Spannersrx7

Hey guys I have just installed a greddy prospec II recently and the boost falls off at high rpm..what would cause this?

mazdaverx713b

iTrader: (91)

in a lot of cases its normal for the boost to drop at higher rpm by a couple pounds, especially with a few mods and a stock turbocharger. basically saying the turbo isnt as efficient as it could be to hold boost through the rev range.

Spannersrx7

The turbo has been upgraded to a t04 with series 5 exhaust housing

NZ_87_TURBO

bro my stock S5 turbo fall of hard out. will crank 11psi till about 5500 then fall off to about 7psi by red line. Ive got a 3" turbo back exhaust and 3" inlet. what gives aye. wheres my solid 11pounds from 3000 to redline

must be a shitty turbo

rotaryracer11

wow mine like holds 14.1 psi until 5500 and than drops to 5 psi by red line.....but mind u i have a turbo manifold leak

Spannersrx7

oh real I thought iu as the only one..I get 10 pounds then it falls away

NZ_87_TURBO

Apparently the S5 and probably the S4 turbos cant flow enough and just fall away at hi rpm

tandolla

iTrader: (1)

yes mine does the same thing as wel... ill be at like 10 then it will drop to like 5 but i also think i have a manifold leak as wel..

mort2002

iTrader: (1)

yep ill be at like 12 and drop to about 7psi....