sunshine

iTrader: (3)

I saw that Autometer makes a Vacc/Boost gauge, and just a Boost gauge.
What are the differences between them? What does the vacc side show you?

Which is more desirable on a turbo car?
Can one of these gauges be used for any purpose on an N/A car?

Thanks,
-a

Please restrain from immature responses regarding: a) autometer quality, and b) the reason fr putting a vacc/boost gauge on an N/A.
Thanks

drewl

NA cars will read just above -14.7 psi with the throttle closed, and 0 psi at WOT. since there's no turbo raising the pressure, it will never read above 0 psi.

a turbo car will read just above -14.7 psi with the throttle closed, and whatever it's boosting at WOT.

being able to see vac is helpful for knowing if there's a vacuum leak. also nice to know it if you have your safc reading pressure instead of throttle

HeffBoost

I'm not a fan of autometer's stuff, check out VDO.

I opted for a boost only gauge (vdo) and in hindsight I wish I had gotten the vac/boost unit. It would be nice to have an accurate vac reading too.

sunshine

iTrader: (3)

How would you wire a vacc/boost gauge on an N/A? Tap into the pressure sensor tube?
-a

drewl

any vacuum hose on the intake manifold after the throttle body should be okay

NZConvertible

One shows boost and vacuum, the other shows just vacuum. Seems obvious...

Post-throttle manifold vacuum.

Desire has nothing to do with it. If you mean which is more useful, then the one that can read both will always be more useful.

A vac/boost gauge would be half useless; a boost-only gauge would be completely useless. You use a vacuum gauge on NA engines.

slpin

iTrader: (9)

uhhh... no
it will read more than 14.7 at idle...
14.7 has nothing to do with it

NZConvertible

Actually 14.7psi is atmospheric pressure, so it does have something to do with it. But he's still wrong.

With the throttle closed, manifold vacuum will vary according to engine rpm. It'll be 14-18inHg (7-9psi) at idle and 20-22inHg (10-11psi) at higher revs (i.e. decel).