Need More Boost!!!!

[Red87GN]

Help guys,
I'm pretty sure this is a newbie type question. But I have searched for hours and haven't found a specific answer to my question.
What are all the possibilities to look for for a low boost problem?
I have checked the following: all new vacuum lines, feel good about exhaust not having any leaks, adjustable boost rod is as short as it will go. I've just plu run out of places to look. I have thought about getting rid of the stock boost controller and putting the Dawes valve on. Also is there a test for the wastegate controller?
Any help would be great. Thanks in advance.
John

 

[scottyb]

What boost are you getting and what is your target?
Turbo?
details.....

 

[87grandnat]

yeah, whats the most boost you are getting?

 

[ijames]

Far and away the most common cause of low boost is having the restrictor tee in the Y hoses going from turbo compressor to actuator and solenoid pointed wrong. The leg with the restrictor should go to the turbo compressor outlet. It doesn't matter which of the other legs goes to actuator or solenoid.

 

[Ryan87GN]

Easy fix man.-

Just get a hacksaw, cut a little off of the wastegate rod( maybe 3/16") then get a grainger valve. Make the rod as short as it will go and crank the grainger all the way shut.

If you do this right you'll get about 45psi boost like I did .

Be careful with a grainger valve if you go that route.

HTH,
Ryan

 

[QuickWE4]

Still running the stock DP? If not, check to see that the puck is sealing properly. Pull off the dp and look to see if the carbon ring around the hole is off and that will tell you if it's not sealing properly.

If you're running the stock setup, then I've just wasted your time with useless advice

Did the problem just start? Did you mod anything prior to the problem starting?


Rich

 

[Red87GN]

Low boost problem!!!

When I got the car running, the boost was at around 11 psi. I shortened the rod and got the boost up to 14 psi. The one turn per pound was working great and then it just quit climbing. I had plenty of rod left to shorten at that point but with no response to shortneing the rod. I am running everything stock except for AFPR, adjustable wastegate, and I have a Joe Lubrant 112 chip. My o2 are reading perfect right around 780-800 with little or no knock retard. I have a good fuel pump(walbro 340). The o2's tell the story that I'm not lean. Just not getting the boost I want. I suspect the gadget on the valve cover stud!!!!! Not sure what it's called. Also how can I check the the waste gate vacuum modulator itself to see if it is working properly. My thinking is that it is at least opening or I would have an overboost problem right?
Anyway I've had the wastegate and downpipe off and it seems to be sealing good. All stock config.

My target boost when I started was around 20 psi maybe 21psi. But I would settle for around 19 or so.

I have checked the y restrictor many times. What I haven't done is change the y restrictor. Do you need the y restrictor with a Dawes/ Grainger setup? Thanks a bunch for all the replies thus far. I know this car will fly once I get it lined out.
John

 

[ijames]

The Y restrictor doesn't go bad but most guys change it because the hoses do go bad and you can get that set of molded hoses and Y already put together. Yes you need the restrictor (installed closest to the turbo compressor fitting) with any kind of bleed valve setup, including the factory wastegate solenoid (that doohickey on the valve cover). The solenoids do go bad sometimes. First, you should have the hose from the Y going to one nipple on the solenoid and either nothing or that little foam filter on the other nipple. If you cap the second nipple off you get low boost. Unplug the cable to the solenoid and check it with an ohm meter. It should be about 70 ohms. Pull off the Y hose and put a hose on it and try to blow through it - you shouldn't be able to at this point. Then ground one pin on the solenoid and put 12 V from the battery on the other pin. You should hear a little click and now you should be able to blow through it at least some.

 

[Red87GN]

Boost is HERE!!!

Alright I now have boost boys!!! I put a relief valve in from the Gus Mahon description and it works great. The boost jumps to about 20 and settles to around 19. I think I can get rid of that spike by tweaking the ros on the wastegate controller and relief valve together. I have slight amount of KR about 2.5 deg and my o2's are at 769 on the last pull so I'm gonna put about 1-2 more psi of fuel pressure in her and go to the track next weekend.

Whew hew!!!!