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RX-7 2nd Gen Specific (1986-92) RX-7 1986-92 Discussion including performance modifications and technical support sections. |
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10-03-2008, 09:37 PM | #1 |
Rotary Fan in Training
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EVO brake conversion, front and rear.
The front EVO brake conversion is being done and documented by a few FC folks. Here I will cover both the front and rear conversion I am doing to one of my FCs.
Feel free to ask questions or offer criticism based on your own experiences. We'll start with some pics and brief descriptions. Rotor comparison, stock on the left, EVO on the right. Front on the top, rear on the bottom. Rear on the left, front on the right. Calipers, EVO front and rear and factory 4 piston Front EVO caliper and rotor mounted on FC spindle. The rotor has been turned down roughly 1/8" in diameter to just under 12 1/2" and the center bore has been enlarged to fit the FC hub. The calipers require swapping the bleeder screws and transfer tube from end to end. This is due to the EVO caliper's staggered piston diameters and their orientation on the EVO. They are mounted on the front side of the axle from Mitsubishi and get pushed to the back on the FC. The first thought is to just swap them from side to side in order to keep the bleeders on top, but because this places to pistons in the wrong order under rotation they must be keep on their correct sides. So the bleeders must be switched to the top and the transfer tube to the bottom. Modified front knuckles. Close up of mounting ears. The threads are drilled out with a 12mm bit so the bolt now passes through the knuckle and threads into the caliper. The mounting surface has been milled down .035" to properly center the caliper over the rotor. Rear rotor on FC hub. Because the EVO rotor's center bore is larger than the FC's I machined a spacer to take up the space, very similar to a hub centric spacer for aftermarket wheels. It was rough cut from a piece of 6061 1/4" thick aluminum plate with some hole saws and then finished on a lathe. The only machining required on the rear rotors is on the parking brake drum area. It protrudes from the hub a bit to far and interferes with the knuckle. Rear knuckles. Here is where many people will shy away from this project. The original caliper mounting ears are cut off and a new bracket cut from 1/2" thick 6061 aluminum is welded to the knuckle. The bracket rests very well on a flat surface on the backside of the knuckle and will require less than .040" of shim to locate the caliper correctly over the rotor. The two allen head bolts are only to hold the bracket in place during the welding, I just left them in place afterwards. |
10-04-2008, 08:47 AM | #2 |
My minds tellin' me no...
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That seems like a ton of work and custom fabrication for something that will not be of use to 95% of FC owners.
When all is said and done, how much is this going to cost to get done. I know the Evo parts can be sourced cheap, but the fabrication is where the serious $$$ are going to be spent, not to mention all the new bearings and seals which will need to be replaced due to the complete tear down of both front and rear spindles. My .02.
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10-04-2008, 03:36 PM | #3 | |
Rotary Fan in Training
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Quote:
I'm posting this for the folks researching different options for improved braking. No one that I know of has tried using the rear brakes from the EVO for the reasons you posted. But some people may want to make it happen, this is only a guide of how I am doing things to help others in their quest for improved braking. |
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10-04-2008, 03:44 PM | #4 | |
FUCK the fucking fuckers
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Crazy custom work! That's a lot of brake. What are you doing with the car, as a whole?
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10-04-2008, 03:56 PM | #5 |
Rotary Fan in Training
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10-04-2008, 03:57 PM | #6 | |
FUCK the fucking fuckers
Join Date: Mar 2008
Location: THE only Bay Area, Northern California
iTrader: (7)
Posts: 3,172
Rep Power: 20 |
are you going to disable the ABS? I know some people with bigger brakes have front lock-up issues with the ABS.
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10-04-2008, 04:06 PM | #7 |
Rotary Fan in Training
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10-06-2008, 04:57 PM | #12 |
Rotary Fan in Training
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I have looked at a few OEM master cylinders but will probably go with a tandem setup with an adjustable balance bar. I will cover the hydraulics here when I get to that point.
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11-05-2008, 07:57 PM | #13 |
Rotary Fan in Training
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I've been too busy on other projects to get much done with the EVO brakes. But I did get a chance to fab the front brake cooling duct adapters.
More to come as my schedule allows. |
11-06-2008, 10:35 AM | #14 |
Reliable Source
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I've seen a similar setup on 240sx's, they only require a washer to bolt up evo rotors and sti calipers on the rear and the front needs a 3 inch shim with 2 holes in it to bolt up the sti front calipers on evo rotors.
that car must brake incredibly well. |
11-06-2008, 10:50 AM | #15 |
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and hell I removed my backing plates lol..
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