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Old 07-09-2018, 06:42 PM   #489
6130
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Join Date: Jul 2012
Location: Texas
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Default Re: H-I-J '76 Nova re-fit.

Todd, I don't know whether you plan for her to run H, I, or J Stock, but I guess one consideration would be how often you think your daughter would be likely to come up against a stick car in her class. It looks like you've done a lot of high-quality work there- I see no reason the car shouldn't run under index. And if heads-up races are unlikely, then the rear brakes may not matter from a performance perspective.

From a safety perspective, disc brakes would be better. Especially when racing with breakout rules.

Most automotive drum brakes are self-energizing, so the actual braking force is progressive, rather than linear. A light push on the pedal would result in almost no braking force in the rear, a moderate push on the brake pedal would result in moderate braking force in the rear, and a hard push on the brake pedal may result in rear brake lockup. I'm sure we've all driven a car from the '60s with power 4-wheel drum brakes- you know this feeling, where light pedal pressure does nothing, moderate brake pedal pressure gives you the braking force that you're aiming for, and heavy brake pedal pressure locks up the wheels unexpectedly.

This is compounded with the vehicle's weight transfer under braking- the harder the driver brakes, the more weight is transferred to the front- and yet the rear brake forces ramp up disproportionate to the actual brake pedal pressure, while the front brakes are responding in a linear fashion.

Disc brakes are much less likely to lock up, because they are much more linear- the actual braking force is directly proportional to the brake pedal pressure. This makes it much easier to modulate the brakes- they are more forgiving.

And with a properly set-up disc/disc set-up, the braking forces stay proportionally balanced (all things being equal), which helps to diminish rear wheel lockup as weight is transferred to the front under braking, much more so than a comparable disc/drum arrangement.
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