quote:Originally posted by George P:quote:Originally posted by PanteraDoug:
... 1 inch of vacuum is approximately 1 psi of negative pressure ...
Not even close. 1"Hg = 0.49 psig
What's a psig?
If you say so. I know that with the supercharger 1 atmosphere is the weight of the atmosphere at sea level. That's taken as a standard 14psi.
Ooo, now you made me forget how many inches of vacuum that is?
If you look at the supercharger gauges, some are marked in atmospheres and psi.
3 atmospheres is around 35-37 psi in reality. That I saw running in a SB Chebbie and I couldn't get the conversion numbers right? We couldn't figure out what it would take to blow out the head gaskets...but I digress.
As I said, I look at it in inches of vacuum since that's how my gauges are marked on the vacuum side but once they go to boost they are marked in psi.
I'll get out a caliper and measure the increments of both and make a conversion factor and tatoo it on my far head...wait, I won't be able to see that? Scratch that idea.
12 inches is about all the seals like the crankshaft can take without getting sucked in so the thought is for a safety factor 10 inches is a good number to aim for?
Venting the crankcase through the headers only yields around 4 inches of vacuum and that is at high rpm basically.
Every engine needs crankcase vacuum to seal the rings or maybe more correctly make them work right.
So I'm off "just a little" on my conversions? So shoot me? Just don't tell Marlin. He'll be sending me dirty emails.
