I'm stumped...
 

Ok, I had a blown primary turbo and got a used set and finished putting them in but now I have a problem. When boosting I get to 4~5 lbs and the car just acts like it hits a wall, boost goes back down to nothing. It doesn't matter what gear or rpms its only at 4~5lbs of boost. I can half throttle it at under that and itll go throught the revs just fine. Can someone help me out with some ideas i'm stumped and this is really annoying.
Thanks in advance.

Oh car is 93 R1, still sequential, dp, catback and intake and boost controller only mods.

Are you collapsing an intake hose, or something similar?

Are you running sequential or non-sequential???

Still sequential. it's not on the crossover it doens't matter what rpm it can be 3k or 5k doesn't matter 4~5lbs = a wall for me. It revs fine in neutral it's just with that magic number of boost it has issues.

I'll go check the intake hose's and see if they seem like there collapsing. But didn't have this problem before.

It sounds like either the wastegate or the wastegate controller is bad on the used turbos.

I swapped my wastegate over my old set, and it worked fine before. These turbo's came off a car quite awhile ago but in working condition and ended up going single. Maybe I should try to swap the wastegate with the one's that came with the used twins...

Ok, swapped the wastegate and still same exact effects, 4~5 lbs and wall. Where is the wastegate controller ? Can I look at it and tell or is it a buy a new one and see if it works thing? Any other thoughts would be greatly thanked, this is damn annoying and would love to get it fixed now

boost leak.

Ok, boost leak? Any suggestions on where to start looking? The boost goes fine up to 4~5 lbs, then it's like it hits a wall, the boost goes to 0 then because I let off the gas more of then it just going to 0. sorry if i explaned it wrong, but it almost like it will just buck if i stay in the gas.

I was just reading on one of the troubleshooting pages, and it's seems if the Double Throttle Control isn't working then your boost is supposed to be maxium of 5 psi, how would i check to see if this is working properly?? Is it just a simple take the elbow off and full throttle and it should open the double throttle then or is there something else to check??? thanks.

Here's a real simple and quick way to do it. Turn on the car, make sure it's warm. Pop the hood. Stand to the side so your face is away from the bay as much as possible, and use the throttle adjustment thing to rev the engine (hard), to make boost. If there's a boost leak from a split hose/tube etc, you'll hear a gush of air coming out. Obviously, repeat as necessary until you isolate where the boost leak's coming from, or at least you can narrow it down to a very small area. I got lucky...I actually FELT it hit my face lol. Loose coupler. Another friend had the same thing, but it was the stock accordian-type IC hose that had split, on the underside. Can't see it, but can still hear it. That'll save you lots of time IMO.

The good thing here is, the car only makes 4 - 6 psi in neutral, so you won't have to worry bout hurting your turbos while making such small boost. Holding the throttle open while in gear/in motion runs the turbos against a brick wall (as you mentioned earlier), causing them to spin at a MUCH higher rate than they're made to handle. Leads to premature failure.

Ok, ill try that today hopefully that will help me narrow this down. Although I have had a boost leak on the car before (where the y-pipe meets up a coupler wasn't tight enough) it acted nothing like this.

I'm wondering since there was some oil in the system from the blown turbo that had to be burnt/worked out after the used turbo's where installed, is there anything the oil could of possibly of clogged to cause this??

Thanks again for the ideas for stuff to check.

Thanks for the help guys, it ended up being a boost leak. I can't believe it i've never felt a boost leak like that before. It was the upper intercooler pipe to the stock elbow. One of those cheap clamps I tightened down to much and it got ate up and wasn't tight enough.

Glad to see you found your problem. Did ya see/feel the big swoosh of air? lol

Actually no woosh for me :(, I just got to see the intercooler pipes pulling on it and it didn't seem tight enough so tried to tighten and noticed the problem.