Wierd issue with boost gauges.

[Jiggalude]

So I've been having an "issue" with my car only having 14-16 lb/hg at idle. So I have another boost gauge and I decided to see if that was the issue, and that gauge read 20 lb/hg! The strange thing is, when I went out and took it for a test drive, they both read around 9 or 10 psi. Now how can one read more vacuum, but they both read the same amount of psi? The gauge that was reading 14-16 is an autometer gauge out of an SRT 4, and the hole in the nipple that goes to the boost source is a bit bigger than the other gauge. Could that have something to do with how it reads?

 

[ramsack]

the nipple size i don't think would have anything to do with it because you would see different boost readings as well. mechanical gauges are good for speed, but IMO they become inaccurate pretty quick when you need to read a small force like boost or vacuum. the copper tubing inside that flexes gets fatigued pretty easy.

 

[Jiggalude]

Hmmm, but I don't understand why they would read the same PSI but different vacuum. The one that reads more vacuum i think is a glow shift gauge, where as the other one is out of an SRT 4 which is autometer. Are you suggesting I get an electronic boost gauge?