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Old 07-15-2003, 12:14 PM
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Vacuum Guage Test Results.....? (Holley 600CFM))


Well, I ran home at lunch and took the mustang for a drive. I hooked up the vacuum guage and ran it with extended rubber hose through the passenger side window and took the car for a spin.

I'm sure my results are pretty standard but I am trying to decide if my engine is getting too much gas, or not enough.

The engine seems the most responsive when I feed the gas pendal in gradually ie: 1/4, then 1/2, then full throttle by the mid for some good performance.

If I punch it full throttle from a low speed, my throttle response and powerband is nowhere near as good.

At first I thought that this ment that I am getting too much gas but then I was thinking that at 1/4 and 1/2 throttle my vacuum is stronger then at full throttle when it is 0.

So, if i have vacuum secondaries then how can they be pulled in at full throttle when the vacuum is 0?

Maybe I am getting more gas at the part throttle positions because it's pulling the secondaries open with the vacuum signal, thus giving me more gas for better power?

Anyways, here are the results of the vacuum test:

"Vacuum Guage Test Rresults"

Idle in Park: 12 and Smooth
Idle in Gear: 7-8 and Smooth

Cruising: 14-16 and Smooth

1/2 Throttle: Drops down to about 6

Full Throttle: 0

Note: I have a 6.5 power valve.

What do you guys think...why do I get a crisper, stronger powercurve when I feed the gas pedal in incrementally?

Thanks, Greg.
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