Is it possible for a 10 psi wastegate spring to produce only 7-8psi? I am trying to figure out my TurboSmart MBC, the single stage one with the relay and in-cabin toggle switch. With the boost controller hooked up, the low (off) psi is only 7ish psi ( SHOULD BE 10 RIGHT ?) and with the switch on and controller turn wide open, It only goes to 14 psi. I want about 17-19 psi. Is it possible that my base wastegate spring is too small. I can use a homemade MBC and squeeze 16psi. I guess my next question is, If I put in a 13.053psi Green Tial wastegate spring will the MBC be able to boost more than 14-16psi, or does this sound like a turbo problem?
turbo is t3/t4 50 .48a/r
d16 engine

 

Someone help, I dont want to waste money on a Spring if this isnt gonna work

 

try taking your wastegate signal from the intake manifold, or at least after the intercooler, so that you have ~10 psi at the manifold and not at the turbo (there will be a pressure drop through your intercooler).

alo, if you use a 13psi spring, yes your boost controller should definately be able to go over 16psi. good luck

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eastbay92cx &raquo;</TD></TR><TR><TD CLASS="quote">(there will be a pressure drop through your intercooler).
</TD></TR></TABLE>

right

 

I have the lower port coming from the compressor port on the turbo. So you are saying to move it to the manifold instead?

 

yep. guarantee you will pick up a pound or two of boost. i was running it off my compressor then switched it to my intake and i picked up a full pound (7@COMP 8@mani)

 

I'll try it tomorrow, but I still think that I may need a higher wastegate spring. Any other info on why my 10 psi spring is only making 7 psi would be great.

 

you may have a boost leak somewhere. also if its an SSAUTO style wastegate that could be a problem those thing are sometimes unreliable

 

NO, ive already been through all this. I bought a Revhard drag mani, and made a boost leak detector. No leaks whatso ever. I can but another MBC on and squeeze 16 psi but i never turned it all the way down to see if it was at 10. I dont think this boost controller will boost more than 6-7 psi over wastegate.

 

The wastegate is Tial 38mm. I dont know why this setup wont boost over 16psi. The head is stock, no cam, just port and polish,do you think this is why.

 

it should boost more than 16 whether the motor is stock or not. unless the turbo is just too large for the motor it shouldnbt limit the amount of boost the car can make.

 

I moved the vacuum line from the compressor port to the intake manifold and did get 1 psi, but thats it. The turbo WAS a t3/to4e .50coldside/.63hotside. I had it rebuilt and lowered to a .50/.48 because it was only boosting to 12 psi, and taking almost to redline to make that. Now with the new.48 turbine it makes 15-16ish at 5000 rpms. A lot better than before, but I would have thought it would do more. Is there a way I can bypass the wastegate to see what kind of boost the turbo can make?? I am not worried about hurting the motor if I just experiment for a second or so.

 

yeah unhook the vacuum source going to the wastegate. then the wastegate has no way of opening. good luck with that

 

I unhooked the vacuum line for the wastegate and 16-16.5 was all it would register. So I guess that is all this turbo will make, right? Do you think that an intake manifold or a cam would help. I will probably do the Edelbrock manifold if it is worth it. What kind of power gains can you get from this? I know on a stock y8 N/A, the gains were about 8hp and 6ftq, I think.