You can type here any text you want

Low Boost? Help guys!

Welcome!

By registering with us, you'll be able to discuss, share and private message with other members of our community.

SignUp Now!

Esasky's85GN

RACE ME WITH WHAT?
Joined
Aug 7, 2001
Messages
529
Ok, so here is my issue:

Driving the car and decided to get on it. Car only spools to about 12 PSI and stays there. I am running a Turbonetics Deltagate wastegate on the car. Has the 9PSI spring and adjustment screw set it to 12 PSI. So, I figured that it was because of that. Hoses were hooked up as follows:

Pressure pickoff on turbo, T-eed to vaccum lines running to BOTH boost side and Vaccum side of wastegate. No boost controller.

Just to be sure, I pulled the wastegate off and checked the operation of it. Wastegate opens @ 12 PSI. Ok, that works. I got an LED Flashlight and shined it on the valve to see if it was sealing, and bingo, I could see light shining through the valve. So I am thinking this is my problem.

Well, Turbonetics does not support the Deltagate any longer and no one there knew if there was supposed to be a valve seat. So, I decided to machine the lower housing in attempts to "seat" the valve. Valve is seated better than before but still see light through it.

Question #1: If the two vaccum lines coming from the same pressure source (pick off on turbo) were connected to both boost and vaccum sides of wastegate, shouldnt have my turbo boosted to max amount that turbo can produce and possibly blow my motor? It didnt, only getting 12 PSI of boost.

Question @2: Can this small of a exhaust leak coming from gap in wastegate valve stop me from building additional boost?

No additional exhaust leaks are present. I do have a very interesting setup as the car is an 85 GN with an intercooler setup on it.

Please feel free to ask me any other questions!

Help is needed and much appreciated!

Thanks!

Chris
 
*Disclaimer, I'm not a mechanic.* Now thats I got that out of the way, I'm going to reply because I had a similar problem. Does the boost build and then blow off? Almost like a flutter? My car would build boost up to 10 and just hang for a minute and flutter then drop off. It ended up being a fueling problem. The tank was clogged with rust and the filter was jammed up too.
The next boost issue I had was my silicone coupler slide out from under the clamp on the throttle body. It was about a quarter inch pice sticking out allowing the boost to drop off. I would check fuel pressure and then use soap and water on connections.
 
Ohio,

No, its not really fluttering. It hits 12PSI and stays. I know my fuel is good because I can see the pressure through my gage.

I am going to check silicone couplers. I have quite a few of them on my setup.

Thanks for chiming in!

Chris
 
One other thing you could try would be to put a manual bleed (to atmosphere) after the T, before the bottom of the wastegate. This allows you the same pressure to the top of the gate to increase boost, but less pressure on the bottom of the gate trying to open the valve.
 
nothing yet. I actually just purchased another wastegate. Mine was not seating and I am not putting that back on. Once I get the new wastegate on, I am gonna see what happens. Thanks for your curosity! :biggrin: i will keep you posted!

Chris
 
Me too

I am also having a similar issue, but i am only building around 2-3 lbs (if you want to believe the crap gauge).

What is a good way to check FP under acceleration? Some day down the road I would like to have a cockpit gauge, but they are pricey. Mine is acting like FP.
 
nothing yet. I actually just purchased another wastegate. Mine was not seating and I am not putting that back on. Once I get the new wastegate on, I am gonna see what happens. Thanks for your curosity! :biggrin: i will keep you posted!

Chris

if your wastegate is not seating properly it could definitely be the culprit. It would be letting out the exhaust energy that spools the turbine wheel. It would also make sense that you ARE building boost since the leak is small, if the leak were bigger you boost much less. If you want to be 100 % sure weather its the wastegate or not and you have another spring for it, put a bigger spring on it and see what happens, if the boost rises, then it's not the leak. Please report back what happened.
 
if your wastegate is not seating properly it could definitely be the culprit. It would be letting out the exhaust energy that spools the turbine wheel. It would also make sense that you ARE building boost since the leak is small, if the leak were bigger you boost much less. If you want to be 100 % sure weather its the wastegate or not and you have another spring for it, put a bigger spring on it and see what happens, if the boost rises, then it's not the leak. Please report back what happened.
I went out tonight car built 12psi. Hung out for a while then drove to a buddies house and and was only building 5psi. It would shootnto 10 only for a second and then stay at 5
 
At this point I would disconnect the downpipe and see if the turbo exhaust wheel is still there....
 
Back
Top