Tiny little honkin brakes

[nomadtrash]

I am working on the next phase of my racecar project. This is the brake phase. It will serve two purposes. First it will remove unsprung weight and total vehicle weight. Secondly it will increase braking capacity. Thirdly it will give more wheel clearance. Autocross does not require tremendous braking capacity. Over the course of 60 seconds there may be three 60-20mph hard braking areas. The desired performance is a system that requires no warmup, has good initial bite, and has no fade.

I am currently running modified stock front brake calipers and a 280Z 7/8" master cylinder. The calipers and front rotors have been modified to fit inside my 13" wheels. The stock calipers are around 10 pounds each and have two 2-1/8" pistons. The pad availability and selection is poor for autocross racing performance reqirements.

I want to replace the calipers with light weight aluminum ones. The two candidates I have narrowed my search to are the Outlaw 1000 and the Wilwood Dynalite.

The Outlaw 1000 contains two 1-3/4" pistons and weighs 1-1/2 pounds. I think the braking capacity will be acceptable but the pedal effort will be too high.

The Wilwood contains four pistons and different piston size options and weigh 3 pounds. The 1-1/2" piston option gives identical piston area as the 2-1/8" roadster brakes. The pedal effort will be the same as the current setup.

My questions are:

1. What size master cylinder would work well with the Outlaw 1000? It would have to be smaller than the OEM 5/8" Roadster unit. I would like to keep the stock mounting location and bolt spacing. Did a 510, 411, 310, 210, etc... come with a smaller diameter MC that will fit? I can deal with metric vs standard fittings so it isn't an issue.

2. Will the smaller diameter two piston caliper perform as well as the larger four piston one? Both will have similar swept area but the two piston one has less pad area. It seems that the smaller pads will heat up faster and provide maximum perofrmance earlier than the larger pads.

I will be making custom brackets to hang the calipers. Will hanging them near the lower ball joint help any? It will lower the center of gravity. Is there a reason that most calipers are hung at the top of the rotor?

I'm leaning towards the Outlaw 1000 because it is lighter and costs less. I just need some solid reasoning from the peanut gallery to support or discredit my choice.

Thanks,

[garth]

As stated in previous posts regarding brakes, “whether repairing, modifying or selecting a brake for new application, one should be extremely cautious and respect their limits�.

My opinion, for it what is worth considering I'm sitting in the peanut gallery.

1) If you select the Outlaw 1000 calipers I think the system would perform closer to your expectations with a MC size of 7/8�. A smaller 5/8� MC would require almost 2.5 times the brake pedal force to match original braking power. The smaller MC would have greater delay and be more prone to fade.

Based on the information provided, I would select the four 1.5� piston calipers coupled to a 7/8� MC.

2) I agree with your assertion that the smaller pad area would heat faster and achieve maximum performance sooner. The downside would be increased pad replacement frequency.

I think caliper placement is primarily a function of the spacing of the entire spindle/suspension assembly.

Good, quick, safe, stops to you!

Let us know your choice and the system's performance.

[Dave]

Yes! Please keep us informed. And please take good notes of your bracket design. Some of us may be interested in following in your footsteps....