I have a MY00 2.5RS.. with an sti block, and stage three turbo kit from forced air tech.. I have noticed lately that under boost my car doesn't feel quite as quick, and that my boost needle will shake around quite a bit.. this only happens under boost, and never under vaccuum. the car has no cel, and runs fine .. it just sometimes stunbles under boost, and the needle will shake.. today i was driving on the highway and I was listening to my turbo , and it sounded like it was jumping around.. not a constant whistle common with turbos, kind of broken up sound.. It is hard to explain.. the only thing I can think that would be wrong. is something with the wastegate.... hell I don't know.. does anyong know what the deal is?

 

what kind of boost controller are you running?

 

bump
I did have some crappy homemade ( Home Depot style) boost controller that I had set at 10.5 psi, and it worked great.. ( or so I thought) no boost spikes anything like that.. then I noticed my boost started to flutter and there was a power loss.. so I took off the boost controller and used the spring in my wastegate that is a 7lb spring, and it is doing the same thing.. making me think it is the wastegate.. has this happened to anyone before?

 

do you have a split in a vacuum line that is going to your wastegate or your Fuel Pressure regulator?

My car did this and that's all it was.

 

don't know I will check... which fuel pressure regulator? the RRFPR or stock?

 

stock.

you still running stock fuel injectors?

If so, I have some advice:
550cc injectors and a FTC1 (with data logging)
Makes a big difference.
injectors about 400
FTC1 550

Another rather large investment, but you don't have to wait for the RRFPR to keep up and you don't need a voltage clamp anymore.

 

I have the FTC1 coming w/ 440cc cc

 

oh yeah, that's right you asked me about it in the hawaii forum.
440s huh?
That makes tuning a little tougher. I can't send you a proven map for 440's. But I can give you my 550cc map and you can change it by a certain percentage.

 

this has happened to me also! you have to change the location of your vacuum/boost source. I'm not sure which one I had mine connected to but the boost would flucuate(spelling?)under full boost. I just changed ports and everything was fine!

 

ok jow far away do you have your RRFPR and stock FPR fromm the vaccuum source? My RRFPR is on the drivers side of my engine bay with about 2.5 feet of vacuum hose.. could this be the gremlin in my motor?

 

mine was in the same location when I used it.

Don't worry about the RRFPR, because once you get your injectors and FTC1 you won't need it anymore.

BTW, did you get the maps I sent you?

 

this wouldn't cause a fluctuation of pressure if it was the problem.

Where does your boost gauge tap in at??