Hey,

I am having a boost issue and think I know what it is , but would like some help. I noticed that my pattern was good, but running stock boost, so I was thinking my boost controller wasn't working. After testing it and still no change I did the unthinkable. I left the wastgate's wide open knowing that they would spool to never ,never land. Instead, first gear did 7, second gear did 8,6,7 and then slowly went down to 5 right before I shift into 3rd. In 3rd it holds 10 psi almost all the way throught the gear till it finially fads down to like 8. take note. THIS IS WITH THE WASTEGATES UNHOOKED. They should spool till they blow up.

I now believe I have nailed the broblem down to either being that the wastegate springs aren't holding the wastegate clossed or the turbo's are going out. So I turn into the crazy caveman that I am again, and I visegrib the wastegates so they can't move, and I get the same exact boost pattern as I did before.

CONCLUSION: What I am thinking then, is that my turbo's are on there way out, BUT I JUST DON'T WANNA belive it as that would SUCK! Does anyone else have any idea's of other things it could be?

J. R.

 

boost leak is my guess, check all of your intake tubes for leaks

http://www.autosportracetech.com/RX-...leshooting.htm

 

After reading that do you think that i have no transition maybe? Maybe my turbo's arn't blown, but the middle actuator is never crossing over exhaust gas's to the second turbo, so it never comes online, and so with only the Primary turbo going I can only get the boost patterns I am getting.

Anyone think that theory could be true?

J. R.

 

Not the turbos, that's almost for sure. I would not continue running with the wg open, or you many run down that road sooner than you'd like.

First, I'd check all of the intercooler / y-pipe couplings thoroughly for slits or holes. Then, I'd tee the boost gauge inline with the vacuum and pressure chambers to ensure it generates and maintains vac and pressure. Last, I'd tee into the line feeding each of the actuators to observe the input coming from the solenoids. (Remember, the turbo control actuator has two: one pressure, one vacuum).

Do you have a mityvac?

Dave

 

Are you getting this boost dip (you say it's "7-5-7") at 4500 rpm? If so, your actuator control is working, albeit possibly not properly.

Your explanation is pretty vague. You refer to the "wastegates" in your original post; did you disconnect the pre-control also? What kind of boost controller are you using (how is it hooked up)?

 

I was usuing a profecB. Its not that. To test it I used my MBC that I know works and still got the same pattern. When I froze up the wastegates it was the primary and secondary. I didn't play with the other two that control which turbo recieves intake air, and exhaust. Forget what you call those other two. I am a single turbo guy trying to get to know the twin set-up.

Qustions........then. SOmeone help with these to help me solve it.

1. Could it just be that only one turbo is spooling to give me that funky pattern? Expaining why I can get higher boost in higher gears?
2. Could it be a leak that would give me the pattern of higher boost in higher gears? Doesn't seem likly, a leak would give me the same boost no matter what.
3. Anyone ever seen that kinda pattern before, where you could get more boost the higher the gear you were in? If so what did it end up being on your car?

J. R.