Hi Guys..

I've got my Forge Evo-15 (multiple spring swapable, recirculating) BOV and i fixed both the semi-stiff spring and later the stiffer spring... Although i am not able to boost much (not tuned till next wednesday), i did some runs:

1) The stiffer spring made the car jerkier when i released boost, and the BOV was whistling much more (and i really mean a whistling sound: Tooow-tooow-toow...!!)

2) While the semi stiff spring was less jerky when i released pressure and producing a long PSSSHhhhhhhhh noise when i released boost..

Which of the springs is better according to the above observations!

Thanks and any other instruction/comment welcome!

Wael

 

It's going to depend on how much boost you want to run. Stiffer is going to have less driveability but hold boost better, and it's the opposite for the softer springs.

 

So it's a matter of choice.. I thought the stiff spring would be harmful to the turbine.. I guess I'll leave the choice to my tuner (I'm aiming at 28psi)

Wael

 

for 28 psi your going to need the stiffer spring(red spring) and 2 shims in it to hold it best it will cause it to have partial throttle flutter jerky as you put it but it will work best for your application. the best thing to do is let the throttle go completely. but it works best this way we have done dozens of them at 30+ psi.

 

+1, it will cause compressor surge if you try to do a lot of part-throttle accelerating and/or letting off before building enough boost to open the BOV fully. YOu have to learn how to do a full release of the gas so that the BOV can chirp instead of flutter.

 

Ok, i understand what you mean.. I'll be getting on getting used to it once the setup is done.. Thanks a lot!

Wael