Vacuum Reading

[Gerry M]

Whats sort of vacuum should a boost gauge read at idle. I\'m trying to figure out how healthy my engine is.

[grinder]

from speaking to then next door neighbour last night - he says that his reads about -0.7bar

dont quote me as i dont know for sure

but my TII sits at about that at idle

thanks

stu

[fro]

I get -15psi on mine at idle. that\'s just a little bit over over -1 bar

[20B_boy]

Eh? vaccum wont be measured in bar or psi??

[grinder]

errr mine does on a boost gauge / confused now /

[Gerry M]

my gauge reads in cmhg (cm in mercury) on the negative side. found this on the net.

Normal stock motor will show 18" or better.
Mildly ported motors show 14"-16".
Heavily ported motors can go down to 10"-12".

that converted to cm hg works out at

Normal 45.72
Mild 35.5 - 40.6
Heavy 25.4 - 30.4


Mine reads higher than the normal (48cmhg), could this indicate that its already been rebuilt??

[fro]

Originally posted by 20B_boy
Eh? vaccum wont be measured in bar or psi??

Doh, yeah the vacuum on my gauge is in inches of mercury.. the units are written in the smallest writing in the world. So that\'s 15" or 38.1cm
I need a holiday :rolleyes:

[Gerry M]

To Convert from... BARS (bar)  

To...       Multiply By
InHg      29.5300
ftH20     0.0833333
kgf /cm  2 1.01972
inHg      0.0735559
lbf/in2   14.5038

[Gerry M]

//www.onlineconversion.com is handy!

[sadgoth]

Saw the title Vacuum Reading, and I thought about time someone decided to clean my home town! :rollin :rollin :rollin

Sorry, couldn\'t resist!, I\'ll get me coat.....

[grinder]

dont worry matey - i\'ll get your coat for you