quick question my cars is chipped with apr 93 software, and i would like to know if anybody has problems loosing boost on high rpms.
my car can hold the boost for a while like 10-15psi but once i go faster it starts to slowly drop psi , the thing is i'll be revving at 5000rpm and my boost will stay at 10psi. In low rpms i can boost up to 18 psi, sometimes it'll spike to 21 psi once i go faster . does this mean more RPM less Boost?, In 4th gear ill push the pedal all the way and boost 18psi, thenthe higher rpms the boost starts to slowly decrease until 10psi at 6000rpm.
anybody know why? Thanks

 

Its based on the turbocharger you have. The turbo simply cannot sustain the boost at high RPM. I assume you are using OEM turbo.
If you have a better turbo, bigger one, then you might have a problem.

 

its just the stock turbo

 

so the stock turbo cant hold the pressure, ill need to upgrade the turbo?

 

its called the tiny turbo effect, as the rpms increase the back pressure becomes to great for the turbo to dispurse and therefore you lose boost. Kinda sucks but thats what happens, on the pluss though tiny turbo effect means you spool sooner. a test pipe/ exhaust will help you hold boost longer but not as much as you would probably like. the best thing is to get a turbo with a bigger turbine, however it will take it longer to spool.

 

THANKS for your help.

 

does your boost spike back up after you pass 6k? did you change your dv?

 

The boost will never come back after 6k.... PERIOD. the turbo can not keep up with the flow. The best way to hold it longer is with a boost controller. A mbc will do very well and a more expensive ebc will do even better

 

+1 for ebc, but you gotta spend the time to tune it

 

but well worth it when you go BT also