ZR8ED Posted September 11, 2002 Share Posted September 11, 2002 I have a boost guage on my 280 that reads in psi.. ie 18psi of boost right now. Q. I had a Greddy boost guage offered to me (reg price $229.00) still in box for $50 Prob is it reads in another format. ie .5 - 2.0 not sure the units of measurement. what is the units, and how do I convert it to psi (which I can relate to..) I want to put it on my 300zxt, as the stock guage is ****. Currently the 300zxt is boosted to approx 9-10 psi.. not sure.. that is why I need the guage... not sure how the other guage reads. if it reads .7, I would not know what that meant? Thanks, Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted September 11, 2002 Share Posted September 11, 2002 It probably reads in BAR, and 1 BAR = 14.7psi. Quote Link to comment Share on other sites More sharing options...
TimZ Posted September 12, 2002 Share Posted September 12, 2002 Well, almost. 1 atmosphere is 14.7psi, 1 bar is 14.5 psi. Don't ask me why. The other thing is that often, when gauges display in bar, they are in units of absolute pressure, instead of relative pressure. Relative pressure is the pressure difference between atmospheric pressure (~14.7psia) and the manifold pressure. This is what 'boost' is measured in. 18 psi of boost means the manifold pressure is 18psi higher than atmospheric pressure, or ~14.7 + 18 = ~32.7psia. The easy way to tell which kind you have is that absolute pressure is always positive, so if your gauge reads a positive number at idle (say ~0.5), then it is reading absolute pressure. If it is a negative number (say -0.5), then it is relative. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted September 12, 2002 Share Posted September 12, 2002 An easy way to tell if it reads absolute pressure is to check the reading with the engine off. If it is absolute pressure gauge it will read 1.0 bar or 14.7 psi. If it is reading 0 bar with the engine off, it is a differential gauge like most boost gauges. Hey - why the no show at drag day this year - I'm an OZC member who was looking for some turbo competition this year. They only other turbo car was that 280zx/GNX running in the 9's. Not quite in my league. later - Doug Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted September 14, 2002 Author Share Posted September 14, 2002 Hey all. I spent the last hour or two installing the new guage. It reads in Kg/cm Squared. I took it out for a boot, and it read approx .3-.4 Uhh .. What am I looking at? Thanks, Quote Link to comment Share on other sites More sharing options...
fl327 Posted September 14, 2002 Share Posted September 14, 2002 im too american, must read in hg or lbs or i get lost. Quote Link to comment Share on other sites More sharing options...
Doug71zt Posted September 15, 2002 Share Posted September 15, 2002 kg/cm2 is BAR or 1 kg/cm2 is pretty close to 14.5 PSI. So - .4 BAR is about 6 PSI. Sounds like either you have a leak in the line to the boost gauge, or your 300 is about at stock boost. Or your new boost gauge needs a calibration Cheers - Doug Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.