1987 Formula - LS - Muncie 4 spd.

Front I was considering 13" C5 brakes, cross drilled, slotted with EBC pads.

Rear I purchased the 1le/LT1 backing plates from Fly N bye, so same as mentioned above.

I see a lot of people using manual boosters, but I cannot see how that would be beneficial if you plan on driving on the street ever, and as far as proportioning valve, I'd use the WilWood adjustable one.

Should I also look into an upgraded master cylinder? For that size of brakes would I have to go with a larger diameter version?

Also do the 13" rotors fit the 16" Formula rim?

 

Proper master cylinder selection is made based on pedal ratio, desired pedal effort and cross sectional area of the caliper pistons. You've got some math to do.

 

In general, 13" brakes don't fit in Formula wheels, although some may just clear.

Moving up to 17" wheels will give you the brake clearance and extra tire width you need to work well in autocross.

 

Stock master cylinder pushes enough fluid volume to operate the new brakes. No need to change the master cylinder. Larger diameter would just make the pedal harder to push and shorter travel. You wouldn't like it.

 

I will 2nd what Paul said. Larger wheels will give you better tire and brake selection. I would skip the drilled option. Most drilled rotors are not up to the heat generated by sustained competition driving and will crack. Stick with slotted or even flat face rotors. Pad choice is the most critical component of the equation. Going to larger rotors and better calipers is meaningless if you choose the wrong pad. You may go through a few variations before you find the one that works best for you but EBC is a good place to start.

As a caution: Autocross is a gateway drug to road course racing which will require you to redo your brakes again.

 

I'm going to add one more thing into what Tom said.


If you get the right brake system, you may not have to replace the entire kit for moving upstream in racing.


As an example, autocross probably won't get 1pc brake rotors hot enough to warp on 98% of cars, but road racing will. So if you get say a 13" 4 piston brake kit for autocross and move up to road racing, a pad change and moving up to 2pc rotors might be all you need to do. Get the wrong kit and you may have to replace it with something better.

 

These tools may or may not be useful.





I've haven't decided that with the upgrade to the LS front and PBR rear calipers (over whatever my stock configuration was) necessitates the need for an LS master cylinder.