S-trim help: is a bypass valve upgrade necessary beyond 12psi?

I modified your post's title. Hopefully it will help you get a response from someone in the know.

I know you're looking for personal experience, and I don't have any. However, I would personally go with vortech's recommendation. You can probably get away with not having a bigger blow-off, but the pressures exerted when going from full boost to throttle plate closed can put a lot of strain on the compressor. I'm sure they're strong enough to stand up to the added stress for a while... maybe even a long time, but the increased wear could potentially cause fatigue issues that would not have happened with a correctly sized blow-off. Nobody knows the equipment better than the manufacturer.

Still, I'm not that familiar with the blower in question, and I hope someone on here can help you.

Chris

The stock plastic Bosch valve will work fine with 12psi with the S-trim. Chris is right though a larger bypass valve will ensure that no air is trying to push back against the blower. Just be prepared for more belt slippage when you go 2.95, the Vortech tensioner system is not that great IMO. Resist the urge to crank down on the belt, it causes major issues with the front crank bearings and stress on the snout.

To swap to a larger valve you will need to upgrade your pipes....



Chris/Fastdriver, how's the car??? I forgot to tell you they screwed up and actually sent me a GT42 76mm, ball bearing!!!

u

Rick,good to see ya.

Man I haven't touched the car in so long. But I should be done with the career course I'm in next friday.

No change in my future plans. You should see the car when I get back from ranger school.

Chris

Oh and nice catch on the turbo. Huge difference in value. I paid over 2k for mine. That will definitely help with spool by several hundred rpm.

I'm not sure where the valve is mounted, but I assume that what Rick meant is that the upgraded valve will be too big to fit on the stock pipe, or that the pipe that leads from the valve back to the intake tract will have to increase in size along with the valve.