Hi all, i drive my FD with T78 GARRETT at about 18Lbs. boost with 8Lbs. spring and Profect "B".
My question is:
where is the advantage to put 15Lbs. spring
in my wastegate at the place of 8Lbs?
Any advantage?

 

I used 2 different spring in my car and here is what I noticed.

With the stiffer spring the turbo spooled much sooner and was more responsive. I was running 26 psi and the two springs I tried was teh 12.8 spring as well as the 18.5 spring. The 18.5 was much better by the seat of the pants.

If you can live with the higher base boost - go for the stiffer one.

 

Thanks Jim Swantko, at 26Lbs. the car come to flight?
Where is your setup and 1/4 time at this boost?
Stock apex seal and corner seal?

 

Haha, Jim doesn't have apex seals anymore....he went to the dark side....(read Toyota Supra).

 

Any guys know the stock corner seal on FD is good for
how many boost.
I broke one but my boost guage stop at 20LBS i don't know where is the boost when corner seal broke.

 

Yeah, I think thats pretty much it. The higher spring force wastegates will stay closed with more force, but you won't be able to turn the boost down to below their setting. i.e., you can't ever have less than 15 lbs of boost (at WOT of course) with a 15lb wastegate spring.

 

if ou have a boost controller then it should not move period, the vaccume lock should keep it closed , if not hen you have a poor design on your wastegate or a leak. I leave a .4 bar spring in my wastegates when using a controllerand thier is no creep or bypass, the lower spring rate means that if something in the system fails then it falls back to a much lower boost setting automatically. I use Tial BTW.

 

It's right PPC-RACING i check my wastegate and i have leak ( hole in diaphragm ).
I understand why low boost in first and second gear ( 12 and 14 Lbs ).