Tired 14b?

[cyhm]

Hey guys, my gvr4 has been severely underboosting and been very inconsistent. I have a hallman es mbc cranked all the way up and it will only peak 15psi randomly (If it's lucky. Most times it's more like 12psi tops) and taper down very quickly from there. It also hits a lower peak boost each subsequent gear. For example if it peaks 14lbs in first gear, it might be 11 in second and 8 in third. Vacuum is good, and it does not misfire.

I have tried running no boost controller and then it would only peak 5psi max. I did a visual boost leak check and tightened all clamps, etc, but have not pressure tested it yet. I am going to pressure test it whenever I find an appropriate sized coupler, but right now I'm thinking either the turbo is beat or the wastegate actuator is worn out.

Any ideas?

 

[JusMX141]

Unhook the signal line from the actuator altogether for one trip and see what it does. That will rule out whether you have a faulty actuator or something in the boost controller has gone haywire.

 

[Boost Demon]

Always good to do a boost leak test as well.

 

[cyhm]

Boost leak test is a definite, but due to the inconsistency, I was leaning towards something else. I guess I haven't dealt with enough boost leaks at low boost/hp numbers to make a judgement, but the fact that the more I run it through the gears, the less it boosts, makes me think its not a leak.

 

[WES_393]

I am going to pressure test it whenever I find an appropriate sized coupler, but right now I'm thinking either the turbo is beat or the wastegate actuator is worn out.

The inlet is about 2.25". If your looking for a place to get that size coupler or leak tester, check out siliconeintakes.com.

It sounds like the wastegate might be staying open between gears. As if the actuator is getting hung up and/or the MBC isn't bleeding off the line pressure. So I'd go with what Jus said and try removing the line altogether. But my money is on a bad actuator.

 

[cyhm]

I will have to try taking the line off entirely later. Sorry if my OP was a little wordy, but I did try it with the mbc out and it would only hit 5psi max, so I am putting money on the actuator or entire turbo as well .

Turns out the actuator is shot. I have another one laying around, but I'm putting an hta68 in soon, so I guess I'll just deal with it being super slow till then .

 

[JusMX141]

Why's that? Swapping actuators is a 10 minute job!

 

[cyhm]

I was being lazy, but since then I got bored and found motivation to do it . Helped quite a bit, but I leak tested it, and my tb shaft seals are shot and a lower injector seal is leaking. So I'm still having some boost leak issues, but atleast the wastegate closes now.