Most liked posts in thread: Should a Boost Gauge show Vacuum?

I think Vacuum is a useful thing to show on the guage. Seeing how much vacuum your car pulls on a day to day basis can help to diagnose problems later down the line. Most electronic monitoring devices don't record the full readings of vacuum like a guage does either. My access port and REV for iPhone both show a max of 10-12 inches of mercury but my pro sport boost guage reads 23 inches while off the throttle coasting and 20-22 inches while at idle. Personally this is information I like to have.

 

In the USA, the vacuum should be in inches of mercury and the pressure should read in pounds per square inch.

Or in Europe, vacuum in millibars and pressure in bars.

Dave

 

This is a valid question.... Just because the gauge will "see" vacuum doesn't necessarily mean you have to display that. I get where you're coming from, Kellen.

Lots of folks have no real idea what the vacuum numbers mean... Nor interest in them. But have lots of interest in accurate boost....

 

The one I have shows vac and boost. I like it to show both.

Here is the one I have:

 

Should display both as the gauge will see both conditions. Vacuum lets you know how your engine is running also. My 2 cents.

 

SacredDisorder is correct, vacuum gauges are helpful. You can diagnose the condition of your engine. If you know the engine pulls a specific amount of vacuum at idle and things change you know you have a problem. If the needle is bouncing around you might have a burnt valve or bad rings. Then you know you need to do a compression test. You can see how the bypass valve is working, and tell the difference when you install a Detroit Tune bypass valve. You can know to look for a leak in a vacuum line if the reading goes down from normal.

 

Yes, there should be a vacuum side to the gauge.

 

Personally I like the look of Dave.O's X-Line gauge and also like the dark face that matches the JCW dark gauge faces.

 

I use the vacuum part of my boost gauge, when I'm trying for maximum miles per gallon.

If I keep the gauge in maximum vacuum for conditions, the mileage goes way up.

Dave

 

Yeeeeeah I only see vacuum when stopped.:devil::lol:

 

Vacuum shows you when the bypass valve opens. Otherwise, not as useful as boost.

I limped my car home from the track one time with a busted crank pulley - kept the car in vacuum around 45mph and it didn't throw codes or go into limp mode. But that was not a typical situation.

 

Dave, who's gauge is that. I like the face because it matches close to the JCW gauge faces.

 

I have the stock boost gauge and its half the gauge with zero at 12 o'clock. Either way the your only using 1/2 to 3/4 of both sides. You'll never hit 30" vacuum, lets hope not and never full numbered boost.

 

Vacuum info is great to have but I feel it's important to show more sweep on the boost side to better see smaller increments of boost...

 

I think it should show vacuum as well. I like seeing the gauge be a little more active.

 

Yep...