Has anyone done ABA testing with single rear calipers vs. dual rear calipers on a naturally aspirated 4.70 to 4.50 range dragster? Looking to understand how much if any adding a second caliper will slow a car down that runs say 4.70.

Thanks!

I'd be more worried about putting your dragster into the wall.

I would honestly say weight being the main factor, 100 pounds is roughly .07-.08 in the 1/8 mile, so if the brake system adds 10-20 pounds, you won't see much more than .01-.02, my nitrous system weighing around 30 lbs total really only slowed me down .02

As far as adding the second calipers, are you adding a handbrake/separate master cylinder as an added safety precaution/for use in killing a little more speed in the shut down without toasting the cars main braking system? If putting them on the same pedal, and same master cylinder I agree with Ed that it will lockup very easy and defeats the purpose if one brake line goes out, you lose the whole system.

The setup is a single master cylinder and 4 calipers. No hand brake, no second master cylinder.

I've raced this car with single and dual calipers, i prefer the braking action and precision with 4 calipers, staging is better for me with 4 calipers. They definitely have a ton more braking when you grab some but singles worked fine for 10 years or so. Added the second set of calipers when i went to the blower and liked the feel of the pedal and the application down track, removed the blower and kept racing the dual caliper setup and just got use to the feel and the braking.

Before you go saying pedal should feel the same you might want to do the test as i have outlined. Retrofit your car with dual calipers and let me know if you can tell a difference, i sure did. If you haven't done that then no need to comment about how i need better brakes, bigger or smaller master cylinder, swap brakes for xyz brand, different pads, new rotors, etc. If and when you do this test you will see the difference i'm talking about.

I'm looking to see if someone has run a car with dual calipers, removed a pair, and ran single pair of calipers on the same car, and what if any difference did you see. The question can also go the other way, if you had only single calipers then swapped to dual, did you see any change in performance.

The second set of calipers when i added them was a different backing plate and 2 additional strange 4 piston medium duty calipers, T in the brake line at the caliper, and line to the second caliper on each side. The weight factor here is only 5 to 10 lbs max. If there's any real difference here to me its due to the drag the caliper places on the rotor at speed. ideally these race brakes have zero drag but i just don't buy that.

On my altered I went to dual brakes with a separate master cylinder and hand brake and did not notice any difference in ET. Huge difference in safety factor in my opinion to have a separate back up system.

The only difference should be the added weight of the plate and calipers which likely won’t be enough to show up on a time slip. I can reach in and rattle the brake pads on my cars, I doubt there is any meaningful drag.

I’m not going to tell you the feel is the same but I will say I can lock the brakes up on either of my cars if I want to with single calipers. I don’t need or want any more brake action with the pedal.

A separate master cylinder on a hand brake is a great safety feature. 2 sets of calipers on the same pedal doesn’t help if you lose a brake line.

I agree on the second master cylinder deal for the safety aspect, that wasn't why i added them in the first place. Its holding a surging BBC with a 14:71 high helix blower in the lanes and actually making it stage where you want it to. This took a lot of convincing for me to believe but it works like a champ. They also come in real handy when cruising the pits to and from the trailer or when trying to put a little heat in the motor for the first run of the day. With a single set of calipers, the first day i warmed the motor up the brakes were smoking when i got back to the trailer, that problem was eliminated when i went to the dual caliper setup.

You are all correct about the safety aspect, but as i said that wasn't the original reason to add. I'm searching for some ET on this car and just wondered if the drag from the caliper was enough to matter.

183N i'm with you i could skid the tires in the lights if i over did it on a single caliper at the stripe, same thing on the dual caliper setup but what i did find is that i could get more stopping action before actually locking the brakes up with a dual calipers with less pedal pressure. For sure if you mash the heck out of the pedal with the dual calipers it was a slide fest but i did like how i could kill a ton without locking them up. Going back to singles for now we will see how things work out.

Thanks for the input.

Kris

quote:

Originally posted by 183N:
The only difference should be the added weight of the plate and calipers which likely won’t be enough to show up on a time slip. I can reach in and rattle the brake pads on my cars, I doubt there is any meaningful drag.

I’m not going to tell you the feel is the same but I will say I can lock the brakes up on either of my cars if I want to with single calipers. I don’t need or want any more brake action with the pedal.

A separate master cylinder on a hand brake is a great safety feature. 2 sets of calipers on the same pedal doesn’t help if you lose a brake line.

Agree 100%. My old car had 2 separate systems with a hand brake - I thought it was stupid when I bought the car but I miss it and would love to add it to my current car. In a dragster, it makes it much easier to unload the car or stop the rear wheels when running on jack stands. Besides the security of knowing that you can stop even if your pedal goes to the floor, If you are in the late rounds and start to feel an issue with your primary brakes you can basically just ignore it and continue to stage / stop with the hand brake without worry.

quote:

Originally posted by BD104X:

quote:

Originally posted by 183N:
The only difference should be the added weight of the plate and calipers which likely won’t be enough to show up on a time slip. I can reach in and rattle the brake pads on my cars, I doubt there is any meaningful drag.

I’m not going to tell you the feel is the same but I will say I can lock the brakes up on either of my cars if I want to with single calipers. I don’t need or want any more brake action with the pedal.

A separate master cylinder on a hand brake is a great safety feature. 2 sets of calipers on the same pedal doesn’t help if you lose a brake line.

Agree 100%. My old car had 2 separate systems with a hand brake - I thought it was stupid when I bought the car but I miss it and would love to add it to my current car. In a dragster, it makes it much easier to unload the car or stop the rear wheels when running on jack stands. Besides the security of knowing that you can stop even if your pedal goes to the floor, If you are in the late rounds and start to feel an issue with your primary brakes you can basically just ignore it and continue to stage / stop with the hand brake without worry.

I wish I could add a handbrake to my dragster, but the cage is very small and would take up to much room I fear. I would love to be able to use it when unloading and in the shut down I feel like I'm punishing my single caliper setup when stopping. I feel like after going through the traps and just laying into the foot pedal and the hand brake it would slow very nicely. I do know if/when I build a new car, it will have two systems for sure.

Brake drag is something to think about...

My car is way easier to push with dual M-W brakes compared to what I had before....4 Wilwood calipers with both Strange rotors and Wilwood rotors over the years.

Same 2 lb residual valves....

I always had issues on my first run with new pads on the old calipers....pads were too tight and a lot of drag and heat....I used to sand them down trying to eliminate that first run issue.....Stuff fit like crap....

M-W calipers/rotors fit perfect, no drag period...


I added the hand brake and it's not pretty but it works fine and yes it makes unloading the car very easy by myself....and I use it to stop as well if I feel like it......just alternate from foot to hand and I use the handbrake in the pits a lot....

[/QUOTE]
I wish I could add a handbrake to my dragster, but the cage is very small and would take up to much room I fear. I would love to be able to use it when unloading and in the shut down I feel like I'm punishing my single caliper setup when stopping. I feel like after going through the traps and just laying into the foot pedal and the hand brake it would slow very nicely. I do know if/when I build a new car, it will have two systems for sure.[/QUOTE]

It will, but the problem with that is that you will kill the rotors - you're making one rotor deal with the heat and friction of 2 calipers.

Just alternate from foot to hand.

I do that to try and even out the pad wear....it doesn't work though..

Foot always wears out more than handbrake...

If you have to you can use both at the same time but it's not usually needed.

My car had single calipers and the Strange rotors were lettuce shredders not long after I got the car.....split right out to the OD of the rotors at the slots....dangerous junk....

Just my experience, in the 3 or so years i ran dual calipers it appeared the rotors looked surprisingly good. I'm thinking its because you have two calipers to dissipate the heat through vs. one. Another thing is with dual calipers applying at the same time its less temperature but the same heat/energy dissipated when stopping. Dual calipers gives more mass to transfer heat, the second set of calipers. Without a second set, all the heat has to go into one set of pads and one set of calipers and of course the rotor.

Just seems on this car the rotors are in better shape than in previous single caliper setups i've had on this same car. Then again i've not made nearly the runs on dual calipers as i have on singles so my baseline for the evaluation is a bit skewed.

quote:

Originally posted by Triple Nickel:
Just my experience, in the 3 or so years i ran dual calipers it appeared the rotors looked surprisingly good. I'm thinking its because you have two calipers to dissipate the heat through vs. one. Another thing is with dual calipers applying at the same time its less temperature but the same heat/energy dissipated when stopping. Dual calipers gives more mass to transfer heat, the second set of calipers. Without a second set, all the heat has to go into one set of pads and one set of calipers and of course the rotor.

Just seems on this car the rotors are in better shape than in previous single caliper setups i've had on this same car. Then again i've not made nearly the runs on dual calipers as i have on singles so my baseline for the evaluation is a bit skewed.

This is my thinking, I don't want to slow down any faster, just not have to abuse the foot pedal brakes as much as the hand.. But then if needed to stop quicker, it would be much easier to grab a little of both systems and the car would definitely slow down in a hurry if need be in certain situations..