Basically im hitting full boost of 13lbs on my 5431b and it is tapering down to 11 by redline... it also tapers down slightly lower when doing back to back pulls, leading me to think there is a heat related issue... i have no vacuum leaks or exhaust leaks.. is my wastegate the cause of this?

b18c1
inline pro log
precision 5431b
3 inch dp back
tail 38mm 10lb spring
hks ssqv
precision 650cc
neptune
manual boost controller

 

what type of boost controller do you have? how do you have your WG vacuum lines ran?

 

Eliminate the boost controller & run the car on the wastegate spring.
See if the issue occurs on the spring pressure only.

 

Can you post pics of the setup, and a graph.

Want to put together a very similar setup and want to see the fitment.
Thanks!

 

a line is ran from the compressor housing to the manual controller to the wastegate

 

What type of controller... Have you bypassed it?

 

http://www.xenocron.com/manual-boost...ler-p-267.html

im getting my dyno info from the wastegate spring pulls to see if it faded on them. i should have them tomorrow

 

i took apart the wastegate, and the diaphragm and spring are in great condition, but is where im getting confused, the spring in it was the large green spring, which is supposed to be 13.05 psi, how were we able to do runs on 10psi if it is a 13psi spring? the car has always had the boost controller hooked up, we have never run it with a line straight to the wastegate. is there someway the boost controller was able to make it run 10psi? im very confused now.

 

i imagine pressure loss through the system (although 3 psi is a bit much)

 

i was told that back pressure in the short log manifold could make the 13psi spring open early...

 

at what rpm are you getting full pressure?