Boost level changes from day to day. Why?

[JNZTRBO]

I have a 99 GSX with a SBR EVO 3, Greddy full IC kit, 550's, 255, AFC 2, 3" turboback. Some days I get 20psi, then the next down to 15 and sometimes even lower. Can anyone explain why? Thanks.

 

[oldman]

I have a 99 GSX with a SBR EVO 3, Greddy full IC kit, 550's, 255, AFC 2, 3" turboback. Some days I get 20psi, then the next down to 15 and sometimes even lower. Can anyone explain why? Thanks.

1. Would that be a solid 20psi or creeping 20psi.

2. Which boost controller do you have?

3. Have you done any leak test yet after any of these mods involving the intake tract?

4. Where is the logger? What are you tuning with?

 

[RacethisTSI]

it could simply be from the temp of the air...i have a bad external waiste gate right now(saving to buy a new one) and i usually cant go 60% therotle with out going over 20 psi. i floor it a get fuel cut at about 25 to 27psi( not good to go that high on pump gas)...any ways. its been cooler around here and i went out and ripped on my car 100% and i stayed right about 20 psi. didnt hit fuel cut at all....cold air is more compressed and condense and there for easyer to build more power from less boost. hot air is more expanded so hot air would build more boost but give you less power.