I'm running a brandnew HKS 50mm racing wastegate with a brand new 10psi yellow spring. I have a purple 14.7lb spring on the shelf. When I had my car on the dyno, the yellow spring would'nt start venting until 14psi. So I figured the wastegate was binding up. I removed it, and checked it out. No binding or anything like that....but what I don't understand is why won't it vent earlier? I have maybe 100miles on it, do these springs take time to heat cycle and get weaker? Anyhelp would be helpfull. CJ

 

Are you running one vacuum line on the lower fitting?
Where is this vacuum line going to on the intake manifold?


-Ted

 

I'm running a vacuum line from the uim, to a profec B, then down to the mid section of the wastegate. The aluminum section has a fitting in it, but its vented to the atmosphere. Ari, at RP said to run it like a external wastegate, so thats the way we had it hooked up. Setup this way, it controled boost fine, but I'd just like to get it down to 10psi. 340rwhp on a mustang dyno is a little to much for daily driving. CJ

 

Contrary to common belief, the spring can have different psi ratings for the same colour.So a yellow spring can be rated at two different poundages.
How? because i've had two brand new hks race gates both with yellow springs but different ratings.
One was 10-14 the other 14-17 or there about.

 

My 10# spring in my HKS wastegate also opened about 14psi. I ended up using a spring from the standard series wastegate. Works great that way. The springs are interchangeable. Perhaps buy a 7 or 9# spring for the standard series.

 

Have you tried running the vac line directly to the wastegate? Take the boost controller out of the equation.

Marques