What is normal Vacum?

[speedracer]

I have a 92 with a TPIS ZZ9 cam i was checking my vacum and it shows 15 at idle causing by power brks not to work to good i added a vacum storage can and i notice a big improvement can any one tell me if 15 is normal with a alter cam?

 

[JT ZR-Won]

Speedracer, I wish I could help you out. don't know much about the vacuum on these cars. Hopefully someone will chime in who does. I'd like to check mine for a possible vacuum leak....what is the easiest way to do this?

Jay

 

[LarryBible]

I'm not familiar with that particular cam, but if it's a lot of cam, like 220degrees or more at .050, then 15 sounds about right. I would think that the brakes should work okay with that much vacuum though. Have you inspected the check valve at the brake booster?

Good luck,

 

[Chick]

One problem with putting in bigger cam shafts is less vac. A bigger cam shaft will create less vacuum at idle and light throttle conditions. You probable lost about 4 or 5 lbs of vac by doing it. Just one of the trade offs.