'85 GSL 302

I know this info has been posted before, however all the references I found were kind of confusing and I'm still not quite sure what the final answer is.

I'm looking for an upgrade for my '85 GSL brakes. I'd like to run a larger rotor and some bigger calipers. What are good upgrades for these cars? I've seen the monster big brake kit that's like $2000 and that's a little bit overkill for what I want. I'l like to be in the $600 range and have something that isn't going to fade out on the track. I'm pushing more weight with my engine, so I have to compensate with some better brakes. I've heard of people switching the 2G RX-7 front rotors but it seemed like there was a lot of work needed and the article i read didn't go into much detail. I'm basically looking for the next step after good pads and ss lines. So, what do you guys got?

CHEF_EG_1

OEM rotors and Porterfield R4S pads.


That car STOPS. I can lock the brakes in almost every turn of autoX. I love it.

31rx7

Before going to swapping out a bunch of stuff, there are some things I would suggest that are not all that expensive.

As suggested in the previous post, go to better pads front and rear. Look at Hawk, Performance Friction, and Porterfield. Based your driving situation habits, choose a high stopping power pad that warms up quickly.

Consider directing air to the front brakes via ducting. Mazda Motorsports sells a nice backing plate (part number 0000-03-7301-01) to connect the ducting to, but there may be other less expensive options.

With the extra weight up front the stock your brake bias is probably not right. Install a Wilwood brake bias adjuster and adjust the bias so the front and rears lock up in unison under hard braking.

Also, consider the suspension. Not sure about your spring / shock setup, but with the extra weight your nose is taking a big dive under braking which allows more weight transfer to the front. Stiffer front springs / higher rear shock damping on rebound will mitigate this, but be careful: obviously when you change these things, it will also impact your handling.

Similarly, if your front ride height is lower than the rear, either raise the front or lower the rear. Again, be careful as it will also impact handling.

Finally, a relatively inexpensive swap is going to the GSL-SE (13b engine) brakes, hubs and rotors. These are slightly larger and more effective than the stock GSL units. This also means you need to run different rims as the bolt circles are different. I am not sure if the Master Cylinders are different, but you may need to swap those also.

Best of luck!

Rich

JIMMY54

iTrader: (2)

Here's what I got,



Took awhile to install everything but it all works great!

JIMMY

hope that helps

'85 GSL 302

It would help if you told me what it was instead of just showing me pictures of shinny things

JIMMY54

iTrader: (2)

Well the "shinny" circle things with holes are called rotors, they spin and the brake pads apply pressure to these spinning "shinny things" and when they stop spinning, your car stops moving.

They are brembo blanks, drilled with the new computer generated drill pattern.

inittab

Aren't x-drilled rotors just for appearance? You know "all show no go".

JIMMY54

iTrader: (2)

Heat dissipation, other references you could look at for example, porsche, ferrari, lamborghini, any touring car series/road race.

'85 GSL 302

Bah, it's pretty well accepted now a-days that a good internally vented rotor will cool a lot better than a cross drilled one because the mass lost from the holes will actually be better used absorbing heat from the pads. Basically they're just for the sporty look on a street car. Real race cars use carbon rotors that they replace more than the pads. Think about it, a Porsche just wouldn't look nearly as cool without some big nasty cross drilled rotors stairing at you through the rims.

'85 GSL 302

Bah, it's pretty well accepted now a-days that a good internally vented rotor will cool a lot better than a cross drilled one because the mass lost from the holes will actually be better used absorbing heat from the pads. Basically they're just for the sporty look on a street car. Real race cars use carbon rotors that they replace more than the pads. Think about it, a Porsche just wouldn't look nearly as cool without some big nasty cross drilled rotors stairing at you through the rims.

jimmdog

I help my friend race a E Prod scca car. At the track there are probally 75 spec Rx7s that run. The biggest failure item is the front brake rotors. I have seen them crack all the way through. Go with the SE set up, cryo treated power slots and hawk pads your also gonna need the brake bias adjuster. Only go with cross drilled if you go with bigger rotors. My 2 cents good luck

JIMMY54

iTrader: (2)

how much does a brake bias adjustor go for? Who makes them?

rx7gslse

Dammit Jimmy... you know I'm *still* trying to find those rotors? No one aroudn here seems to be able to find anything close...

you getting them cryo'd?

JIMMY54

iTrader: (2)

No cryo... already installed.

Check these places...

KVR
Powerslot
Brembo
Eurorotor

They all have the disc's. Brembo seems to have the fastest avaiblilty around here. The rest were about 1 to 2 weeks of waiting. Brembo was 2 days w/drilling.

JIMMY54

iTrader: (2)

P.S. you reuse your wheel studs. And you have to change over the bearing seats in both the front rotors.

So you'll need a mallet and a thick punch to pop them off the old rotors.

And you'll need the grease seal off the old rotors also or get new ones.

Total cost for me was $736 cdn, and 2.5 hours of install.

I have KVR brake pads and DOT 4 brake fluid.

The car stops nicely!!

Junia

I don't know if this helps you stop better but I know that a master cylinder stopper makes the brake pedal feel a little "better" for a lack of a better term. Also, when you install larger brakes you can upgrade the master cylinder with a later model rx7 one maybe(this I haven't tried on a mazda but have on a nissan)

rotor vs. piston

I have a converted 7 as well (see sig) and I foung swapping to a GSL-SE set up did the trick for me. I still need to get some better pads, I'm using new Bendix pads for the time being until I get other things sorted. But when I put the middle pedel down now the car stops with a quickness.

JIMMY54

iTrader: (2)

Mine is a SE model, the biggest improvement came with changing to DOT 4 brake fluid. 500F temp rating.

I used to have alot of brake fad in the pedal, but now with drilled brakes/DOT 4/KVR carbon kelvar pads, I haven't experienced any fade yet.

JIMMY

AJC13B

https://www.rx7club.com/forum/showth...hreadid=167200