ok, before I went turbo, I always thought that a t25 would be fully boosted at like 2800-3000 rpms, at least thats what everyone else says, but I have a t25 with 2.5" intercooling piping, and I START boosting at 2800-3000rpms, but I don't reach my 9 psi mark until like 5800-6000rpms, is that the same for everyone else?

 

That doesn't sound right. I build boost at about 2900 and am full spool at 3400ish. I am running 8.5 psi on a Saab T348/42 which is similar in size to yours.

 

im sorry pa2play but I dont remember what kind of an exhaust you have?

If you still have a stock exhaust, try running it without your cat and your exhaust. My setup was doing exactly what yours was doing before I dropped the exhaust and found out it was too small for turbo. Mine would start boosting about 3-4k but never reached full boost until 7-8k. But it reaches full boost by 4k. I know we have different engines but try dropping the exhaust and running it open downpipe and see if there is a difference...

 

could you have an exhaust leak before the turbo?

 

I'm running the greddy sp exhaust 2 1/4" with a high flow cat, which I'm taking out right now , as far as the exhaust leak b/f the turbo, on my hm manifold, there is the SMALLEST (I mean minsquel) hole on the back, like a pin hole, and the only reason I havn't fixed it is because I would have to take EVERYthing off to get to it.

 

You could also try an MBC. That may help.

 

WOW!Im running the same turbo and I dont see full boost till about4500 rpm or so.

And for the record a saab t3 is a little bigger than a t25.

 

Uhm... if you have an exhaust leak... that could be it if your boost lag still persist after taking off the exhaust.

 

check your wastegate too. If the flap isnt totally sealing, it will cause the turbo to spool later than it should.

 

I'm in full boost basically whenever I am at WOT. on say a third gear run, I'll punch it at 2k and be fully boosted at 2.3k, and the boost will last till redline.