moonless

Well I started working on my dads fb and found that it's entire wireing harness was trash. I'd been collecting s5 t2 parts to swap into my vert but am toying with the idea of swaping it into the fb instead. I know a few out there have put t2 motors into there fb before And I got a few questions?

1. what will the fb rear diff stand up to hp wise.?

2. does any body make a new front subframe to allow a direct fit? save me some of the trouble. If not I'm planing on makeing the new sub frame to accomadate the fc front suspesion, and wile rebuilding the rear diff moddify the axle for the fc 5 lug pattern.

3. How wide of a rear tire will fit the rear wheel wells before more then just rolling the fenders will sufice? ( I'd like to fit atleast a 225 out back)

well think that has it for now I know more will start popping up once I start getting into this but first got to source a fc s5 complete wireing harness

brandon davis

iTrader: (3)

Its easier to swap the front cover from any 85 and earlier 12 or 13b motor but you will need and SE oil pan.

The read end should take about 300hp i believe ive read.

the width of your rear tire depends on the wheel offset when you start going real wide.

do a search as all of this info is better detailed elswhere

Hit Redline

iTrader: (2)

1. I have a stock GSL-SE rear end with over 300hp and have about 1500 miles and no issues.

2. Already answered.

3. I run 2 different sets out back on a 15 x 7 45 offset wheels. 205 50 and 225 50 drag radials. No rubbing and I have a sub box in the back as well.

vipernicus42

iTrader: (4)

... what's the "different take" part?

The easiest way as brandon said is to swap the front cover off a 12a or a GSL-SE 13b so that your TII can bolt up to the stock front FB front mount. If your FB started life with a 12a in it you'll need the adapter from RacingBeat.

Swapping creates a slight issue for the OMP if you use an S5 because it's an electric OMP that the ECU needs to see in order to not completely gimp your engine. Most people just take the stock Electric OMP and ziptie it out of the way, still wired to the harness so the ECU won't complain and rig up a GSL-SE OMP to actually supply the oil or go premix. You also have to swap the oil pan because the stock TII oil pan does not have the spot for the stock FB steering rack to fit underneath. This has to come from a GSL-SE because the 12a oil pan is not the right size for a 13b.

Hjowever, with the new ReSpeed steering conversion it's definitely more possible than ever before to create side mount brackets that would let you bolt an S5 TII engine in with its stock mounts. While the kit does come with a brace bar that goes where the stock steering goes, it seems like you could remove it in light of the fact that the FC side mounts themselves would have a similar bracing effect. Nobody has done this yet but I'd love to see it done.

Swapping suspension bits from FCs into FBs has proven to be very problematic because the cars are so incredibly different. Big Brake upgrades using TII 4-pot calipers and larger rotors are possible (ReSpeed makes those kits) though you have to get different wheels and appropriate spacers to make it work.

The FB rear diff will take quite a bit of power, enough for a stock or mildly modded S5 TII for sure. Miata guys who autocross actually source our LSD diffs (which I find funny since we often source their torsen diffs) because they're strong and if you can find them they're cheaper than the Miata LSD or Torsen diffs are. I know they usually don't have much more power than we do, but I figured it was worth mentioning since some of the miata guys I know are putting down some pretty serious power and beating on their diffs on the track with R-compound tires.

That's all I can think of for now, if you've got more questions keep 'em coming.

Jon

moonless

well thanks for the info hit redline.

Ok the different take is the car will end up being a fb in apperance only by the time i'm done I don't need to know mundane details unless I ask about something. I'm not a newbie to the rotary or rx7 I've been messing with them since well before i got on the forum. I've owned more then I can remmber chris and elaine at banzai seem to poke fun at me about it every time I see them??? I've already got a roller with a entire fc front but I don't like how it turned out sits to high in front. since that time my dad has built his on full machine and welding shop so know I have the tools I wished I had then. I've just been waiting for a reason to build a fb like this.

brandon davis

iTrader: (3)

Then fab up some mounting brackets to drop the s5 motor in the fb chassis since you got all the tools then you dont have to worry about any of the s5 OMP crap.

vipernicus42

iTrader: (4)

By the time you're done what?

Dude you should proofread your posts. That sentance doesn't make any sense.

I wasn't trying to be condescending or anything. I don't know you so I don't know how much or how little you know. I was trying to provide information I thought you could use. In the future I'll just not volunteer any information, or even bother replying to your posts then.

Good luck on the project and whatever the "twist" is that gives this a different take. So far it seems like an FB with a TII motor, big brake upgrade and suspension. Not that different, unless you're planning to cut out the rear deck, bins and floor and weld in the entire IRS setup, now *that* would be different. I think I've only heard of that being done once.

Jon

djessence

+1 Jon,

Maybe the OP could elaborate on how this is different from the many other TII swaps that have been done so we can appreciate it a bit more vs saying oh, this guy thinks hes gonna be super different by..oh, putting a TII, not even an REW or anything *SUPER* different in it.

And "the mundane details" that were provided pretty much applied directly to your question and will probably help out others that read this as well.

But to be mildly helpful and not just post whoring.....:

So 1. The GSL diff has been said to withstand high horsepower better than a GSLSE diff, so depends on what yr/model of FB you have. Is it even a model with the large axles? As stated, guys are running 300hp with it, but i mean it depends on how you drive to an extent as well.

2. no. Adapters for front mount by RB, and another maybe atkins of Mazdatrix. RE-speed makes a crossmember you can mount a 13b or 12a in it.

Keeble

iTrader: (3)

there is a post i think in the archives on how to swap in FC front subframe and suspension, the only real mod i think you have to do is drill some holes.
that would probably help

moonless

sorry I had just woke up earlier I will agree my spelling and grammer was pretty bad.

OK to elaborate on the build plan.

1. The motor s5 t2 I want to build my own sub frame to mount it with factory mounts. I like this idea better since it doesn't use the cast front cover afraid of that cracking. This sorta goes along with the motor and is partly why I'm even considering this much work. useing the entire wire harness from a s5 dash chassis engine every thing. the hardest part of the entire build is going to be tracking through the wireing to make it work with the fb dash. On the cooling side I'm wanting to run dual oil coolers and a v mount set up.

Ok so that should give you a good idea of the under the hood plans,and that I'm keeping a pretty fairly stock interior lay out.

2. The drive line I got a rx8 six speed given to me needs from a freind for changing his out. needs rebuilt I figure I'll send it to liberty transmissions in MI. they got a good reputation for building performance transmissions. I got a 84 gsl I plan on useing the rear end from since I want the disc brakes. While it's out I plan to rebuild and swap in a 4.44 final ratio from RB. as well as weld up the 4 lug pattern and remachine for 5 lug pattern and build any bracketing to use fc brakes

3. front suspension/steering I'm still working this out I need to get some mesurements. I know the fb and fc both use the same outer front wheel bearing,but different inner's. I have one of two plans make a new lower control arm and use the fc spindle. Find out if I can machine something to get the fc wheel hub to work on the fb spindle. If I end up going the fc route I'll have to machine the top of the shock as stated earlier my last attempt set the front higher then I liked 5" from the bottom of the front lip to the ground. after dropping the car 3" and the shocks were bottomed out. now I can fix that problem. The steering I'll be converting to the fc rack and pinnion.

OK so some of it isn't totaly different I also do know of the 1 fb mentioned earlier that was fully converted to fc suspension. That was done by one of the guys at speed machine performance I talked to them when I was doing my first attempt. (Then got side tracked by a mint t2) The part I havn't really ever seen or heard about being done is upgradeing to the newer electronics. Part of why I like the idea of useing the fc harness. Is it will allow for use of A power fc to tune the motor later down the road.

Hope this helped to clarify the blue print thats been going through development in my head since last weekend.

moonless

keeble yeah I did it that way last time turned out not so good

djessence

There we go.....

I believe the user "Kim" had the write up that Keeble mentioned about the fc front clip

Re-Speed.com

iTrader: (3)

A few things I will comment on:

1) I always hear this. Have NEVER seen a front cover crack or have ANY problems at all.

2) GSL axles do not have enough meat on them to drill the 5x4.5" lug pattern. The rear ratio chosen is directly related to the amount of HP the rear end can take. 3.9 ratios have more meat on the base of the teeth than a 4:44



-billy

moonless

billy thanks for the 411 on the front cover I've heard they can't handle the power multiple times. I am going to give the respeed front sub frame a look.

On the rear end if I can't find a safe reliable way to mod it. I guess best option would be fitting a ford 9" or something simalar.

I remmber seeing a place that did v8 swap into 1st gens afew years back called them pythons or something I think they sold beefed up rear ends anyone know if they are still around??

moonless

Billy just got done looking at respeeds web site I hadn't search fb stuff in like 5 years. They seem to have just what I need to get the car to a 5 lug roller. I liked the front cross member,but will probably still make that myself since I'd still end up haveing to make engine mount locations. As well as it'll be cheaper I got more then just this project that will be consuming some green.

Re-Speed.com

iTrader: (3)

No problem. Let me know if you have any questions or need anything. Did you check out the moser axles we offer?

-billy

nick812

There has been been people running front cover mounts on 20B's without issues. Ducktape did over 400+ without an issue. Now I do belive he said the brace did have a little bend in it.

PercentSevenC

Yeah... I've never heard of a front cover mount having problems. The 20B guys use them all the time. Dual oil coolers? V-mount? Sounds like you're making things way more difficult than they need to be. And RX-8 6-speeds suck, I hope you're planning on having it strengthened.

moonless

Yeah, thanks billy I've rethought the suspension. I'm going to stick with the 1gen use your spindle, and front brake upgrade. As well as the moser axles and rear brake up grade. Use the bbs wheels off my vert. Won't be able to fit as wide a tire as I'd like but will look nice.

Presentsevenc: Yeah the freind that gave me the rx8 tranny has the greddy turbo kit And dyno'd the car at 320 to the rear wheels. We put three tranny's in it. The last one I jacked the car up so high on the fill side he thought the car might tip over. I also made him buy some royal purple that time and I mixed in some motorkote for good measure. That ones been holding up fine.
The dual oil coolers and v mount are more of a trial run to just see how I like the set up. My t2 has major cooling issues at the track,but I can't bring myself to tear her apart for to long without some other toy to play with on the weekend.

Hopefully I'll get the rest of the car stripped down by the end of the month and will be able to start building in october I"ll post pic's once I get rolling.