Can't raise boost?

[codez]

Hey guys

I have an 86 GZ20 5 speed, with ARC front mount, BOV, manual boost controller and boost gauge.

I have adjusted the boost controller so many times already and its to the point that i cant wind it out anymore, and i still cant get any higher than 10 PSI max in 3rd gear and only gets to like 8.5 - 9 PSI in 2nd.

I'm thinking i must have a boost leak somewhere, I am pretty sure all my clamps are tight but will check again tomorrow to be sure.

Just wondering if there are any other explanations as to why I cant get any more boost?

Cheers

[pandaah]

would definetly be worth checking for an intake leak...

but these are also some checks you should do (even tho they may be silly questions)

- check the t-piece is around the right way
- check the vacuum lines on the wastegate actuators are not damaged on BOTH turbo wastegates
- check wastegate condition and whether they both open at the same pressure
- check turbocharger condition
- finally, if all other tests pass... check for blockages in the exhaust system

[codez]

thanks for the reply pandaah

i will check the intake and the vacuum lines tomorrow and also check all my clamps.

are you talking about the t-piece my boost contoller is joint to?

also how do i check if the wastegates are opening at the same pressure? (may be a silly question but im new to the world of turbos lol )

[pandaah]

nah im talking about the T-valve you use to adjust your boost... there are two wastegates on the 1ggte and you need to t-piece both lines and run the 3rd nipple from each t-piece into each other, and then t-piece the new vacuum line and hook it up to the t-valve boost controller, and the other side to vacuum behind the throttle...

to check your wastegates, put a vacuum line from a hand held brake bleeder pump, and the other end on the wastegate and pump them with pressure until the wastegate actuator rod moves, check what pressure it opens and make sure both wastegates open at the same pressure

[codez]

okay then, ill be able to have a look at the t-valve lines and hopefully find out whats going on

but dont have a brake bleeder pump to check the wastegates so hopefully i narrow it down to something other than that

thanks for your help mate! + rep added

[pandaah]

yeh you could also just pull the wastegate actuator rod and make sure wont isnt stuck open or something, make sure they both are hard to pull and snap shut by hand etc.. =)

let us know what you find!

[codez]

yeah no worries will post up my findings tomorrow night, thanks again mate

[TRDcelica90]

also when u test it please wind ur boost back down lol..

if u had an induction leak i wouldn't think u could get 10psi.. i could only get 4 or so

[woggin]

if its just a loose clamp, it will just bleed the boost, the car will also run like a dog(on boost) due to the AFM registering soo much air, yet none of its getting into the motor!

are you sure you have both actuators hooked up correctly?? When i did it on my gz20 i blanked the factory compressor housing nipples and took a feed directly from the front of the intake manifold, had it on a t-piece then split the outlet line from the boost controller to both actuators!!

what kind of boost controller you using?? (GFB, TURBOTECH, TURBOSMART???)

[pauljones1976]

I had the same problem but mine turned out to be the external wastegate controller (diaphram). The spring had become less tensioned and would open the wastegate at about 10psi. I replaced the actuator with a better one but still had the same problem. Bent the rod for another 1psi. I solved the problem temporarily with a couple of springs.

[codez]

also when u test it please wind ur boost back down lol..
if u had an induction leak i wouldn't think u could get 10psi.. i could only get 4 or so

what part of the intake was your leak in mate? and i wont forget to do that lol

if its just a loose clamp, it will just bleed the boost, the car will also run like a dog(on boost) due to the AFM registering soo much air, yet none of its getting into the motor!

are you sure you have both actuators hooked up correctly?? When i did it on my gz20 i blanked the factory compressor housing nipples and took a feed directly from the front of the intake manifold, had it on a t-piece then split the outlet line from the boost controller to both actuators!!

what kind of boost controller you using?? (GFB, TURBOTECH, TURBOSMART???)

not sure if its hooked up correctly or not, my mate who i bought the car off hooked it up for me. the controller i'm using looks the same as the GFB ones..
I havent noticed the car running bad on boost.

I had the same problem but mine turned out to be the external wastegate controller (diaphram). The spring had become less tensioned and would open the wastegate at about 10psi. I replaced the actuator with a better one but still had the same problem. Bent the rod for another 1psi. I solved the problem temporarily with a couple of springs.

okay mate cheers for the info!

[Kedderz]

If you have a leak you should be able to hear it sucking in the extra air, also being a AFM metered car, it will run rough due to the extra air being sucked in after the AFM.

[Shifty]

are you winding it IN or OUT?

[codez]

i am winding it OUT?

if im doing it wrong then i am a retard lol

[TRDcelica90]

dont u wind it in to increase the spring pressure lol??..

that is if its a ball n spring type..

intake leak= before turbo.. split hose..