Okay just plowed through a ton of threads before I ask this stupid question....

I've got a 11.3cr TRex cammed 408 and I am seeing steady MAPs of 67kpa at 950 idle.

It this normal?

Thanks for any response :p

 

My stocker is 30kpa.
Whats your idle speed?

That cam is pretty munchy, you might be getting reversion etc. IMHO you should have the same MAP reading as a stock displacement using the same cam maybe someone with a similar cam can chime in.

 

I see close to 55-60 with my F13. I believe a buddy of mine has a X4 and see's in the 60+ on a 346.

 

He should pull more vacume then a smaller motor with the same cam. That being said that about 10in hg of vacume, which sounds about right for that cam in a smaller motor such as a 346. I am betting that with a little more timing at idle you can get a lower KPA number and have a better idle.

 

With 27* of overlap there could be some reversion maybe. I am running 22* of timing at idle. I could play with that and see if it changes anything.

The car is like a switch...it feels pretty goofy below 2200 rpm but at about 2400rpm it just a monster till redline. Running SD, idle is good, cold start, hot start, etc... settles into a nice idle after about 5 seconds on a cold start and immediately on a hot start. IACs are 35, STITs are about .1, everything is really good. This cam just doesn't like low rpms even on a stroker. I may need to step up to 3.91s as I am running 3.46s now.

I am getting a harrop hurricane manifold here shortly so that will inevitably change the equation...