Post your vacuum at an idle

[2bav8]

Got a kick out of everyone's idle RPMs.
Just curious what vacuum everyone is pulling.

I manage 7" at 900 RPM

 

[mustang70]

Ummm.....I think it was around 18" last time I checked.

 

[INDSKYS]

18 To 22

 

[hungrymonkey]

before the motor blew in my truck. it was 16-17 mmhg.

 

[crushnut]

19 to 20

 

[10secgoal]

10-11in.

 

[2nd Mustang]

12 at 1000 rpm idle.

 

[Ozsum67]

20" and a rock steady needle at 4200' in elevation, which translates to 24"+ at sea level.

 

[pabear89]

15 in at idle

 

[blown65]

9" at 1500 rpm idle.

 

[69 302/351c]

18 " at idle on both cars at about 800 rpm.

 

[my66coupe]

15 at idle, on my old engine. A engine will make worse vacumm with a larger cam correct? This makes it difficult to tune, I assume.

Mike

 

[crushnut]

15 at idle, on my old engine. A engine will make worse vacumm with a larger cam correct? This makes it difficult to tune, I assume.

Mike

Correct

 

[my66coupe]

Sorry to go off topic for a bit, but when you set your timing, it is correct to set it to where you get the largest amount of vacumm at a idle?

Mike

 

[Lswhat]

20

 

[wickedmach1]

What is a safe number for vacuum if you are using power disc brakes on front and drums on rear for my 70 Mustang? Don't care to use a vacuum pump?

 

[12sec67]

18 at 1000 rpms

 

[67GTA-FB429]

just played with mine today....

12 at idle, and lumpy (see cam specs)

 

[2nd Mustang]

What is a safe number for vacuum if you are using power disc brakes on front and drums on rear for my 70 Mustang? Don't care to use a vacuum pump?

I have a mild hyd roller cam and with 12 in. of vacuum, my power front discs and rear drums work just fine. Actually those darn Kelsey-Hayes 4 piston calipers on front are really grabby, even with only 12 in. of vacuum. I think I read somewhere that less than 12 in. would be a problem on power brakes, but not sure of the minimum vacuum needed.

 

[ashford]

16 on 289 in falcon
8 on 302 in capri