Enough Vacuum???
Enough Vacuum??? I'm Finishing up a TT home build and I am concerned with the vacuum numbers I'm getting. Keep in mind this hasn't seen the tuner yet and the idle is rough if barely there. But with a little pedal work I can hold an idle and I'm only seeing 10-11 in/hg @ 900 rpm. I've checked for leaks. Ran 10psi into the manifold with air compressor and no leaks from the back (or anywhere else). All air lines have been checked as well with no leaks. I'm running 317 heads and a custom grind TT cam. Thoughts?? I'm running AEM Tru boost but also checked with analog vacuum gauge run straight to manifold outlet to verify and they match.
I think you need to get the thing to idle, anytime your on the gas the blades may be open just slightly allowing more air in and showing a low reading, your gauge does read in/hg correct, I was worried on mine initially as I was only seeing 7, but found out its reading in -lbs vs in/hg. Also I had a ported TB which caused me a mess of problems and ended up switching back to a stock TB.
When I first fired up my 02 after putting on the front mount with bigger injectors I had about 6-7 in at idle and it was ROUGH. After my tuner sent me a base tune and I adjusted the throttle blades I have 12-13 in and it idles great at 800 rpm. Get it tuned and then worry about the idle vacuum. Cheers.
