2G vacuum readings higher when rev

[mnypit]

Hey guys! Just did some work on my gsx which included installing a boost gauge. It reads 12psi of vacuum at idle, but when i rev to 3k the vacuum goes up to 20. Getting in a couple parts in soon to run a boost leak test. Do you guys think I have a leak or different problem?

Thanks!

 

[pauleyman]

Update your profile please. What mods are on the car? Vacuum shouldn't read psi. Mmhg?

 

[mnypit]

sorry just updated my profile. Listed the mods that are on the car. Just put the s90 TB on and had the exhaust manifold off to replace a broken manifold bolt. Decided to install a boost gauge to read boost so i didnt have to look at ECMlink on a computer to see what its at. starts at around -12 at idle and goes up to -20 at 2800-3000 rpms.

 

[DSMPT]

Your gauge is probably reading in in-hg. If so and if 12"hg at idle and 20"hg at 3000 rpm in neutral, it sounds normal to me. Cam spec, valve timing etc would affect that though.

 

[BLACK'98DSM]

Is it at that number when you let off? When you rev the engine and suddenly let off the throttle, it will make stronger vacuum as it idles back down.