What is everyone's vacuum at cruise?

[ILikeCarsYesIDo]

Say you're cruising 75 MPH down the highway with cruise control on, what's your vacuum reading?

A few days ago mine was reading -10 PSI and now it's reading at about -19 PSI. Vacuum at idle is normal, at -21 PSI. Once there is daylight, I will check all of the vacuum lines, but this got me curious as to what everyone else's vacuum readings at cruise were.

 

[A-to-the-J]

Say you're cruising 75 MPH down the highway with cruise control on, what's your vacuum reading?

A few days ago mine was reading -10 PSI and now it's reading at about -19 PSI. Vacuum at idle is normal, at -21 PSI. Once there is daylight, I will check all of the vacuum lines, but this got me curious as to what everyone else's vacuum readings at cruise were.

doesen't it depend on how open the throttle is?

 

[Mischief7m]

well, first off, vacuum is not read in psi or -psi, its in in/hg or inches of mercury. and on a flat road not accelerating at about 75 i believe about 10-15 in/hg is normal

 

[Doward]

Yeah, the PSI was bugging me, too

~13-16 more or less @ 70mph cruise on flat ground.

 

[ILikeCarsYesIDo]

You guys meant what I knew! Inches of mercury schmercury.

 

[grimreaper]

dang lots of variables, seen it go almost to -2 and as low as -26.

 

[suprabad]

12-14

 

[jpeek29208]

10-15

 

[mkiii222]

50 to 60 kPa / 15 to 18 in/hg average cruise
65-66 kPa / 19-20 in/hg idle
70-85 kPa / 21-25 in/hg decel (25 at ~3.5k rpm)