When I first got my kit it had the stiff spring in it..and I swapped it out for the light one to keep surge down and wear on Turbo... now with the light spring my bov stays wide OPEN at idle and of course closes as vacuum gets to 0 and then boost builds... I have no trouble boosting and it spools fast. But...... here is a theory where this may hurt me.

At launches... I can't leave on boost no matter what.. I'm thinking that the bov being open so easily with the weak spring that boost is bleeding out while trying to stall truck! Where as if bov was closed at idle like on stiff spring it would start building boost much sooner while stalling truck? Hope that made since somewhat LOL and could this be an issue?

 

Unless you've done something odd with your boost reference line to the BOV, your theory would be impossible. The reference line also sees boost when the turbo spools, so it should help keep the valve closed to prevent boost leaking out.

What exactly do you mean you can't leave in boost? Does it break loose first?

 

i run the stiff spring and get no surge. even w/ light spring it should be shut while building boost. it shouln't build boost any faster w/ stiff spring.

 

Yeah It breaks loose well before reaching boost... yeah I agree that it will close while building boost.. but I'm curious to see if it is staying open while Im trying to stall the truck since I never reach close to 0 in hg? May have to get buddy under Hood LOL while I stall it up!! But I'm curious if that is not my problem then what benefits does a light vs stiff spring have? Mine is obviously really light because it is wide open at idle.

 

Valve will be close once your vacuum is below the springs tention. Pushing through has more to do with the brakes not able to hold the power you are appling.

Simple test for you. Open the hood and have some one watch the bovwhile stalling.

 

throw the stiff one in, see if it helps

 

my wife likes the stiff one better too. lol

 

I ran a softer spring than the one the KB cam supplied with. Never had a problem with it opening early. As long as your reference line is not kinked or something and its coming from the manifold, the force due to air pressure will be the same at open throttle. Then spring pressure will hold it shut.

 

So some run stiff springs And some light ones.... some bov are closed at idle..some are open? So What is the benefits of running one spring or another..

 

I just put the softer spring in to get a better bov sound. the stiff spring would give that pshhh sound. but i dont think i can stall my truck in boost either with that spring