Intake manifold vacuum
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Joined: Oct 2007
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From: Portland Or.
Car: 1992 Z28 1LE
Engine: L98
Transmission: 700R4
Axle/Gears: SLP dana 44 3.92
Intake manifold vacuum
Roughly what kind of intake vacuum are you guys seeing with a decent size cam and heads? I am chasing an issue and wondering on vacuum. I checked my stock L98 and it's about 22in of vacuum and this 87 I'm working on has a 224/230 cam, big heads, about 10.5:1 and a big intake on it and it's around 12-13in of vacuum at idle. Is that about right for the size of cam and intake?
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Re: Intake manifold vacuum
Roughly what kind of intake vacuum are you guys seeing with a decent size cam and heads? I am chasing an issue and wondering on vacuum. I checked my stock L98 and it's about 22in of vacuum and this 87 I'm working on has a 224/230 cam, big heads, about 10.5:1 and a big intake on it and it's around 12-13in of vacuum at idle. Is that about right for the size of cam and intake?
Thread Starter
Member
iTrader: (2)
Joined: Oct 2007
Posts: 321
Likes: 18
From: Portland Or.
Car: 1992 Z28 1LE
Engine: L98
Transmission: 700R4
Axle/Gears: SLP dana 44 3.92
Re: Intake manifold vacuum
That was high idle for the stock L98, didn't think about RPM variance, I would assume it drops a little once it's warm. I will warm it up tomorrow and check, but if 13ish doesn't seem alarming then I might be ok on vacuum leaks
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