Thread: What should stock SHO/FZR vacuum be?

1. What should stock SHO/FZR vacuum be?

What should stock SHO/FZR vacuum be? i've heard a couple of people say they are in the 7-9 inches Hg vacuum @ idle (all with dynotune gauges i believe) whilst I am reading almost double that with my lfg Pro-Comp (15 in HG).

Are these gauges calibrated differently? Why the difference? What kind of numbers are u guys seeing?

2. Good question Rip. Also my dynotune gauge reads .2 when the engine is off even.

3. Originally Posted by hitman
Good question Rip. Also my dynotune gauge reads .2 when the engine is off even.
Mine too...... .1 or .2 when off.
I'm getting 8.8 - 8.9 vacuum all day right now.
Dynotune gauge

4. Originally Posted by Awamori
Mine too...... .1 or .2 when off.
I'm getting 8.8 - 8.9 vacuum all day right now.
Dynotune gauge
+1

5. The digital gauge is reading in/HG and the mechanical gauge is reading -PSI.

To convert PSI to in/HG multiply by .49

6. I'm still kinda confused so those of us who are using the digital guage are seeing somewhere around 9 in/hg i guess so when you convert that we are running somewhere around 4 psi doesnt really seem right

7. Originally Posted by beerdart
The digital gauge is reading in/HG and the mechanical gauge is reading -PSI.

To convert PSI to in/HG multiply by .49
I think I have this backwards..

To convert PSI to in/hg multiply by 2.04.

So -8 PSI is 16.29

Now I am confused???

8. wow so we are actually running around 18psi at full speed.

9. That can't be right. No way we are running 18 pounds of boost.

10. Originally Posted by allstar71
wow so we are actually running around 18psi at full speed.
Originally Posted by hitman
That can't be right. No way we are running 18 pounds of boost.
I'm running at 8 lbs of boost at WOT (consistent w/ C1 wheel)and 15 in/Hg vacuum at idle........I think the differences were seeing r because the gauges r calibrated differently......dynotune must be reading metric...whatever that is..