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inches of vacuum ls7

 
Old 08-04-2018, 11:58 PM
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Default inches of vacuum ls7

I have an ls7 in a 2011 z and am needing to know what the vacuum should be?
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Old 08-05-2018, 11:46 AM
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Idle? Full throttle? Which mods do you have? Kind of a stupid question without telling us ANYTHING....
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Old 08-05-2018, 03:13 PM
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At idle, hci package. And if you know anything then you should already know @ wot vac is 0
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Old 08-05-2018, 06:07 PM
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Originally Posted by PatsZ View Post
At idle, hci package. And if you know anything then you should already know @ wot vac is 0
Not if your intake system really sucks, and some do.
Which heads, which cam, and which intake? And if YOU knew anything you would have told us all this stuff in your first post.
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Old 08-05-2018, 07:37 PM
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Default G Atsma

If you know what the vacuum would be as a stock ls7 that's all I need.
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Old 08-05-2018, 08:52 PM
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When you change the heads, cam and intake as you have, the idle vacuum level changes. Stock LS7 levels no longer apply to your engine.
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Old 08-05-2018, 10:10 PM
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I'm aware of that but I need some reference numbers.
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Old 08-05-2018, 10:13 PM
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Is it currently running well? What is the vacuum level now?
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Old 08-05-2018, 10:39 PM
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No and that's why I am in need of the stock numbers. Currently it's at 4 1/2 to 5 inches.
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Old 08-05-2018, 11:09 PM
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I think you need to be looking at other factors. What is the A/F ratio? Do you have access to HPtuners or EFI Live? Which cam are you running?
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Old 08-05-2018, 11:19 PM
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The tuner that had it a while ago set the a/r a little rich to give me a window to work with I case I fix/find the problem it is 12.9. and the Cam is an fed Cam.
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Old 08-05-2018, 11:20 PM
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And no I do not have either of those programs
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Old 08-06-2018, 06:39 AM
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My 434 idles at 10 inches. Ls7 top end, with a decent sized 254/268 solid roller camshaft. Sounds like you might have a vacuum leak.
12.9 is crazy rich at idle. He set that to compensate for the leak maybe, which would lean it out badly.
MSD intake?
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Old 08-06-2018, 02:38 PM
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Thanks for your information, its not an msd intake and just recently I have checked for vacuum leaks and smoked it with no leaks found. This one is very strange.
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