PROBLEM:
I just recently built my motor and when we were tuning it as we turned up the boost eventually up to 16psi it seemed as if 1st and 2nd gear dramatically would not hold this boost. 1st gear will hold around 8psi, while 2nd will spike about 14 and hold 10-12 and even third will spike 16 and then only hold 14 and sometimes i have noticed at high rpm it will lost a 1 or 2psi in 3rd. While 4th and 5th are pretty strong holding 15 to 16 lbs.

SETUP:
I have a 38mm Turbonetics Evolution Wastegate with a 7psi spring in it, running a Greddy Profec II electronic boost controler, t03/t04 .57 trim with a log manifold also with a turbonetics raptor blowoff valve. Yes i know that this is a reasonably small setup but it should def hold that amount of boost.

I checked all couplings and vacuum lines, everything is good, the blow off valve is closing and opening properly under boost pressures but not sure about pressures that high. The turbo is in great condition with no leaks or any play in the turbine wheel.

My guess I was going to try is going with a bigger wastegate spring, could that be the problem? if so do tial 38mm springs fit the 38mm turbonetic evolution wastegates? Or is it my boost controller? Any ideas or imput is appreciated thanks guys!

 

You may not setting the boost controller correctly. Make sure that the SET and the GAIN settings are not too close to one another. Also, ensure that the START BOOST setting is over .65bar or so to get it to go to 16psi. The boost controller will do more than switching springs.

Also make sure that the boost controller solenoid doesn't have too many "Tees" off to something else. "COM" port should be connected to the top of the wastegate, while "NC" should be set to the bottom nipple, with only ONE "Tee" off of to a strong vacuum source like the intake manifold or vacuum block

That should do it.

 

ummm ok, i know i have a vacuum line off the boost controller running directly to the wastegate itself however the other vacuum line off the wastegate is T-ed with a vacuum line from my turbo and my blow off valve then is routed to my intake manifold. But i doubt there is a problem with this, its all a direct vacuum source?

However i will check my settings on the boost controller again but what i know is the SET is at 1.1 Bar, the gain is at 35%, the low initial is at .2 Bar and the limit high is at 1.15 Bar. I don't see what is wrong with these settings but please correct me if I am wrong?

And I just keep reading specific things on wastegate springs that they can only handle up to so much compressed pressure before they give, depending on your wastegate size, spring, and turbo size no matter what kind of boost controller.
But Thank you Shodan, any other ideas?

 

anyone? thanks

 

first i would turn the ebc off and make sure the car holds 7psi through the rpm range. if not then look into why. if it is holding steady then it looks like the ebc settings need to be adjusted.

i would turn the start boost to 0, that function helps spool time and should not effect consistency. use the SET to reach the desired boost and GAIN to fine tune consistency. once thats good, then you can play with the start boost to help the spool time.

the profec-b II took a while to get used to for me but i liked it alot once i was using it correctly

EDIT: im pretty local to you, i'd be happy to help if needed

 

dpetro1 Thanks alot, i did try to just turn the ebc off and it holds fine with just boosting off the 7psi spring, I will try to mess with the settings some more, thats kind of the approach i took first but maybe i am still missing something.

Do you think it could be the spring? I have been trying to search for people running the evo wastegate more than 12psi to see what spring/turbo/ and boost controller setups people are running but I can't find anything?

 

a 7psi spring should be able to hold 16psi with no problems. not sure about how reliable a turbonetics gates are, hopefully thats not the problem

 

ummm ok i was thinking the same thing, i just ordered a 9si spring and some shims i am going to play around with that and see if that makes a difference, i kno these wastegates are capable of handling 400+hp but im guessing if all the offered was the 5,7,9, psi springs then maybe they weren't built to handle that much boost.... but thanks again!