The Skinny on Brake Upgrades

[SlingShot]

Hey Guys, I'm researching brake upgrades to perform on my GTX. Would like to do all 4 corners.
I have searched the forum, and have not seen any good build ups on the 2nd gen RX-7 caliper upgrade for the BF.
I think this would be a very good upgrade to the GTX, considering that a lot of people think the VR4 upgrade is average.
My brakes are not too shabby, but would like to have all the right parts to perform the upgrade when the time comes. So let me know what you think.

Any and all brake info is appreciated.

[azgtx]

Search the yahoo 323 GTX forum and look for posts by Daniel Roy. He did it and it looks to be quite extensive. RX-7 4 pots and I think it was lexus rotors. You could get in touch with him and he might put one together for you. HTH

Clay Volz
Mesa Az

[jay]

vr4 is much easier than getting those rx7 to fit but yes it can be done, if Dan can't help out lemme know and I'll see how my pal who did it to his car remembers.

[trailrider098]

I did the galant swap with a 929 master and 626 booster and I am very happpy with the results

[Rocketman]

I did the Galant upgrade on my Capri XR2 (BF) and its the best mod for handling I've ever done. Car now stops on a dime, and its a challenge to get the brakes to fade. You know how bad the stock brakes are. It offsets the wheels a bit and for me the extra stance helped out handling quite a bit.

If you have access to a metal lathe its real easy to turn down the hubs to fit the rotor hat.

Comparison:

Galant rotor on modded hub next to stock XR2 hub...

[ryan1]

I did the galant swap with a 929 master and 626 booster and I am very happpy with the results

what year 929 master cyl?
what year 626 booster?
i just picked up a 88 gtx and the master is cracked, so while im doing the
boosted bp swap i might as well upgrade the boken stuff anyway.

[ryan1]

vr4 is much easier than getting those rx7 to fit but yes it can be done, if Dan can't help out lemme know and I'll see how my pal who did it to his car remembers.

i would like the info too if you can help, i have done the brake vr4 upgrade, but later i would like to do the rx-7 swap. i have also talked to Daniel Roy about it on the yahoo forums.

[jay]

Just heard back from him, his conversion involved fwd hubs, saab 9000 rotors, Wilwoods in front and rx7 calipers in back, a lathe, and a milling machine.

[SlingShot]

Just heard back from him, his conversion involved fwd hubs, saab 9000 rotors, Wilwoods in front and rx7 calipers in back, a lathe, and a milling machine.

Thanks for the info. Took AZGTX"s advice and tracked down Daniel Roy, his RX-7 upgrade looks very nice and for a fair price.
I'm kind of getting the urge do something different... maybe mock up some Brembo Calipers off of an EVO8 or STI.
Anything can be done right?

[pikespeakgtx]

The brembo calipers are too large in physical size for packaging into a GTX. They're made for 17" wheels more or less.

The rx-7 calipers will work great. You just have to fab up a triangular bracket deal-o. The FWD spindles have a closer stock caliper mount holes. BUT the steering arm is shorter than a GTX one. So you'll likely get some extra bumpsteer and I reckon you'll need to get different tie rod ends that are extended or get adjustable ones.

If I went with RX-7 calipers I'd use 96 nissan altima rotors. I've solid modeled all the parts needed to make the RX-7 brake upgrade using those rotors but never really saw the point in going that route. Although it would be a great improvement over the stock brakes.

I went a different route and used wilwood radial mount dynapro calipers and much larger full floating 2 piece rotors on my GTX. My first set isn't quite done yet. Still a few machining operations and then anodizing the rotor hats and painting the rotors to prevent rust. It fits under 15" wheels too.

And if you think turning down the hubs to size in a lathe is real easy...do it yourself. It's not what I'd call easy. With an interrupted cut and hardened high carbon steel hubs it makes turning a challenge because the material is nearly as hard as HSS that you're cutting it with. There's no clear winner. Sure carbide cuts better but the interrupted cut destroys carbide if you get greedy over over do it with cutter engagement.

Now, real easy is turning delrin using carbide tooling.

In a regular garage a 6" electric grinder will do the job of getting the hubs to fit inside the rotor nicely.

[jimbob]

how much is this set up costing you? (wilwood set up)

[jay]

What's kept me away from these conversions is the bracket thingie. I do not want to add a failure point to my brakes, thanks anyhow...add a torsion point, mess with the geometry, put unaccounted loads where they don't belong, gives too many chances for bad things to happen.
My pal's gp5 Volvo is a case in point, too many revisions to the front end resulted in a bearing or caliper mount failure, where the caliper grabbed the rotor on a straightaway at 120 mph a

[jay]

What's kept me away from these conversions is the bracket thingie. I do not want to add a failure point to my brakes, thanks anyhow...add a torsion point, mess with the geometry, put unaccounted loads where they don't belong, gives too many chances for bad things to happen.
My pal's gp5 Volvo is a case in point, too many revisions to the front end resulted in a bearing or caliper mount failure, where the caliper grabbed the rotor on a straightaway at 120 mph and rolled the car 7 times. He now has all Sellholm parts that are designed for that chassis.

[pikespeakgtx]

There is no "setup". I made the setup. Wilwood calipers and stoptech rotors are available in better parts stores everywhere. The rest I made here in the shop.

I've got a 929 master cylinder and a booster from a 626 on hand. You can get these as better junkyards everywhere. Remember to get the banjo fittings from the 929 master and the 1 way check valve for the vacuum line to the booster.

The stock MC bore is 7/8", the 929 is 1", they also have a 15/16" one that might serve the purpose even better than the 1", have to check and see. You can tell the bore size as it's written right on the top of the MC.

Remember this. Now pay attention. Larger caliper bores will increase stopping power. More surface area at the same pressure in turn increases the pressure exerted on the brake pad. But you get more brake pedal travel as the cost.

BUT changing the MC to a larger bore does just the opposite!!! It decreases the stopping power. By spreading the load out over a larger bore area the pressure thats able to be generated is less than a smaller bore size MC. You can more more volume of fluid but the pressure generated is less.

You go up in MC size when you're running out of pedal travel. Mazda was nice enough and gave us 3 different sizes to choose from. So find whats right for your setup and you're golden.

[jimbob]

ok i was just wondering how much you have put into them is all.