... these can cost up to $3000 or $3500usd depending on how much damage you do... so please keep in mind these repairs and if you don't have a spare $3000 lying around, don't wind your boost up unless you know you have the fuel to supply it
this is only a guide in modifications... you need a dyno to verify as every engine is also different... so please remember this and happy boosting
