Have the LE 1.5 cam which is similar to the CC503.
Brakes are feeling a little on the soft side, I have bled them twice.

Should I be having brake problems with this size of a cam?
How do i test to see if I have adequte vacuum going to the booster, can I use a mity-vac?

 

What is the MAP reading at idle?

 

Ditto. You can pick up a vac gauge for cheap. That cam I'd imagine should give around 13-15 in/hg at a stable idle.

 

Bounces around right at 17 or so.

 

My LE3 has plenty of vacuum for brakes.

For some reason I also bled my brakes twice and thought I was going to need my vaccum canister, but after a few weeks of driving it just got better and better and eventually it feels almost like stock. Dunno why, not really scientific, but it works! Didn't end up using the canister

 

Low vacuum would give a hard pedal due to no help from the booster. Are the calipers new or what was changed? New calipers sometimes make the pedal feel softer.

 

My brakes feel a little hard to push after I've been giving the car a good run. But as for being soft I do not think that would have to do with a vacuum problem.

 

17" is plenty... your problem is not vacum

 

Nuff said.
I installed full LS1 rear brakes when I put the new motr in. I remeber befor the conversion that the front chirped a bit when the ABS kicked in, now after the rear conversion they dont chirp at all. Maybe the rears are doing more work and taking some lodoff of the front LS1 brakes. Just speculting here, but it does seem to stop good, just feels a it different.

Thanks all.

 

Actually, he said his MAP was 17 (kPa), which would be fantastic vacuum, but I doubt he meant what he said. 17" Hg is plenty.

 

My map reads ~19 (30.7-19= 11.7 incase you are wondering) on my scanmaster and I have plenty of vacuum for my brakes. The pedal is stiffer than any other stock car I have driven though, but there is still enough vacuum for brakes. If the brakes are soft its a problem with the brakes, not vacuum though.

 

I just installed a Comp vacuum canister since me new cam has been robbing vacuum. I made a bracket out of 1/8" x 1" metal stock and just brazed the pieces together. It is installed just under the ABS unit using the teo ABS bracket bolts.

It appears that this mode helped my braking noticeably.


Here are some pics for those who might be interested:


A

 

No offense, but did you mean LS1 FRONT brakes? The front brakes in a 55%-45% weight distribution car like the F-bod do up to 80% of the stopping in a max performance stop. Upgrading the rears really doesn't help, and it could hurt. I'm not sure how much different the LT1 and LS1 rear brakes are. Anyone?

With more effective rears, in a hard stop they will lock up quicker than the stock ones and go into ABS cycling. There is a good chance your stopping distance will increase, not decrease.

I do know that putting C5 front (only) brakes on an LS1 F-bod significantly improves the braking in max performance conditions and the ABS like it just fine...even with racing tires.

You might try returning to LT1 rear brakes. See if it helps. If it does, and you really want better brakes, put the LS1 back on and convert to C5 fronts. If you drive hard, you won't be sorry.

 

My cam pulls about 10" and MAP of around 65kpa and stops fine. Now with a stiffer convertor it was only pulling 8" and around 70-75KPA and would loose it holding power at red lights.

If yours was pulling 17" I'd think that would be more than enough, wonder if you booster has a leak, might want to do a vacuum test on it to see if it can hold a vacuum.

 

I have had the LS1 fronts on for years, I did just install the rears when I replced the motor a few months ago.