My MAP on the scanmaster reads 17.5 "HG.

I hooked my mity-vac up to the intake fitting that goes to the brake booster, it read 12" HG.

Will this affect A/F or brakes?
Do I have a problem here?
Thanks

 

GMs are a little wierd here, that 17.5 gets subtracted from the BARO reading, usually 28-30, so, 29-17.5=11.5, so, you have low vacuum



you might have OK brakes

 

Nothing "wierd" about GM.... its basic physics. MAP is by definition the pressure in the intake manifold referenced to absolute pressure (0 psi/0 "Hg/0 kPa)). Vacuum is the pressure in the manifold referenced to atmospheric pressure (approx 14.7 psi/29.92 "Hg/101.5 kPa at sea level).

To understand the MAP reading on your ScanMaster and how to convert it to vacuum, read this:

http://members.aol.com/InjuneerZZ/ScanMast.htm

 

The brakes are what I am concerned with, they feel different from the stock motor so it must be related.

Anybody have any solid facts that this 12" HG is inadequate for full LS1 brakes?

 

My cam's probably around the same size as yours and I'm running C5 brakes up front. The pedal is stiffer than cars with a stock cam, but they still work fine you just have to push a little harder. I actually like the stiffer pedal.

 

I really don't like the hard pedal feel of the brakes right now, might like to add a vacuum canister.

Does anyone have opinions on this?
Any other ideas?