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-   -   idling at 45 cmhg? is this bad? (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/idling-45-cmhg-bad-743863/)

finneymc 03-31-08 07:52 AM

idling at 45 cmhg? is this bad?
 
I read on http://www.fd3s.net/boost_test.html on the first line it says at idol you should be at 16-18hg

At idol my boost gauge says 45(ish) cmHG

I am not sure if b/c of the cmHG there is some type of conversion that needs to be done to get to HG, so that is why i am coming to the experts.

My turbos had a compression test done about 6000km ago and were both around 8-2-8.4ish (may be off by .1 or .2 i don't have the paper in front of me) so they are good.

SSSOOOooooo what do you guys think? is there a conversion that needs to be done to get from cmHG to HG or is that the same thing, if there is no conversion is it bad that i am at about 45 at idol?

thanks,
Craig

DaveW 03-31-08 08:27 AM


Originally Posted by finneymc (Post 8038560)
I read on http://www.fd3s.net/boost_test.html on the first line it says at idol you should be at 16-18hg

At idol my boost gauge says 45(ish) cmHG

I am not sure if b/c of the cmHG there is some type of conversion that needs to be done to get to HG, so that is why i am coming to the experts.

My turbos had a compression test done about 6000km ago and were both around 8-2-8.4ish (may be off by .1 or .2 i don't have the paper in front of me) so they are good.

SSSOOOooooo what do you guys think? is there a conversion that needs to be done to get from cmHG to HG or is that the same thing, if there is no conversion is it bad that i am at about 45 at idol?

thanks,
Craig

Divide the 45 by 2.54 to get inHg = ~17.7 inHg, which is very good.

GoodfellaFD3S 03-31-08 08:30 AM

2.54cm equals 1 inch, so 45 cm is 17.7 inches, your numbers are fine :). What idle rpm was this at?

Also, do you mean that you had the compression tested on your engine? Again, those are very good numbers if they're in bar.

zenofspeed 03-31-08 09:39 AM


Originally Posted by finneymc (Post 8038560)
My turbos had a compression test done about 6000km ago and were both around 8-2-8.4ish (may be off by .1 or .2 i don't have the paper in front of me) so they are good.

:scratch:

What does that mean?

DaveW 03-31-08 09:42 AM


Originally Posted by zenofspeed (Post 8038770)
:scratch:

What does that mean?

Multiply bar x 14.5 to get psi. So 8.2 bar = 120 psi, which is very good.

Rx72Heaven 03-31-08 09:48 AM

if you have a port isnt the idle lower?

Mahjik 03-31-08 10:04 AM


Originally Posted by Rx72Heaven (Post 8038794)
if you have a port isnt the idle lower?

Not necessarily the idle, but the vacuum may be lower at idle depending on the size of the port, relation to sea level, etc..

finneymc 03-31-08 05:52 PM


Originally Posted by GoodfellaFD3S (Post 8038600)
2.54cm equals 1 inch, so 45 cm is 17.7 inches, your numbers are fine :). What idle rpm was this at?

Also, do you mean that you had the compression tested on your engine? Again, those are very good numbers if they're in bar.

My idol is at about 750.

Thanks so much for this info guys i knew that I would get an educated answer here. I try to research this shit as much as i can before i post but sometimes with being out here in Japan i just can't find the answers to some of this stuff. And yes they were in bar (don't know what that means but i was told that :) )

thanks again guys, i am looking to get an american gauge very soon along with the 52mm steering colomn mount. I found that gauge mount here for like 50 bucks!

One more thing, i am about to get an aftermarket BOV, will that change my cmHG?

arghx 03-31-08 07:57 PM


Originally Posted by DaveW (Post 8038782)
Multiply bar x 14.5 to get psi. So 8.2 bar = 120 psi, which is very good.

I thought those compression tests are in K/cm^2 ? In that case, conversion is X 14.2

So 8.2 X 14.2 = 116 . Not a big difference, but bar is not exactly the same as K/cm^2 .

finneymc 03-31-08 08:04 PM

cool thanks for the knowledge!!

Rx72Heaven 03-31-08 10:23 PM

Right thats what i mean, thanks.



Originally Posted by Mahjik (Post 8038844)
Not necessarily the idle, but the vacuum may be lower at idle depending on the size of the port, relation to sea level, etc..



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