Hey guys,

Am after a spot of advice.

My 99 classic is currently running 358bhp at 1.5bar on a vf34 with all supporting mods.

The standard sump valve was removed prior to mapping and the intercooler was plated. So I am running bov-less.

My question to you guys is what boost pressure does the standard sump valve crack open at, because to get rid of the spluttering/compressor stall on gear changes I want too fit the standard recirc back on, however I don't want too fit it if the valve cracks open and dumps my boost.

Any help would be much appreciated.

Sp00ks

 

A properly working standard recirc valve will not dump any boost at even 40psi of boost. It only opens when there is a pressure differential between the intercooler and the inlet manifold i.e. when you get off the throttle.

So fit it, you won't loose any boost.