Need More Boost

87GNcospg

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Jun 23, 2003
i have the greddy profec b spec II controller. stock elbow and downpipe. lareger puck installed in the elbow. HD wastegate with the rod turned all the way in. T63E.

i can only get about 18-19 psi out of this thing. i dont have any exhaust leaks or vacuum leaks. greddy unit is hooked up correctly running about 100% :eek: . turbo seems to be in good condition.
what else am i supposed to check? :confused:
 
What do you mean the boost controller is running "about %100"? I know you said it's hooked up right but I would check the hookup on the solinoid/waste gate/controller. If I remember right the HD waste gate runs at about 19# so it might just be running at it's lowest level. Also what are the settings on the controller (gain, boost, ect.) Let us know. james
 
here are the settings on the Greddy unit.
set boost- 95%. gain 15-35, never really made a difference where it was set.
set gain is at 18 psi.

all connections are good. with the greddy unit at 0% i get about 18psi. did a few runs today and noticed that i can get 22psi. i think that i should still see a hell of a lot more adjustment room.
 
Try increasing the gain a little . Also, check the warning and limiter. If the screen is going red that means you're exceeding your upper boost limit and it will dial back the duty cycle of the solinoid however much you have the limiter set at. Let me know if this does anything and I'll look at my settings tonight to see where mine is at. I run 24#.
 
greddy unit is set to psi by the way. the gain is maxed out at 35. limiter and warning is set at 26psi.
i just dont understand why 100% set boost is only getting mef rom 18psi to 22psi.
 
Give the Greddy to me :biggrin: I don't think it is working..... I'll check it out and get back to ya! :wink:

Seriously...... you either have a wastegate puck not sealing off..... or something wrong with your turbo ... if all that other stuff you mentioned that was fine.... was actually OK....

Exhaust? Cat? .... plugged up exhaust?
 
Ok, first off my settings are as follows.
"set' is at 60%
"gain" is at 5
"set gain" is at 10.
These settings give me around 23#'s of boost. I'm currently running the stock turbo so yours will be different but I wouldn't think it would be to much. In fact, with your turbo being bigger and a HD waste gate I would think you would need less duty cycle fed into the set position.

Also, make sure the line from the waste gate actuator goes to the "com" port on the solinoid and the line from the compressor goes to the "no" port on the solinoid.

Let me know what happens. james
 
i did a lot of test runs on the greddy unit at every possible setting. vacuum lines are routed correctly to the valve unit.
i tried ,
"set' is at 60%
"gain" is at 5
"set gain" is at 10.

this netted me 20.5 psi. same settings but with "set boost" at 100% i get about 23 psi. only other thing i can think of is my turbo is about to crap out on me or i have a sock stuck in my intercooler :confused: . to sum this all up, my greddy unit gives me about 5-6psi adjustment range.
i took off the turbo elbow today to see how the bigger puck is sealing and it has PLENTY of sealing room. i also do not have a catalytic converter on my car. i am running a test pipe with an open dump
my always seems to have the "unsolvable" problems
 
That's odd. Do you have a manual boost controller you could use to verify the greddy unit is causing this problem? That would probably be my next step. You definately should not have a problem gaining boost (unless the solinoid is hosed) as the controllers only function is to limit boost. Are you using the "y" piece in vacuum plumbing anywhere? If so you shouldn't be. Also you could use an air compressor with a regulator to verify the greddy unit is working properly. Let us know. james
 
how can i use an air compressor to verify the greddy unit is working?
no i am not using the y fitting. i replaced all my intercooler hoses today because the old ones looked like they were in bad shape. this did not solve the problem.
i did notice that the rod from the wastegate is a little off center when it is connected to the swing arm on the elbow. the rod needs to be puilled out towards the radiator slightly for it to connect on the swing arm. ill try and take pictures tomorrow. would this cause problems?
 
i will also try a spare RJC racing boost controller that i have to see if i can get more boost with that. with no vacuum source going to the greddy valve unit my greddy should still display the boost reading since it is T'd off of the fuel regulator, correct? it is my only source of boost reference.
 
Yes it should still display your boost. As far as the air compressor goes if you use a pressure regulator you should be able to apply pressure to the greddy unit and see if it starts cycling the solinoid. Also you could apply pressure to the solinoid to make sure it's bleeding off air at the proper time. Basicaly just user the compressor/regulator setup to simulate the boost in your manifold. You can't set the boost for your car like this because there are other variables like your waste gait and the volume of air and such, but you can make sure the solinoid is cycling and see where it sends the air at different times. Also you can verify your gain, set gain, and limiter turn on positions. Just be sure to use a regulator because I don't imagine the boost controller would respond favorably to 100+ psi of pressure. :eek:
 
tested the valve unit with an air compressor and it seems to work just fine. i put on an RJC racing manual boost controller also. i had it cranked all the way and could only get about 17psi :confused: . my boost is going somewhere, just not in the motor.
im going to do a few more tests this weekend . . .
 
You could try unhooking the line to the waste gate. Then it won't open and you'll get the max boost possable. Just be carefull because you'll get the max boost possable. :eek: It could also be your waste gate puck not sealing. Just some thoughts. Keep us posted. james
 
Back to basics, I once had a similar problem with my stock turbo never going over 19 psi no matter what I did. After messing with EVERYTHING for about a month I finaly found an intercooler hose that was not seated properly and it would not leak under 18 psi but as boost went higher it would bleed everything else out under the hood. Just a thought....
 
NM Tom said:
Back to basics, I once had a similar problem with my stock turbo never going over 19 psi no matter what I did. After messing with EVERYTHING for about a month I finaly found an intercooler hose that was not seated properly and it would not leak under 18 psi but as boost went higher it would bleed everything else out under the hood. Just a thought....

i replaced all my intercooler hoses 2 days ago. i got them a little bit bigger so that they fit over the pipes more so they can be checked off the list. checked header bolts to see if their tight and for cracks. i took off my intercooler with a homemade duttweiler neck. i saw a few fins caved in from something coming up and hitting it. i then put another stock intercooler on hoping that the caved in one had a crack in it. no change. :mad:

im about to go unhook the line going to the wastegate. ill crank up the alky just in case :D
 
just back from driving around with the vacuum line disconnected from the wastegate. max boost is about 19psi.
not sure about what else i should do . . .
 
I would check to make sure your wastegate puck is sealing proberly. After that I would look for plugged exhaust. Maybe unhook it before the cat or something.
 
i took off the elbow (again) today to see if the puck is sealed properly. there is an equally spaced big carbon ring around the hole on the exhaust side of the turbo.
exhaust is not plugged. i have a test pipe and all these test are done with the dump open.
im assuming that after all these test my turbo is running out of steam.
last week i checked for shaft play and there was none. checked again today and there is a tiny bit. maybe less than 1/8 of an inch side to side. no in-n-out though. :mad:
 
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