# vacum

**URL:** <https://forums.speedlife.net/t/vacum/112050>\
**Category:** SON240sx Automotive\
**Created:** [December 26, 2007, 2:37pm UTC](https://forums.speedlife.net/t/vacum/112050 "2007-12-26T14:37:06Z")\
**Posts on this page:** 13\
**Page:** 1

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**Author:** ![s13\_coupe](https://avatars.discourse-cdn.com/v4/letter/s/898d66/32.png) [@s13\_coupe](https://forums.speedlife.net/u/s13_coupe)\
**Post date:** [December 26, 2007, 2:37pm UTC](https://forums.speedlife.net/t/vacum/112050/1 "2007-12-26T14:37:06Z")

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im just wondering. what should the vacum be at on a stock sr?

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**Author:** ![koz](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/koz/32/5478_2.png) [@koz](https://forums.speedlife.net/u/koz)\
**Post date:** [December 26, 2007, 2:45pm UTC](https://forums.speedlife.net/t/vacum/112050/2 "2007-12-26T14:45:12Z")

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18-20

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**Author:** ![s13\_coupe](https://avatars.discourse-cdn.com/v4/letter/s/898d66/32.png) [@s13\_coupe](https://forums.speedlife.net/u/s13_coupe)\
**Post date:** [December 26, 2007, 2:54pm UTC](https://forums.speedlife.net/t/vacum/112050/3 "2007-12-26T14:54:27Z")

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and if its lower? what does that mean?

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**Author:** ![koz](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/koz/32/5478_2.png) [@koz](https://forums.speedlife.net/u/koz)\
**Post date:** [December 26, 2007, 5:02pm UTC](https://forums.speedlife.net/t/vacum/112050/4 "2007-12-26T17:02:35Z")

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you have a leak.

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**Author:** ![s13\_coupe](https://avatars.discourse-cdn.com/v4/letter/s/898d66/32.png) [@s13\_coupe](https://forums.speedlife.net/u/s13_coupe)\
**Post date:** [December 26, 2007, 5:43pm UTC](https://forums.speedlife.net/t/vacum/112050/5 "2007-12-26T17:43:57Z")

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mines at about 15 when im at idle, when im driving and my foot is off the gas its at about 18, but when i come to a complete stop it goes back down to 15

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**Author:** ![s13\_coupe](https://avatars.discourse-cdn.com/v4/letter/s/898d66/32.png) [@s13\_coupe](https://forums.speedlife.net/u/s13_coupe)\
**Post date:** [December 26, 2007, 9:06pm UTC](https://forums.speedlife.net/t/vacum/112050/6 "2007-12-26T21:06:44Z")

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is this good, bad, normal, affect power?

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**Author:** ![Theo23](https://avatars.discourse-cdn.com/v4/letter/t/43a26b/32.png) [@Theo23](https://forums.speedlife.net/u/Theo23)\
**Post date:** [December 26, 2007, 11:46pm UTC](https://forums.speedlife.net/t/vacum/112050/7 "2007-12-26T23:46:36Z")

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I don’t know what the numbers should be on an sr, but the pattern you are showing is normal.  
The engine will create more vacuum when it’s decelerating then when at idle.  
It will create less vacuum when you are hitting it ie: boost(boost, or pressure, is like the oposite of vacuum)

So yeah, something like 15psi of vacuum during idle, 18 psi vacuum while decelerating and 7 psi boost would probably be normal for a stock sr.

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**Author:** ![sil8t](https://avatars.discourse-cdn.com/v4/letter/s/ea666f/32.png) [@sil8t](https://forums.speedlife.net/u/sil8t)\
**Post date:** [December 27, 2007, 6:32am UTC](https://forums.speedlife.net/t/vacum/112050/8 "2007-12-27T06:32:58Z")

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20 at idle and decel 23 or so. running 14 psi

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**Author:** ![s13\_coupe](https://avatars.discourse-cdn.com/v4/letter/s/898d66/32.png) [@s13\_coupe](https://forums.speedlife.net/u/s13_coupe)\
**Post date:** [December 27, 2007, 8:41am UTC](https://forums.speedlife.net/t/vacum/112050/9 "2007-12-27T08:41:15Z")

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mine is exactly how theo explained

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**Author:** ![John\_sinopoli](https://avatars.discourse-cdn.com/v4/letter/j/c6cbf5/32.png) [@John\_sinopoli](https://forums.speedlife.net/u/John_sinopoli)\
**Post date:** [December 27, 2007, 10:17am UTC](https://forums.speedlife.net/t/vacum/112050/10 "2007-12-27T10:17:09Z")

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my car runs 20 inchs and idle and on decel its like around 23ish

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**Author:** ![s13\_coupe](https://avatars.discourse-cdn.com/v4/letter/s/898d66/32.png) [@s13\_coupe](https://forums.speedlife.net/u/s13_coupe)\
**Post date:** [December 27, 2007, 11:48am UTC](https://forums.speedlife.net/t/vacum/112050/11 "2007-12-27T11:48:23Z")

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so i must have a bit of a leak somewhere. thanks guys

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**Author:** ![smurf6x6](https://avatars.discourse-cdn.com/v4/letter/s/bcef8e/32.png) [@smurf6x6](https://forums.speedlife.net/u/smurf6x6)\
**Post date:** [December 28, 2007, 7:34pm UTC](https://forums.speedlife.net/t/vacum/112050/12 "2007-12-28T19:34:47Z")

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Hows the base timing?? Vacuum also changes with the base timing.

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**Author:** ![simplemind7](https://avatars.discourse-cdn.com/v4/letter/s/0ea827/32.png) [@simplemind7](https://forums.speedlife.net/u/simplemind7)\
**Post date:** [December 28, 2007, 7:46pm UTC](https://forums.speedlife.net/t/vacum/112050/13 "2007-12-28T19:46:03Z")

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could be a number of things, vacuum or boost leak test and a compression test are a good place to start.