Ok i have an 89 tII and i cant figure if i have boost creep or a leak. i get on it and my boost jumps to 10 psi, then while i going threw the rpm's it slowly drops to about 5 by the time im at redline. now i cant hear any noise like a leak. but i also didnt think that boost could creep to 10 and then go down to 5. ive checked all my IC piping and all the clamps are tight and my BOV is on tight and not leaking. anyone have any ideas?

 

Your turbo may be in need of a rebuild, check for shaft play. You also could just be plain out flowing the turbo, boost drop off is not uncommon on cars with open intake and exhaust. If the turbo is worn at all this will only exacerbate the problem.

Daniel

 

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/cant-hold-boost-redline-301780/

 

My turbo has some shaft play, nothing too bad or that i havent felt on friends cars befor. But do you think that if i turn up my boost ( i have the trubo xs manual) that it might help, or just hurt the problem?

 

i have my turboXs manual boost controller set at 10 psi and boost falls off just as you described......from what i have read it is from the stock turbo not being able to flow enough......time for a hybrid i guess


since i (we) are at 5psi at redline instead of 10psi.....arent we losing somewhere around like 50hp on top end???

On my dyno sheet, it falls right on its *** at 5500rpm.......

 

my T2 turbo has 170k on it, original and has a few mm of side play. with TID mod and 3" open exhaust and ported wastegate and it can't even hold itself to 5psi if it wanted to, i would say your problems lie either in the boost controller or if you have an aftermarket blow off valve i would suggest checking that as well.

 

10psi with a full exhaust is not creep, it's perfectly normal turbo behaviour.