Kenku

Okay, I've got a question. I know the GSL-SE rotors are bigger than the GSL ones, but how much? Also, I've heard rumors that the spindles are the same between the 84-85 RX-7s and the 2nd gens... so the hubs would be a bolt-on swap? I've figured out how to get a caliper mounted, I'm just wondering how to get different rotors. The better bolt pattern's sort of a consideration too.

Oh yeah, to all of you wondering why I want to do this, there's a few reasons. First, I'm wanting the better bolt pattern. I mean, duh. Secondly, I know that the stock brakes are excellent and can stop the car really fast... but I'm planning on eventually having ungodly amounts of power, and I'd like to have everything prepared for it in advance. No getting up to ludicrous speed and then finding that I can't slow down fast enough.

So what should I think about? GSL-SE brakes would be easy if I can find 'em (obviously) but 2nd gen (especially turbo!) brakes would probably be beefier yet if I can make 'em fit. Opinions?

Kenku

Hate to do this, but *bump*. C'mon, isn't there anyone out there who's played with different brakes on the 1st gen?

Maybe I should just go hit the junkyard. Have to get the race car back together though...

BadAssRX-7

WELL if you have "ungodly power" you want to go get the bear big brake kit... they have a front and a rear kit... 1300$ for the front only OUCH and the kits require a min. of 17" rims

Kenku

Funny... hitting the Baer site, the only Mazda they offer brake upgrades for is the Miata. Have to wonder where you're seeing this.

I've found two big brake kits for the first gen RX-7; the Selectmaz kit, and the one that's offered by 7's Only Racing. The Selectmaz kit is only available for S1-2 RX-7s or earlier, and only in the 4x110mm bolt pattern, and the 7's Only kit I didn't get a reply back to my emailed enquiry. So I'm trying to figure out how to do it myself.

If you can point me at any other brake upgrade kits anywhere I'd be happy.

Forseti

THere's definitely a difference, especially with the rear rotors. Check the online FSM for the info on this.

That's exactly a rumour. Perhaps some of the S4 NAs had similar spindles but the S5s were 5-bolt and won't work.

I found a lot of good gsl-se brake parts right here on the forum or on the partstrader used. Victoria British also has reasonable prices on GSL-SE brake parts.

Going to 4-piston calipers (like the TIIs) would be overkill in my opinion and I'm not sure how well your hydraulics would be up to the task.

<F>

Kenku

Well, spindles I was talking about, not hubs. And I might have to keep thinking more about the -SE bits, though I almost definitely won't be using a Mazda rear end by the time I throw the 13B in it; I'm trying for around 300-some HP before any boost and from what I've heard the 1st gen 3rd members aren't durable enough for that.

4-pot calipers would make a new master cylinder necessecary too, so hydraulics not being up to the task... well, I thought of that.

... hm. My curiousity is getting the better of me. I wonder how much the local boneyard would want for one of the front hubs from their '86 RX-7.

diabolical1

iTrader: (3)

Okay ... not trying to be a tool here, but I'm not 100% clear what you want.

From the previous posts I gather that you're looking for more stopping power to go with your plans for more horsepower, and I thoroughly commend that! Not enough people think like that, but ...

Two things concern me: This part is the first ...
Are you planning to use forced induction on a peripheral port or something? 300 HP BEFORE boost??? Not sure what you're thinking, but I will say stop thinking it now! If there's something I'm missing then I apologize and please enlighten me ...
The rear ends will hold up for spirited driving and the occasional drag race. I've seen a regular GSL rear hold 550 HP (flywheel), but that was a friend's car and it was still alive up to when he sold it. He raced it pretty often, too. I think your biggest issue is choosing the right clutch because I've seen 170 HP (flywheel) tear up a GSL rear! So for what it's worth keep that in mind.

The second point of concern is how much of your setup have you actually planned (meaning parts and part-combinations) that you have actually confirmed and can "yes, I'm definitely going to do this?"

I'm asking that because the SE brakes with the right pads and some SS lines (and believe it or not, the right tires) are pretty good for stopping a Gen I car with 250+ HP. I can't speak for across the 300 HP mark, but I can speak for 250+. So unless you plan serious road racing, my opinion is that you won't need to go with an aftermarket "BIG" brake kit.

About the regular brakes vs. the SE brakes:

Non-SE (f/r): 8.94 in./9.29 in.
SE (f/r): 9.84 in./10.1 in.

I don't know if the front spindles are the same on the Gen I and Gen II cars, but I seriously doubt it. However, I can tell you for sure that the rears are different. The Gen II Rx-7 SE (not to be confused with the Gen I GSL-SE) used the same brake rotors and I think the same calipers as the SE though. However all the other models/variants used different rotors (5-lug).

I hope this helps you out some ...

1

Kenku

Hmm, I didn't realize that the fronts were *that* much bigger on the SE. Eeeexcellent. That *IS* helpful.

As to how to get the horsepower... ever seen pics of the Scoot PPort secondary motor? I've talked to Rice Racing on here and thought about port timing a lot. I've got a '91 NA engine out in our barn that's going to go in the car; it's going to get the secondaries bridged and expanded, and 1" or so PPorts put in it pretty low down in the housing, for a lot more overlap. Scratch building an intake manifold for it with ball valves to shut off both the the 5-6 ports and the PPorts at varying RPMs, by solenoids. So no stupid vacuum lines or port actuation sleeves with all sorts of stuff in the air stream. Exhaust ports similarily big; I'm practicing porting on some of the *MANY* dead 12A housings we have sitting around and I'm getting the hang of making PPorts how I want them. EFI is... well, that's going to depend. I'd like to get ahold of a Microtech, but most off the rack EFI units would take a bit of fiddling to get the secondary set of ports (bridged 5th and 6th ports) and the tertiary ports (the pports; comparatively *LITTLE* pports mind ye) to actuate how I want.

You may be right that I shouldn't need to go any bigger brakes than the -SE ones, but well... I prefer to lean towards overkill. I want to get the suspension and rear end and everything built up to handle the power of the 13B from hell now because... well, it's honestly going to be a little bit until the 13B's done due to monetary constraints. And there's a lot else to do; fabricating or buying a tri-link and panhard bar, converting to rack and pinion, etc.

I'm looking at ending up with something that's brutally over-engineered for street use. I'm perhaps insane by normal standards, but hey... if it works it will be hellaciously cool, ne? Maybe I should just wait and see how long the stock rear end lasts; it's not like we don't have spares sitting around, and if I do horribly wreck it, I've got a friend who I can acquire a Ford 8.8 off of for not too much.

diabolical1

iTrader: (3)

Well, I feel more comfortable about you and your plans now that you've filled in some of the blanks. I don't know Rice Racing, but from what I've heard here on the forum, aligning yourself with him seems to be a great move in terms of tech and fabrication ideas. You seem to have the right approach, which is RESEARCH, as opposed to "doing-what-I-heard-is-cool" and that was why I was a bit concerned ... that's all!

Hey, if you can fund the brakes, I totally agree with the overkill concept. That's my philosophy on brakes ... you can never have TOO much!

On a final note, just want to say Good Luck with it all and if you remember, keep me posted with your progress.

1

Kenku

Heh heh heh... thanks. Well, I'm working on a degree in Mechanical Engineering (automotive isn't offered per se, but I'm an SAE member and that's what I'm learning for) and I'm tinkering with some mathematical models for rotary performance too... which... ah... I think I might need quite a few more years to get *those* off the ground. But just saying this for background.

I can understand how I can come off sounding kind of... absurd sometimes. Most people saying they want to put together a 300-ish HP NA engine for street use would be looked at as loons. I've just been sort of keeping quiet for the most part until I have something concrete to show. And so far... I don't.

Money's a bigass problem though. I mean, I might end up making a Megasquirt EFI system for the 13B (which would be nice in some ways because I could make it work the port solenoids). I'm almost definitely going to get a custom header worked up, but for reasons of *cost*... because I can buy the tube and have some friends help me fab it for a lot less than a Racing Beat header. Well, okay, partly because of cost... some improvements to be made to the RB design in terms of performance...

We'll see. I'll damn well make the thing one way or another, even if I have to make stupidly large amounts of stuff from scratch. I'm a bored college student living out in the middle of nowhere; there's nothing for me to do but work on cars.