WOOWOO RX7 Brake Conversion!!!

[Protege01MP3]

WELL It's finalized... I found a friend w/ a PIMPED OUT 3rd Gen.. just got FULL front and back brake upgrades... cost him about 5,000 US... and guess what.. hes gonna sell me his rotors and calipers... 4 piston calipers... BOMB!!!!!

For those that dont know.. ive had this idea for a while now.. a RX7 rear brake conversion... more for a kind of stealthy show mod... but they should add a nice performance boost to my stopping power... next will come the front big brake upgrade... (my head hurts when i think of how much full upgrades are )


so anyway... hopefully it'll be done pretty soon... next week or two and ill try to post pics and maybe a whole installation spread too... if i can borrow dads girlfriends digital camera... hey then i can get pics of my ride too.... didnt even think of that

 

[70]

How are you going to insure that the brake bias, and pressure is going to be the same??

You are going to have to change more than just rotors and calipers...

 

[promp3]

I was going to get pads and think I was hot s***.....basterd

 

[APEXistud]

Damnit, I clicked this post thinking that someone had made a brake conversion kit or something.:mad:

 

[Protege01MP3]

as i said.. this is a project... i havent gotten everything figured out yet... i was just excited that someone i knew had rotors and calipers for me.. so i didnt have to deal w/ dealership lag and prices.... i will upgrade other parts as well... and the guy w/ the 7 got a full on all around brake conversion, which means i can get other stuff i may need from him.. and whatever i cant.. i can always find aftermarket, or from the dealership (boooooo!)..

if anyone has any input (ahem, stutters) it'd be appreciated.

 

[JasonH]

If you do all four at once, the only difficult thing will be fabricating brackets for the new calipers, most likely. Do not just convert the backs or fronts and drive the car, unless you are using a tested aftermarket kit. The effect on your overall braking capability would be unpredictable.

 

[70]

as i said.. this is a project... i havent gotten everything figured out yet... i was just excited that someone i knew had rotors and calipers for me.. so i didnt have to deal w/ dealership lag and prices.... i will upgrade other parts as well... and the guy w/ the 7 got a full on all around brake conversion, which means i can get other stuff i may need from him.. and whatever i cant.. i can always find aftermarket, or from the dealership (boooooo!)..

if anyone has any input (ahem, stutters) it'd be appreciated.

Well, I'm no brake master, but I do know that changing out the calipers could seriously drop the pressure in your brake system. If you are changing out the calipers, you might need to look into the bake cylinder, brake bias valve, hubs, e-brake parts, etc. etc. etc. out of the RX-7.

Brake systems are designed very precisely, from where the leverage point is on the brake pedal, down to how much fluid is actually forced into the caliper.

Changing out one portion of said brake system could be overall damaging to the car. It could increase pedal force needed to brake, or even decrease the force needed. Either way. it could be bad.

The best way to upgrade your braking performance on the cheap is with good tires and good pads. Larger rotor size doesn't necessarilly mean better braking. Neither does four pot calipers.

Although they look cool, the might not be as good as you think.

There was a tech article about brakes in GRM about a year ago i think. It should be on their web site. I'll peruse it and see for sure, then post the link.

--- Edit ---

Ok, so here is one article...
http://www.grassrootsmotorsports.com/brakes.html

Its not the article I was looking for, but it'll give you some idea of what's going on in your brakes. I think the article i read was in the mag only, and so I have to try to figure out what issue it was.

It was a solid article with all the math that is used to engineer a brake system.

 

[jsesq]

I think a better upgrade would be to add anti-lock (ABS).

 

[APEXistud]

I think a better upgrade would be to add anti-lock (ABS).

ABS is awesome for safety reasons, but it's not all that great when the ABS kick in when you don't want it to. In example, braking over uneven pavement or braking while in the middle of a very hard turn. Some ABS systems are smarter than other, but in my best friends WRX, the ABS kick in at the most annoying points especially over uneven pavment. As it stand though, I would love to have ABS if I was still living in Michigan where the weather can play with while driving, but her in Cali it isn't so bad.

 

[Kooldino]

how much stopping power will slotted rotors add assuming your brakes are somewhat hot (or wet?)?

 

[20ESGUY]

Slotted's will only add marginal performance over stock IMO, theres really just not that much room for gas explusion, which is what the slots are for. Thats one reason that slotted rotors that dont have slots to the outside of the rotor do no good what so ever. If you wanna make a big difference add a good set of cross drilled rotors and some metallic pads. You don't necassarily have to have bigger rotors, just more effecient ones.

 

[jsesq]

I guess there are 2 different concerns here. One is high performance driving where ABS can be a detriment to maximum performance. However, you mentioned braking in the middle of a very hard turn. DO NOT DO THIS. Braking should accomplished prior to the turn. Braking in the middle of a turn will transfer weight forward and cause the rear-end to lighten and, if you are braking hard enough, will cause the back-end to slide out altogether. If you are braking hard enough in the middle of a turn to engage the ABS, you are going MUCH too fast.
The other situation you mentioned was rough roads where the bouncing of the car will trick the ABS into engaging (as the tires leave the road the brakes have no problem stopping the wheels, but the ABS sensors detect that the car is still in motion - so it uses ABS). Here I would guess that the ABS would feel strange, but I would be interested to see how it effected stopping distances.

The other view is for daily driving - here I believe that ABS is invaluable. Poor road conditions (rain, snow) can easily lead to lock-up and once the car is skidding, it is very difficult to regain control.

 

[big_ben]

Slotted rotors dont help the rotor stay cool. All slotted rotors do is "wipe clean" the pad every time one of the slots pass over it. Really and truely, there is no reason to get cross drilled rotors for a street driven car. You brakes will not heat up enough to need any additional cooling. The drilled rotors do look cool though.

 

[jsesq]

If you wanna make a big difference add a good set of cross drilled rotors and some metallic pads.

Be careful with drilled rotors if you are going to be doing any really hard driving or track events - the drilling process weakens the rotor and can lead to craking.

Make sure to check for fatigue regularly if you go with drilled rotors.

 

[big_ben]

If you wanna make a big difference add a good set of cross drilled rotors

I didn't even see that in that post. I have to disagree completely. I also have thermodynamics on my side to back me up. I'll give you a breakdown on how brakes work.

Brakes are basically a friction and heat transfering system. The brakes mash against the rotor and cause lots of friction thus stoppng the car. That friction causes a heat transfer into the air. Cars that are only involved in daily driving and weekend autocross events have no added benefit when using cross drilled rotors.

Go change your rotors to cross drilled only(not slotted), and try to get shorter braking distances, it wont happen. When you reduce the amount of surface area for friction(the drilled holes), you reduce the amount of stopping power. The only reason race cars use the drilled rotors is because theirs brakes are under lots of stress and heat up to 3 times the amout of normal cars. So the loss of surface area for friction is a trade off for cooler rotors so the brakes will still function. If you put them on this car, your stopping power will probably be reduced.

The only way you will see improved braking in a street driven car is to add sloted rotors. Your brake pads gather a layer of dust particles from the pad wearing away. This layer of dust prevents the pad from making full contact with the rotor. It is a microscopic amount, but it makes a big difference. If you have slots in the rotor, the slots will wipe off the layer of dust each time it passes the pad, thus giving the pad improved contact with the rotor.

Our rotors already have directional vanes in them which are more than efficient enough to cool the rotors. Don't get me wrong, I love the way drilled rotors look, but I will never expect any improved braking out of them. Just good looks.

 

[derrick1623]

the semi-metallic pads help, but they suck if they are "cold", it seems like it takes a few seconds to grab, until they get warmer.

 

[20ESGUY]

ben,

Sorry man but from personal experince and my own driving style the heat is the main reason I would do cross drilled rotors. I agree with you that the surface area is reduced and that they require more visual inspections than solids or just vented. The problem I have most often with brakes is green fade, which with full metallic pads, cross drilled and vented rotors, and some good hi-temp brake fluid I can correct that problem and reduce my stopping distances. I had always been under the assumtion that the cross drilled and the slotted rotors main purpose was for gas removal, since when you brake you build heat and the combination of heat and the brake pad material actually cause a thin film of gas between the pads and the rotor that will cause brakes to become less effective by pushing the pads off the rotor...hence green fade. Changing from the solid rear rotors and vented front rotors on the mx-5 I had to full cross drilled made all the difference in the world...I could actually stop vs. having the pedal dive to the floor. They may not be for everyone who just putts around town, but I think for people that drive with a fairly aggresive style they help quite a bit.

 

[big_ben]

I agree that the high temp brake fluid and the slotted rotor help greatly, but in my opinion the crossdrilled are for looks only in street cars. But everyone has their opinion and I can surely respect that. Do you have drilled rotors on your Pro? If so where did you get them?

 

[20ESGUY]

naw, I don't have drilled on the pro yet. Money is something thats been coming up short lately for mods. In time the pro will, I think I've finally got my final plan together, which includes cadium plated cross drilled rotors and if I can find them for the protege either EBC green pads or VGX full metallic pads...just depends on which one's I can find.

 

[jsesq]

. . .with full metallic pads, cross drilled and vented rotors, and some good hi-temp brake fluid I can correct that problem and reduce my stopping distances. . . . Changing from the solid rear rotors and vented front rotors on the mx-5 I had to full cross drilled made all the difference in the world...I could actually stop vs. having the pedal dive to the floor.

I am curious - you say that you reduced your stopping distance - I am sure that you have - but you changed too many elements to make a determination as to what is improving the stopping power and reducing the tendency to fade.

First, were the rotors the same diameter and thickness? Increasing either, or both, of these dimensions would increase the swept area and/or the ability to dissipate heat.

Second, you changed the pads.

I would guess that the (probably bigger) size of the rotors and the new pads were the biggest factors in your improved stopping power.

Third, the high performance brake fluid would reduce the tendency for the fluid to boil - which is the main cause of brake fade (or failure).