Vacuum Pressure Issue?

[GotTurbo?]

Ok, I think I need some info...I've searched all the threads...but can't find an answer...
I understand that if we have a leak in our vacuum lines...our boost gauge will be between 20in hg and 0 (usually).
So here goes....For the past 2 months my boost gauge was reading fine 6.9psi boost and 20in hg vacuum and 0 at idle.
Today--still 6.9psi boost...but after i let the gas go. the needle drops down to 23-25in hg vacuum. How did i get more vacuum pressure all of a sudden?
Same temp outside...same elevation...that wouldn't matter anyway would it.
Just asking is this normal or is something wrong
Any info will be greatly appreciated. Thanks in advance

[KyRaceFan]

Mine drops to 25 or so when im still rolling and have the clutch in, while stopping.

[dominoy2k1]

good question, i noticed same readings but never thought anything about it...

[GotTurbo?]

Mine drops to 25 or so when im still rolling and have the clutch in, while stopping.
Thanks man..that makes me feel better that it does go down to 25.
But is it normal that it has always been at 20in hg for over 2months, and today it suddenly dropped down to 25in hg?

[MSP FOR LIFE]

no clue i usually drop to 21 22 sometimes prolly close to 25

[GotTurbo?]

more vacuum pressure????? maybe there's a kink in my vacuum line? could that be it??? but i don't see any? seriously wtf?

[KyRaceFan]

vacuum leak=less vacuum pressure, not more(higher)
Is your car pulling that much vacuum at idle or under clutch-in decelleration?
Mine reads perfect 22 at idle with no fans on, such as a/c, heat.
Under clutch in braking, it reads as low as 25.

[GotTurbo?]

vacuum leak=less vacuum pressure, not more(higher)
Is your car pulling that much vacuum at idle or under clutch-in decelleration?
Mine reads perfect 22 at idle with no fans on, such as a/c, heat.
Under clutch in braking, it reads as low as 25.
i'm sorry, i didn't clarify before. i understand that vacuum leak=less pressure
but thing i'm concerned about is the sudden change today...for 2months it's always been steady but today it increased to 25in hg...
i'm just concerned about the change..
thanks for the info though

[KyRaceFan]

I wouldnt worry about it.
Does the car feel the same, spool up the same?

[GotTurbo?]

I wouldnt worry about it.
Does the car feel the same, spool up the same?

yeah, i believe so...sorry bout the questions, just nervous bout it. thanks for the peace of mind though...from all the threads that i've seen you reply on i trust your judgement. thanks for the peace of mind

[Dr.Sound]

every car reads differently
on my first MSP it read 25-23 vac at idle
on the current one 21-19 vac.....no leaks or kinks

just depends on the car

[CatD399]

I assume your vaccuum gauges are installed before your turbo? If so the extra vaccuum you are getting is simply an indication of your air filters being dirty....
The boost pressure will remain the same because it is controlled by your wastegate/bpv/bov/whatever, but in theory your turbos will be spinning higher...

[GotTurbo?]

I assume your vaccuum gauges are installed before your turbo? If so the extra vaccuum you are getting is simply an indication of your air filters being dirty....
The boost pressure will remain the same because it is controlled by your wastegate/bpv/bov/whatever, but in theory your turbos will be spinning higher...
good point..never thought of that...filter just being dirty...thanks for the info

[KyRaceFan]

I assume your vaccuum gauges are installed before your turbo? If so the extra vaccuum you are getting is simply an indication of your air filters being dirty....
The boost pressure will remain the same because it is controlled by your wastegate/bpv/bov/whatever, but in theory your turbos will be spinning higher...


A dirty filter likely wouldnt cause a jump in just one day, but it could be something to check on.
Boost pressure is controlled by the wastegate, and vacuum change wouldnt cause your turbo to spin higher.