I'm wondering if my vacuum is up to par with others running a ZZ4/ZZ3 cam?
I'm getting a steady 14 inches at 700 rpm idle, is that about right with this cam?

 

I've got about 16 at 600 rpm.

 

I got 14-ish ... right now I got a darn vacuum leak so the gauge wiggles between 13.5 and 14.25 (or there abouts). I think I have had my TPI apart too many times ... need new gaskets.

In diag mode (1000 RPM), it is solid at 16 or 17.


Mark.

 

I've got 16" with my LT4 HOT cam, so you should have 19 or more with a ZZ4 cam, I would think...

 

Well, I can't find any vacuum leaks of any kind, used all new gaskets the last time it was apart, the only vac line I have thats hooked up that is not ported is the PVC on the driver side, the others are either ported or capped off.
It runs darn good now that I started burning chips for it, maybe I'll experiment with the spark adv at idle as I do have a funny/odd popping sound at the tailpipe when listening thru a stethescope thats unlike any other of my cars.

 

depending also on what the inital ignition timing is set at.
but on average the zz4 had 17in of vacuum with 10° of inital.
airdeano