15in hg at idle normal??

[acannell]

Ive seen it posted that factory spec on the 2.2/2.5 allows vac to be as bad as 15 in Hg at idle?? Just wondering if this is true and how this makes sense? The lowest idle vac on my 2.5 I've ever seen is maybe 20Hg and thats with 150k miles...after a crappy rebuild I always get 22hg. 18Hg means a piston is cracked guaranteed.

[Force Fed Mopar]

The 2.2's have a bit less, IIRC my rebuilt 2.2 had about 18' at idle w/ a FM 475 cam. The 2.5 in my Lebaron idles at 20", stock cam.

[acannell]

ahh that makes sense

[Gaboon]

My 2.2 with perfect compression has 14 Hg at idle but I have an agressive roller cam installed.
That said, cam choice and installed centerline will have an effect on vac.

[iTurbo]

I usually see 14-15 in/hg vacuum on my 2.2/2.5 cars at idle and they are relatively stock with exhaust and intake mods. I chalk it up to living at ~4500 ft.

In Laramie WY (7200 ft) it is more like 10-12 in/hg.

[thedon809]

My old 2.2 engine with a pitted #1 cyl wall would still pull 17-18inhg. It burned oil like hell though.

[tryingbe]

My old 2.2 engine with a pitted #1 cyl wall would still pull 17-18inhg. It burned oil like hell though.

Same with this cylinder wall.

[GLHNSLHT2]

elevation plays a huge roll on vacuum. I'm at 2000ish feet and when I'd go to portland (under 1000ft) I get 3 extra inches of vac.

[wheming]

About 16 "Hg is normal for me with a 2.5 using the TU R5 cam.