Adj wastegate won't increase boost??

[tpabayflyer]

I have an 87 GN with a stock replacement turbo that has the adjustable wastegate rod....no matter how I adjust it it, I will not get more than 15 PSI boost.....If I shorten the arm, it just seems to spin the turbo faster at a give speed but it won't boost more than 15... I have the usual minor mods running red stripes with Jays street 93 chip... The car runs real nice but i would like to run about 2-3 more psi boost.... anybody know why I can't get more than 15??? does it require a chip change?? thanx in advance.. TBF

 

[ChrisCairns]

The turbo header flange will warp over time from the heat and when you put on a new turbo with a perfectly flat mounting surface it'll leak.

See if you can stick a feeler gauge between the turbo mount and the header flange on all three sides.

 

[ES1]

You might have the hose from the solenoid to turbo - acuator incorrectly hooked up and I also think there were some problems with some Y fittings in the same hose.
I think I remember it as being straight hose to turbo, Y to the acuator.

 

[UNGN]

Physically measure the distance from the face of the actuator to the center of the hole (with the rod off the puck arm) and tell us what that dimension is.

Rotate it shorter 3 full turns (it should be .150" shorter) and try that.

If you have a pre-turbo leak it will more than likely spool slowly so I don't think that's your problem.

 

[tpabayflyer]

thanx guys.. I'll take some measurements.... AS far as the hoses being misrouted.. that could be as i did replace them after the original ones started to crack...and when they did, the engine would boost uncontrollably .. it would happen in a split second so I know this thing can give me more boost... I have all the normal fuel system upgrades and I would like to tune this thing for about 17-18psi...I have a boost gauge on the car and it works well....I also don't have any exhaust leak at all....thanx TBF

 

[tpabayflyer]

I should also mention that I have rotated the arm from 3 to about 20 turns shorter and it had no effect on total boost.. all it did was spin the turbo faster at a given rpm.... TBF

 

[salvageV6]

Check all your intercooler and throttle body rubber hoses.

I had one that made a perfect 15psi. wastegate on my car.

Rock solid boost control too no matter where I set the rod.

Took me about 3 months to find the offending hose and reclamp it properly.

Could be something to look for.

 

[turbosam6]

I agree with the ic hose, you must have one torn or loose or something.

 

[charlloots]

do you have a cat. on the exhaust?

 

[TurboDave]

Originally posted by tpabayflyer
I should also mention that I have rotated the arm from 3 to about 20 turns shorter and it had no effect on total boost.. all it did was spin the turbo faster at a given rpm.... TBF

Are you rotating the "WHOLE" arm or just the threaded end??

I know, I know, stupid question, but I gotta ask, and cover all bases.

 

[tpabayflyer]

thanx again.. I am only roatating the adjuster part and not the arm.. it is closing the distance so I think I am doing it right....I have just put new hoses and clamps on and they are tight.. no leaks...I also removed the intercooler and cleaned it out.. I pressurized it and found no leaks at all....... I bought this car new and it is in real nice shape so I am at a loss. TBF

 

[salvageV6]

The cat. and exhaust could also be a limiting factor as previously mentioned.

 

[tpabayflyer]

I yanked the cat off 15 years ago!!! ..... exhaust is a BGC big elbow mated to a mandrel bent 3" homemade downpipe..... as I mentioned before, the vacuum hoses came off a couple times and when that happened the motor boosted to well over 25psi in a split second and died.... no damage was done so I was very lucky... this proves to me that the car CAN boost higher....
TBF I also measured the distance from the wastegate lever to the wastegat itself and it was 5 1/4" shutoff...

 

[salvageV6]

If you have a good stretch of road you can always pull the actuator line off and plug it and hope you can stop at 20 psi. or so with the throttle, as a test of exhaust and intercooler plumbing and the downpipe puck sealing etc.

If you get the proper boost with no actuator that would eliminate a lot of things.

One of those "Be Careful" type tests however. Might want to try a gallon or two of xylene in the tank for it.

That's what I would try next.

 

[tpabayflyer]

I know that the car will boost very high if I do that.... will higher octane allow the chip to give more boost?? I hate to run racegas as it it fouls up the oO2 sensor.. TBF

 

[salvageV6]

In that case I would think it would be in the hoses, orifice, or the wastegate solenoid.

 

[UNGN]

I'm going to guess it's the BGC elbow. Some people have had puck stick and boost control issues with them. It could be the puck won't cycle (it opens but doesn't want to close easily)

I would try a different chip, first, though.

 

[GN ERGY]

I have the BGC elbow on my car and when I switched turbos it wouldn't seal correctly, it would get caught at an angle and not seal the wastegate hole until I shimmed it and didn't have that problem anymore. It was an intermittant problem that happened on and off.
Tarey D.

 

[ULYCYC]

I have a Bowling Green 3" elbow that I use as a door stop on my garage. It handles that job great Check the elbow and puck...