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What is an average vacuum reading?

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Old 07-07-2003, 12:34 AM
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badass951
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Post What is an average vacuum reading?
I think I fixed my vacuum leak, and my gauage now reads like 16 in. per HG at idle. I spoke with a few other people and they said this was a good level, but I just want to double check.
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Old 07-07-2003, 12:49 AM
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smkn951
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i had a similar question before.
do a search on"negative on boost"
danno, explained it clearly on this thread.
goodluck
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Old 07-07-2003, 01:20 AM
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badass951
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I see that, but that does not tell me what it should read at idle. What does your gauge read at idle?
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Old 07-07-2003, 01:37 AM
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ian
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Mine seems to come in 15 inches at idle, and I have been over the car 100 times trying to find any other leak...
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Old 07-07-2003, 01:38 AM
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Danno
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Good vacuum with a well sealed engine is around 15-22 in.HG (depends upon exact idle-RPM also). If you've got less than 12 in.HG, the engine's getting worn and isn't sealing as well anymore.
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Old 07-07-2003, 08:09 AM
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tjbreen
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I get 18 inches HG on my VDO meter at idle (950 rpm). It jumps to 22+ when engine braking. I guess I can stop replacing vacuum line connectors.
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Old 07-07-2003, 09:06 AM
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awilson40
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I get about 14-15 on a cold engine.
18 at idle when warm. 22 on engine braking also.
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Old 07-07-2003, 09:06 AM
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awilson40
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I get about 14-15 on a cold engine.
18 at idle when warm. 22 on engine braking also.
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Old 07-07-2003, 09:56 AM
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Jake951
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17-18 inches here on a warm engine.
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Old 07-07-2003, 11:50 AM
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smkn951
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14-16 here, i guess it's safe to say that my car is running well?
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Old 07-07-2003, 08:16 PM
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Luke
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18-19 on warm and this was before I discovered I had completely smoked valve guides. How is that possibly?
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Old 07-07-2003, 10:20 PM
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SamGrant951
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18 at idle here, but im loosing coolant somewhere, and it aint on the damn ground...eek!
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Old 07-07-2003, 10:59 PM
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20 at idle...

hey sam sounds like a new headgasket is in order.How much coolant are you loosing a week? i was just curious cause i have the same problem and i want to know how long i have until i have to change the headgasket myself.....especially since i am pushing 16 psi!!
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Old 07-08-2003, 12:13 AM
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TonyG
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From what I've seen, 17"-19" is what you get with a 951 with a stock cam, engine and tuning in proper condition.

With a big cam, the vacuum should be at about 11"-12", and the engine in good condition tuned properly.

15" is too low on a stock cam 951 engine.
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Old 07-08-2003, 12:45 AM
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ian kam
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what does everyones vacum read when the A/C is turned on...mine goes to about 12?? when off a good 16-18
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