hi, i have a question, at idle (1200 for me) i have 400-500mmhg. this should be about 7.73464psi-9.6683psi of vaccum. i know this is very off from the normal 16-20 psi people talk about getting at idle and was wondering what this could be. is my boost gauge broken? i think my engine is ported and im running a cia as well as a smic intercooler and a straight pipe with a 1.25" restrictor plate (the restrictor plate did not really do anything to the idle). the car seems to run well. it idles nicely as well as accelerates smoothly to redline and handles like a dream. anyone have any ideas?

oh yeah, i forgot to mention that 16psi=827.4464mmhg and 20psi=1034.308 yet my boost gauge max vaccum setting is at 750mmhg which is only 14.5psi which is not even close to the 16-20psi your soppose to get with a rx7.

am i reading this all wrong? btw its a greddy boost gauge, not sure on what series it is.

 

You are getting your conversions confused. Your vacuum registers in English inHg. To convert mmHg you divide the number of mmHg by 25.4. Example: if you are seeing 400mmHg of vacuum at 800rpm, then your vacuum reading at idle in InHg is 15.75inHg. Got it? I have a greddy boost gauge also and once you know the set up and what is normal you can index your readings better. As far as your boost gauge is concerned, it probably reads boost in Kg/cm2. The conversion for this is 14.22psi per 1Kg/cm2. Example is .5kg/cm2 reading on boost gauge=7.1psi. Got it now?
Art

 

Go to this site:

http://vaibhavweb.tripod.com/index.htm#downloads

and download metric converter. It will save you a lot of headaches. I will do all your conversions for you.

 

ahhh i c now,. thanks you