60 to zero braking distance

[ks71z28]

Anyone got the data? I used my g-tech Pro RR, my b-body 12" front discs with Wilwood GMiii calipers and t/a rear disc 71 camaro stops in 165-170' with Hawk HP plus pads. Not all that steller. If pushed harder I may get the stops shorter. I use a dual diaphram booster and 1 1/8" master with adjustable prop valve. The G-tech is consistant. I can creat graphs and overlay runs. They have been near identical. With sticky Kuhmo tires I can't lock the wheels. So what are your numbers?

[dustinls1]

that's not ground breaking braking performance, but it's a pretty heavy car, and those big GM calipers are know for lots of flex. First thing I'd look for is if you've got enough pressure at the caliper. You should have 800-1000 psi. Usually the culprit is low vacuum, 18" of manifold vacuum are required to run that booster, regardless of what the booster salesman says.

[chicane67]

I got my 67 with (then) factory 4-piston 'D3' calipers/drum rear down to 119 or so with Andys R4S compound.

With the new AP 5555's I am looking at going under 98ft......

[Jeremy]

I am around 110 foot using a cone for a braking starting point and then measuring from there. This is in an 80 TA with stock discs front and rear using Wilwood GM III calipers front and rear. I use Albany Semi metallic pads. Tires are 275/40/17 Goodyear F1.

[ks71z28]

I may try the cone trick to see how acurate the g-tech is. thanks for the input guys. By the way what do you use for an E brake on the rear if you have the gmiii calipers? I have a manual trans and need one.

[yody]

I got my 67 with (then) factory 4-piston 'D3' calipers/drum rear down to 119 or so with Andys R4S compound.

With the new AP 5555's I am looking at going under 98ft......

so your cars going to be running now?

[Jeremy]

Right now I am not running an e brake. This winter I hope to get a pinion mounted e brake set up.

[jeffandre]

Right now I am not running an e brake. This winter I hope to get a pinion mounted e brake set up.

I have a pinion-mounted setup, should work fine once a cable is hooked up to it someday. I bought it from Eynstein (a Chevelle guy) a few years ago. I had to do some work to get it to fit my particular 10-bolt, but I have heard fantastic things about these ebrakes from truck guys.

[Jeremy]

That's who I plan to buy my setup from. I like it in that it totally seperates the ebrake from the rest of the system. I also like how simple it looks and that it lets me run calipers and rotors that I want without concern for the ebrake.

[BRIAN]

What size booster?


110 feet with drums on the rear?? I checked my R&T and the best of all the cars they have tested was about a 109 feet.


I would think anything near 125 is good for that set up.

[Steve1968LS2]

I got my 67 with (then) factory 4-piston 'D3' calipers/drum rear down to 119 or so with Andys R4S compound.

With the new AP 5555's I am looking at going under 98ft......

98ft is really short.. that must be a blast..

What tires?

[CarlC]

127' with stock single-piston GM calipers, el-cheapo semi-metalic pads and rotors, stock drums with standard shoes, 16" BFG Comp ZR's. It stops much better now.

The real test is to do 60-0 five times as fast as possible and compare.

Tires and road surface make a HUGE difference.

[fuzzyonion]

Wilwood GMiii calipers and t/a rear disc

What year T/A? Try changing to a smaller diameter piston rear caliper (max of 2.125") and smaller master (max 1").
I base this on the listed size of the GMIII caliper of 2.38" diameter.
Larger diameter disc will not make up for a smaller caliper piston.

[ks71z28]

I have the 2.75" fromt willwood single piston calipers, and the rears are the 78 only seville large 2.8" piston units. i would like to swap them out, but that requires changing everything but the rotors, the later ones use the metric size caliper.

[Norwoodx55]

Does anyone have the current web add. for the Enstein pinion E-brake set up? The one I found in a search was expired.
Thanks, Brett

[Jeremy]

I am still learning about braking basics so bear with me. I assume the smaller master cylinder would give more brake pressure. What MC has a 1 inch bore and bolts to a stock GM power booster?

What benefit would a smaller diamter rear piston give?

[jeffandre]

Does anyone have the current web add. for the Enstein pinion E-brake set up? The one I found in a search was expired.
Thanks, Brett

I tried looking for Pete Lohr's site with no luck. I emailed him to ask permission to post his email address here if he is still making the pinion-mounted ebrakes. If I had a 9" rear I would have had a number of options, but at the time Pete was the only one making the setup for my 10-bolt. Not sure if anybody else does yet or not.

[fuzzyonion]

I am still learning about braking basics so bear with me. I assume the smaller master cylinder would give more brake pressure. What MC has a 1 inch bore and bolts to a stock GM power booster?

What benefit would a smaller diamter rear piston give?

Short version: Braking is a balance act. In most cases, the front brakes do 60-80% of all braking, so you want a larger piston area up front than in the rear, or you will not have efficient braking. The difference in sizes, as well as factors like weight transfer, pad coefficient, and rotor diameter, to mention a few, will determine your balance, and whether or not you need a proportioning valve, and how that valve should be set.
Most mid-size, front engine, RWD vehicles benefit from about a 65/35 split, usually with a prop valve.

The master cylinder size will depend on pedal ratio and caliper displacement. The largest master cylinder possible should be used with respect to how hard you are comfortable pushing. A smaller bore will increase line pressure with respect to foot pressure, but it will also increase your pedal travel. Another thing to consider in a master cylinder is its stroke. If the bore hasn't enough stroke, you might bottom out the piston before you reach full pressure to the calipers.

70 Corvette and 70 camaro both have 1" masters for their manual disc brake applications. Either could connect to a stock power booster. The Corvette one would work on a long pushrod style booster, the Camaro a short.

-----------------------------------------------------------------------------------

the rears are the 78 only seville large 2.8" piston units

The last 78 Seville rear calipers I looked at appeared to me to have the 2.5" piston, though it did take the regular D52 pads. IMO if it actually does have the larger 2.9", I would change them even though it means work and money, if you want to stop well.
If it has the 2.5", they should be fine.

[ks71z28]

WOW, I never measured the piston size. I assumed that it had the large piston since it used the d52 size pad. I must check it out! I base lined my car with my 68 Firebird which has power front disc/rear drum, all stock. It stopped at 150-155'. I used cones to check the accuracy of the g-tech. It was as close as I could measure with cones and a tape measure. THe camaro actually came down from my earlier number of 165 to the magic number of 150', but..... I had too much front brake, causing the fronts to lock up with in approx 40' of application. I didn't realize the car was skidding the fronts to that extreme. The result is flat spotted tires. Yeah it was an expensive day. With a few turns of the prop valve the car ought to stop shorter. I had to cut the test shot due to pissing people off.

[gen3bu]

a 1993 s-10/sonoma has a 1 inch master. i switched mine to a 1995 c1500 1-1/8 master and it stops a lot better. i also removed the abs and prop valve when i switched the master and the rear brakes actually work now. i have been driving it like this for 3-4 years now with no problems.