Miata Turbo Forum - Boost cars, acquire cats.

i answered this a while back. check the "does anyone have any braking questions" thread.

Quote:

Originally Posted by OGRacing (Post 1178300)

Quick Rant about braking systems and Journalists..
a few months ago jalopnik posted an article about upgrading a miata to sentra brembos. I was pulling my F*%king hair out when they did this. rule 1 they didn't center the rotors. They are going to blow through wheel bearings. rule 2 they didn't even look at the piston area of the calipers. the sentra has a 38x42mm piston Dim. that equals out to 3.9in^2 of caliper area. A factory miata has 3.17in^2. sure that doesn't sound like allot. until you realize it's 23% larger. that combined with the larger rotors you'll have 25-30% more Brake torque on a chassis that has over weighted front brake bias. This is Stupid, Dangerous, and incredibly irresponsible. the thing that pisses me off about jalopnik journalists is that they really don't give a shit, if the do care they are f&$King retarded. all they want to do is throw some words onto a blog and to-hell with people that die following their advice. They have taken the idea of let's spend money to make this worse, to an extreme. But hell, now it says brembo.. :crx:

that is true. Allot of manufacturers will keep a knuckle or the caliper bolt pattern and offset to aid in some kind of cost saving measures. i actually have no idea why they do that. but they do.

Remember in a braking system "more" is not better, it's just more. remember we are trying to build a complete a braking package.Taking a caliper from one car, and adapting to the other. before you do this you need to take some considerations into account. piston area in the calipers, Rotor offset, and overall braking balance.

Piston area.

Brake Tq can only be changed by 3 Dynamics in a brake system, Rotor Size, Pad compound, and hydraulic advantage. Hydraulic advantage the difference in size between your master cylinder, and your caliper pistons. if you want more Tq increase your pistons, less decrease your pistons. same goes for the master cylinder. you want more TQ? decrease your Master cylinder size. it will increase your hydraulic advantage. ***before we go out messing with master cylinder sizes and piston sizes there is a point of no return.*** the aspect that nobody thinks about but is important has to do with the brake pedal. As a pedal travels thru it's motion you do lose some advantage the further away from the driver it gets. We find at almost 90* on most pedal assemblies the driver would lose leverage. loss of that leverage would make the pedal harder to push. by decreasing the master cylinder size, or increasing piston size you're increasing the distance the pedal needs to travel. so it will take less effort from your foot to stop, but your trading that effort for pedal distance. try and keep the sweet spot of the pedal (@90*) at the point of where you start to modulate your brakes.

Rotor offset

Deceleration happens exponentially faster than acceleration. think of our miata's, with 500hp almost every stock component will snap under that much power and acceleration. every miata can decelerate 4x faster than a 500hp miata can accelerate. the idea that i'm trying to put into everyones mind is 2000hp but in reverse. Everyone would agree that is allot of force. that's the force your braking components are under. When we design a big brake kit, the rotor needs to be squarely centered in between the hub bearings in order to stop the bearing from getting torn to shreds. as an example of what not to do, I bring up the unnamed unethical corvette shop again. They built their own big brake kit for c5/c6 corvettes and proclaimed it was "better than brembo.". that was a fed flag for me because brembo is a multi billion dollar a year brake company, and these guys are 4 idiots with a cnc machine. first question i asked them was "did you center the rotors in between the wheel bearings?" they answered with "why?", to me that means 'NO we didn't think of that'. every kit they installed on peoples cars blew out one skf corvette wheel bearing ($300-$500ea), this happens at every event. so make sure when you go to an non-oem rotor that the rotor offset is identical.

Overall balance

Big piston calipers, huge rotors can make your braking system feel like complete garbage. A personal example. before i was a brake rep or knew anything about brakes, i did a track day. i took a set of porter fields street pads out and burned them up. I absolutely cooked the snot out of them. They didn't like to work, but they would slow the car down. I knew the pads where toast, so i ordered a set of hp+ pads. I couldn't tell you why i ordered fronts only, and left the toasted porterfield pads in the back. I bedded in the hp+ on the street and thought "man these feel much better.". I went to an auto cross the next weekend. The track started with a long straight followed by a sweeping right turn. first run, I charged hard, came to the braking Zone, reached for the brakes, and there was nothing but white smoke. I flew 10 yards off the track and into a berm. Two big black marks from my front tires lead all the way off the track. My Front tires had all the braking power in the world, the rears were nowhere to be found. to put it into engineering terms the Fronts where at 90% braking and the rears were around 10%. the new pads had an increase of 30% more TQ, to yield to 90% worse overall performance. Although i had "upgraded" the Front brakes, it gave me worse performance than if i had left the burnout pads on the car. Yes you can increase the caliper sizes and get more torque out of the front wheels, but without balancing that increased TQ to the rear you're going to make the braking performance (ability to slow the car) worse. the Idea out of a braking system is that you want to use 100% of the tires. 100% of all 4 tires to slow the car. as the car stops weight is transmitted forward. at this point the rear tires have less weight on them and less traction. my point is that,it is not hard to upgrade rear braking components to handle the lightened traction. but everyone seems to forget that we do have brakes on the rear of the cars that need love too.

to answer your question. yes, you can bolt allot of equipment onto "other" hubs. without balancing the equipment out F->R then you're not really building a better braking system. make sure those rotors are centered. or the money you save avoiding an engineered brake kit will go toward wheel bearings. watch out for how much you increase piston area or you might need more pedal stroke than is available to you.[/QUOTE]