Im Curious Whats Your Vacume?on Idle

[cosworth1971]

just curious! on your boost guage what does it vacume at on idle?mine is around 18-20 psi ,which would say quiet good no?and also 18-20 wud mean no leaks at all?In old motors 18 vacume was good.

If your is different please post it

p.s i think my cheapo boost gauge says 13 psi when it is actually around 11?

if you have wrong reading with guages please post back also

[siddr20]

wow hold up.. 18-20psi on idle??

or am i reading your post totally wrong..

Mine is like negative 0.7 bar.. at idle.. that means its not on boost..

Edited July 28, 2007 by siddr20

[silver gts-t]

wow hold up.. 18-20psi on idle??

or am i reading your post totally wrong..

Mine is like negative 0.7 bar.. at idle.. that means its not on boost..

i think he's saying 18-20 in vacuum

[cosworth1971]

wow hold up.. 18-20psi on idle??

or am i reading your post totally wrong..

Mine is like negative 0.7 bar.. at idle.. that means its not on boost..

.7 bar is about 10 psi but that guage isnt very accurate if its the standard one?and 10 psi is weak i think?

and yes i mean 18 to 20 psi vacume at idle

Edited July 28, 2007 by cosworth1971

[Rolls]

Its actually mmHG not psi when you are talking about the negative units on your boost guage. You can't really have negative pounds per square inch if you think about it.

But yeah mine sits on ~ -20 on idle.

Edited July 28, 2007 by Rolls

[RB30-POWER]

with standard cams and no vac leaks with engine warm it should be around 20" vac.

bigger cams and you will have less vac.

[mad082]

mine used to sit at about 20 vacuum at idle, and on decel it would go to about 25.

[WogsRus]

well i have tested mine so much i cna't find any leaks at all anywhere, and mine still only sits at 18" mercury at idle at 650 rpm and about 19-20 at 750 rpm.

Any common leaks to look out for, did a whole heap of test break clener, carb cleaner, smoke, pressure, all good.

[RB30-POWER]

is your guage accurate?

you would get maybe 18" on idle with electrical loads and a/c turned on. (more air entering through idle bypass solenoid to maintain idle rpm with loads on engine = less vac)

[WogsRus]

as far as i can tell, it roughly corelates with the stock boost guage.

[PM-R33]

Mine sits on about -0.6 bar on my stock gauge and on my aftermarket one which is around -10psi

How the hell are uz gettting -18psi?? The stock gauge only goes to -1 bar which is -14psi??

[RBwhatever]

Its actually mmHG not psi when you are talking about the negative units on your boost guage. You can't really have negative pounds per square inch if you think about it.

But yeah mine sits on ~ -20 on idle.

Should be IN-HG not mmHG. Well, it is on mine anyway.

[RBwhatever]

Mine sits on about -0.6 bar on my stock gauge and on my aftermarket one which is around -10psi

How the hell are uz gettting -18psi?? The stock gauge only goes to -1 bar which is -14psi??

They mean 18 IN-HG not PSI.

[SilverECR33]

mine sits at 18-20, i think it merely shows the innaccuracy of the aftermarket boost gauge... either that or a slight intake leak. will know for sure in a few weeks

[Green_s13]

you should have 20" at idle mine had 18.5 and i have no air leaks turned out to be the inlet cam was out by two teeth.

[cosworth1971]

I wonder if its still = to a PSI because its on the same scale.18 to 20 seems good but to those who get 10 psi ,i would question there reading?

[PM-R33]

They mean 18 IN-HG not PSI.

Oh ok cheers! I was gonna fu**ing say, how the hell people were getting -18psi!!! Both mine and my mates sit on about -0.6, -0.7 bar.

[cosworth1971]

Oh ok cheers! I was gonna fu**ing say, how the hell people were getting -18psi!!! Both mine and my mates sit on about -0.6, -0.7 bar.

but u earlier posted and said ur aftermarket said -10(in-hg)psi (whateva)

and tha factory boost guage is just there to look pretty IMO and wont give u a good reading

[PM-R33]

but u earlier posted and said ur aftermarket said -10(in-hg)psi (whateva)

and tha factory boost guage is just there to look pretty IMO and wont give u a good reading

Yeah aftermarket says -10psi, stock one reads about -0.7 bar which is equal to -9.8psi

Nowhere near -18psi.

[cosworth1971]

Yeah aftermarket says -10psi, stock one reads about -0.7 bar which is equal to -9.8psi

Nowhere near -18psi.

airleaking then ?whats ur friends say on aftermarket? cause thats quiet a differance?