A friend of mine told me that instead of having a blow off Valve, have no boost release Says it makes a turbo faster. not sure what to think . anyone ever hear about this ? is it dangerous ?and pros and cons on the whole Idea?
there are some japanese BOV's designed to run that sort of boost.
Failing that, make your own. they aren't exactly complex things - we have had our own made up before, and there is no reason you couldn't make something that would be strong enough to handle those sorts of pressures.....
The notion that you cant make seals hold more than 35psi is simply rediculous - if your whole inlet system can hold 35psi then so can your BOV.
Get something like a HKS type R Bov or trust type R - whoever it is that makes the bigass racing ones.. they are exxy - but they will hold that pressure fine...
I think that the HKS Racing II is rated up to 40psi, and that under normal circumstances would be fine. But I think we're going to need something with some "clamping" power. With those kinds of pressures, I'd think that once it's open, say between gear shifts, it's be hard to get it closed again. I had a similar problem this time last year with my Greddy Type R.
I guess it'll take some experimentation. I've been talking to diesel truck guys running 800HP in their dodge pickups, and finding out what they use. It's all a mystery when you start pumping up the boost pressure, and a lot of guys don't want to give away the farm as far as the experiences they've had and what they've learned.
interesting, i didnt even know it was an issue having the valve close between shifts. what do the drag cars use? like the twin y2k v8's? do they use the wastegate idea? hmm, i guess this isnt as simple as the double blowoff valve problem like a HKS racing 2 followed by a SSQV.
I was reading about Bob Norwoods MR2 that he used to blast through records at teh salt flats, and he brought up some good points. Through trial and error, they found that, because of the boost pressure, the valves in the cylinder head had a harder time seating. I'm not sure what sort of springs they ran, but they reiniforced it immediately. My head is being ported more extensively than before and we're installing springs that can handle insane boost pressures like that. It seems that SO many things that you take for granted, like the BOV clamping shut after the shift, are out the window. I was thinking of popping open my Greddy BOV to take a look inside and see if we couldn't fabricate something where we could put a spring within a spring, but I haven't been around to do it. A dual spring set-up would definitely have some clamping power.