Heres a good one, inside my forge dump valve I had a blue spring, now according to their site the values are as follows,

Green - 5-15 PSI

Yellow - 15-23 PSI

Blue - 23-30 PSI

Red - 30 + PSI

When forge refurbed it they gave me a red spring incase I wanted to change as they said most people put the stiffest sppring in. I have done this now trying to fix another fault.

What i dont understand is, Im running 1.2 bar which is around 17.4 psi. Surely I should only have a yellow spring would you not agree?

Im worried having these stiffer springs may be causing damage somewhere.

Cheers

Ben

 

I did have this worked out ages ago, but I've forgotten how it works now. But suffice to say, even with the wrong spring, it still works properly. A weak spring gives you part throttle problems where it's continually slightly open.

 

It isn't the boost pressure that opens the dump valve or you'd leak boost all the time, it's the pressure at which the valve dumps when you close the throttle.

Mine was too stiff which caused the airflow to stop, the MAF then read 0 so cut the fuel, OUCH ! A softer spring now opens easier and the MAF "jerk" has gone.

Yellow would be ideal, my service kit came with some shims you can use to raise the stiffness slightly. Mine caused problems after fitting a FMIC, but now seems a lot better.

HTH

DunxC

 

Cheers Ill get a yellow one and see what happens.

 

Yes Dunx explanation rings a bell.