cannot boost past 7 psi, wtf??

[superiorsupra]

I have had this problem for a while now, I can't seem to raise the boost beyond 7 psi. When I turn the boost up, it seems like the gauge would go past 7 or so for a second, then drop back down. The car feels like it is lagging once this happens, but runs excellent when the boost controller is off and boost is left at stock level. I have checked all the intake pipings for possible leaks, and changed all of the vacuum hoses, but am still having this problem. I thought it could be my HKS evc-ez boost controller, so I switched the unit with my bro's, and it still does the same thing. I then took the boost controller off and shimmed the wastegate with 4 washers and still the same problem.
The car has a ct-26 60-1 trim upgrade, with venom 550cc's, along with a lexus afm. Could this possibly be because of a exhaust leak? Any information would help. Thanks.

 

[starscream5000]

What kinda exhaust are you using? If it's stock, then I'd say some of the problem is right there, get a new down pipe (with an integrated elbow) and full 3" exhaust if you haven't done so already.
Is the vacume lines on the boost controller hooked up correctly and on there tight? Did this boost higher b4 or you put the controller on and can't get any higher than what it's at? Also get an aftermarket boost gauge, the stoker's a POS. Don't relly on it for accurate numbers.

 

[xarewhyayen]

you probably have a restricted exhaust/cat or something, if not, do you have any codes? look for that infamous boost leak code haha 34

 

[superiorsupra]

Thanks for the replys. I have a suprasport hi-flow turbo elbow with a hks downpipe and a stock cat with a custom 3-inch exhaust system. No engine codes, and I do have a aftermarket boost gauge.

 

[dbsupra90]

recheck the vac lines to and from the solenoid. also, you might want to check the actuator on the turbo. it could be weak, bent rod, etc. another thing to check is the turbine housing. the area around the wg flapper often get cracks and causes irregular boost response.

 

[suprashy]

(1) How 'bout the BOV flange. If that's not secure it could leak. In fact, how's your BOV?

(2)U said you switched the Boost controller unit, did u switch the solenoid too? Its your bros car, I'm sure he wouldn't mind. That would def. rule in/out the solenoid.

(3)Also, a DaveB also suggested to visually ck. to make sure the inj. grommets are seated in the head properly. Just take a nice light and shine it in the area.

My hose coupler had a tear in it (still didnt' solve my prob ), but u may wanna ck. those too. And also triple ck. your clamps and quad. ck. your compressor outlet hose. Good luck!

SupraShy

 

[Jaguar_5]

Try running without the stock cat, it could be clogged

And do a boost leak test (you can make one with a cap the size of your pipes, an air hose fitting, and a compressor with a regulator

 

[rumptis]

^what he said