FrankenMini Weblog

New Brake Calipers Ordered

The picture to the right is the brake calipers I just ordered from TCE Performance Products in nice bright red. Since my last post I've done more research and discussed things extensively with Todd over at TCE Performance Products. He punched in some numbers into various formulas and came up with some recommendations. We determined that my 1.75/1.62 Outlaw brake had way too much front bias when pared to my 1.75" 2 piston rear caliper. This will result in a very long pedal that's soft. This is what the Tilton folks said too. Considering my front calipers are leaking and in need of a rebuild I decided rather than upgrade the front master cylinder to firm up the pedal, yet still remain with a heavily front biased brake system and leaking calipers, I went with new front calipers.

Reducing the size of the front piston bore will require less fluid to push the calipers, less fluid from my smaller 0.75" master cylinder means a pedal that is more firm. I'm replacing the front calipers with the Forged Wilwood Dynalite with a 1.38*2 piston configuration. This is a significant difference over Outlaw calipers I have now. This results in the following changes.

Bias, assuming a 50:50 bias bar: 66% front for old calipers vs 56% front for the new, this allows finer grain bias adjustment, and I can ditch the proportioning valve. Which both Todd and Tilton suggested I should do.

The only draw back to moving to the smaller piston is more pedal force will be required to exert the same amount of torque on the front discs. Previously 60lbs of pressure on the brake pedal would result in 47906 inch pounds of torque on the front, I will now need 90lbs to get the same amount. Doing some reading and 90lbs on the brake seems like a good amount and what appears to be a common guideline for a non-boosted brake system. Rear torque goes from 37000 inch pounds to 24696, this is where the bias change comes in. Should be much easier to modulate the brakes with this setup.

More positive news with the Wilwood, it seems to be a smaller outside radius than the Outlaw brake. Basically this is the amount of room you need on the inside of the wheel to fit the brakes. I will reclaim approximately 2.5mm, which might not sound like much, but with this brake system is HUGE!

More to come when the brakes arrive next week sometime.

Published at 22:58:16, Friday, 29.06.07

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