Trouble trying to get more boost out of her!

[richy rich]

Well My 87 GN has an adj. rod[49 turbo]and a older RJC[I believe thats what it]adjustable thumbwheel
hooked up to the vacume lines running off the turbo.
When I unscrew the the thumbwheel,it should have more boost!Butthe boost doesnty change wether its turned in
or out 3 whole turns?So I turn to the adj. rod-I shorten the rod and ya I have more boost but its not one turn for a pound
its like 2 turns for a pound??Maybe more!Its wound in pretty far and real tough to get it hooked on the wastgate arm.
Now my buddy has the same thumbwheel,his is hooked up the same as mine.his is mint[i should just borrow his but hes far away and its a pain!]
Im now getting about 16-17 lbs but like i said the rod is real short!
Oh and I have a couple lbs of boost creep in high gear!
K so im thinking either my thumbwheel is pooched or my actuator has a hole in the diaphram.
I wanna go the track,install my racechip and turn up the boost!But need this lil problem delt with first!.
So wadda guys think??

 

[Chuck Leeper]

Try checking the exh system back pressure.
Manifolds cracked?
Boost creep>> Check the housing hole for size vs the puck .
Is the puck closing?

 

[richy rich]

Manifold is not cracked.How do I check puck?

 

[BlackBandit]

you said thumbwheel hooked to the vacuum lines? I would adjust your wastegate back to where it had about an 1/8th inch of pull and figure out what's going on with the thumbwheel deal. If it's a bleeder then out should increase boost. If it's a MBC then in should increase boost. If it doesn't have a vent port it's most likely a MBC.

EDIT: FWIW if you have a bad diaphram in the wastegate you would probably be seeing an overboost condition as your boost referance wouldn't push it open as easily.

 

[richy rich]

Ya its a single line in thumbwheel deal!
And buddy who has the same one says turning out increases boost-I tried both ways??

 

[DaySleeper]

I'd get rid of the thumbwheel for now and just turn the adjustable rod in a few turns and see what you get. Should be plenty if it is working right.

 

[Chuck Leeper]

Manifold is not cracked.How do I check puck?

Pull the down pipe off, and look at the carbon ring around the housing hole..While U R there, check to see that the puck shaft is not binding, and the puck is floating on the mount.
Take the boost controller out of the equation by hooking the boost line from the compressor directly to the actuator...Should see boost at around 13#. If so, the actuator is ok.

 

[richy rich]

Take the boost controller out of the mix-thats a good idea!
BTW My rod is pretty short and tough to get on the arm,[that sounds bad]and I wanna go to the track and turn the boost up,
and Im reading that with the longer rod and the thumbwheel all in good working order,and using that to increase boost,the car will spool up quicker,
and not have boost creep.

 

[bison]

Run a heavy duty actuator. Be sure the wastegate hole is covered.

 

[GNVYUS 1]

Uh this is pretty easy

1) It's a Manual Boost Controller, when you screw IN the screw it RAISES boost. You said this

When I unscrew the the thumbwheel,it should have more boost

No, adding pressure on the internal spring raises pressure, unscrewing the knob or screw releases pressure.

2) 1 turn doesn't exactly equal 1psi, usually 3 turns is 2psi but that seems to be fine on your setup.

3) It spikes because you need to open the wastegate hole on the turbo housing and smooth out the edges inside it.


Problems solved.:wink:

 

[richy rich]

Well the puck is fine,And I pressure tested the actuator-all is good.
I got rid of the thumbwheel and ran the line to the orig boost solinoid thing that sits on the pass.valve cover[forget the name of it]
I went back to old school of shortning rod for decent boost.Im gonna try another adj. thumbwheel.The Turbo Smart Part Number BLACK: TS-0106-1002.
I dont know if its the best one on the market but,
its avail.locally.