Vacuum at idle
Thread Starter
On The Tree
iTrader: (4)
Joined: Nov 2007
Posts: 114
Likes: 0
From: Northern California.
Vacuum at idle What is the standard vacuum at idle. Mine is 30Kpa or around 9 inhg. Anyone know whats normal and why some people claim 60kpa at idle? My car is almost stock.
Thread Starter
On The Tree
iTrader: (4)
Joined: Nov 2007
Posts: 114
Likes: 0
From: Northern California.
So what is normal vacuum then? I don't think I have a leak because I seem to have an increase in vacuum not a decrease. A leak puts it closer to atmospheric which is 14.7psi which is 101kpa...so anything below that is vacuum. I have heard 60kpa but mine is 30kpa... thats twice as much.
Joined: Nov 2001
Posts: 34,652
Likes: 2,578
From: Schiller Park, ILL Member: #317
18-22" is usually the norm for a stock cam in a properly tuned/proper running stock engine. 9" is far too low for a stock cam, and would suggest a cam with considerable overlap, or a vacuum leak or leak and tuning issue combined.
Even with a small cam I was able to get 14" out of an LS1 at idle. Stock should be considerably higher, but I don't recall the exact figure that I've seen before. 18-22" is a standard normal stock reading though.
Even with a small cam I was able to get 14" out of an LS1 at idle. Stock should be considerably higher, but I don't recall the exact figure that I've seen before. 18-22" is a standard normal stock reading though.
Thread Starter
On The Tree
iTrader: (4)
Joined: Nov 2007
Posts: 114
Likes: 0
From: Northern California.
That is map pressure which is a representation of vacuum because it is less then atmospheric pressure which is 101kpa. So when I turn on my car my map reads around 29-30kpa.
