Rx8 trans in rx7 fc3s
 

They said carbs suck but I did it
They said turbos and carbs don't mix but I've done it.
They said the rx8 trans won't work in rx7 but I'm doing it :nod:

This is what I've done so far.

Two questions:
What was involved in moving the shifter?
What are you doing for a speedometer cable?

The shifter plate is 1/8" steel with bracing and still uses 2 of the factory holes so the shifter sits 1/2" more forward than stock. The shift rod is extended out the back of the casing and has a dust cover like a shift boot. It was too tight to get a ring seal in place and I will improve the design of the next one.


I will probably go HUD heads up display speedo. I want the factory one to work and I'm looking for options. I do have some ideas on how to do this but need to do more research.

there is some hot rod thing that will take an ABS wheel speed sensor, and then drive a cable...

Use the electronic speed sensor from the RX-8 and feed the signal to either a Miata or Integra speedo.
The Integra is a pretty simple swap into the FC cluster, not sure about the Miata.

aint got none! the Rx8 uses the ABS sensor to drive the speedo, so there is nothing in the trans, and no provision for anything

BUT

the hotrodders have this problem with something, so you can buy something that will drive a mechanical speedo from whatever wheel speed sensor you have.

Just out of curiosity, why did you go with the series 1 transmission over the series 2 transmission?

Here it is. It's $340!

Cable X...Electronic Speed Signal to Mechanical Speedometer Adapter

Or just use a 50-75 dollar tom tom and then it uses GPS for speedometer


probably 30 bucks for the small guys on craiglist.

and now you have added navigation!



I picked up an rx8 trans as well, that swap is in the works but not until I finish the new engine. New powerplant is going in all at once. However Its not really driven in on the street so I could care less about a spedo and there is no interior so egg shaping the shifter hole is no biggie :)

sub'd

BTW I run a mikuni carb as well, I understand where your coming from.

S1 or S2 transmission?

it's an upgrade over a n/a FC transmission but it's just too much of a headache to accomplish unless you track the car.

both S1 and S2 are weaker than the turbo transmissions, however the 6 speed with dual cone synchros shifts smooth as butter comparably.

The S2 transmission might be weaker than the turbo transmission, but they are definitely good for over 400hp.

I only found 1 s2 trans and it was more than twice what I paid. I wasn't sure if this would be successful so I bought the s1. If when I break it I'll try the s2. After installing the mustang 17"wheels on my car 2nd gear was almost as tall as third in my rx8, that was my insperation.

careful with launches, i have about a 6" section of tail shaft(don't overthink it...) from an S1 as proof that they cannot be abused.

I have a friend, who gets 12.0@116 with the smooth 5spees and open diff. He did break 3rd once and a tll trans rear are on the way. I don't race very often but don't want it to break either.

When I go turbo I know my peak hp will drop and I will have to shift earlier. I'm going to combat this with a gizzmo ibcr boost controler that controls via rpm. I'm hoping this will be more gentle on the trans and give a higher peak hp as I can over boost at higher rpm.

RotaryEvolution if you have done this before please comment. Thanks.

Ditto. Some deals are hard to pass up, sure I would prefer an S2 but time/money/availability. Also the 2KW starter with the rx8 is a nice feature, the FC starter motor is only 1.2KW for manual trans (auto trans got 2KW)

My roommates STX rx8 is very competitive and experiences lots of launches without issues, however he is plagued with a bit of the 2nd gear syncro issues that is common with them. I am fortunate that I launch on dirt so I'm not concerned as much. it depends on your track/application.

Everyone said the NA trans is weak (and it is) but it still held up to some serrious rallycross abuse, it got tired but didn't effectively break. However having held both a t2 and an S1 trans the S1 is lighter.

Granted I also make less power than a stock rx8 and weigh less than one too.


Ghost: How do you plan to mount it? I am aiming to utilize the stock FC location with some sort of solid bracket, I thought about chopping up part of the PPF to make a mount easier. I have also been told to use this slave clyinder since the rx8 one hits the oil pedestal on the earlier 13bs.
Oreileys part# cs2162

observe:
http://picoolio.net/images/2014/03/06/photo20112.jpg

I think the trans mount will be easy. Mine was originally a auto so the mount is further back an appears to line up. I think i can make a good one by modding the factory mount. I'll be installing it in a couple weeks, I just have a lot going on right now.
I read somewhere that the eclipse 2005 slave works so I bought one $15. To use the factory one looks like I would have to use a 90 on the hydrolic line.

You can't physically use the rx8 slave cyl in our cars, see how it sticks past the bell housing? but either way post your part# and where you got it for reference. I'm not sure exactly what car the slave is that I posted but I was told some honda.

I watched the video and you said that you were going to use the auto driveshaft, does that have the t2 output spline or NA spline?

the t2 drivehsaft slips right onto the rx8 trans, same diameter shaft and spline count but the driveshaft length is the same. Right now I have a rx8 trans output yoke and the N/A M/T driveshaft. I figure lop off the middle and get a tube to fix that issue at a driveshaft shop to fix the length issue.

snap some pics of your factory mount when you fab it up before/after I'm curious to see.

I believe the body has the same holes but the trans rear mount itself is different.

the Rx8 has a power plant frame, so there are just 2 big studs where the trans mount would be. you obviously need to fab something, but at least there is a big stud kind of where it needs to be

correct, but who says you cant cut off part of that PPF to simplify mount fabrication?

http://www.rotaryresurrection.com/kl...p/DSCF1548.JPG

Here are the auto and manual trans rx8 driveshafts and PPFs, it looks just like stamped steel so I would just cut about a foot back from where it mounts on the trans to be able to weld flat steel add bacon then multiply by beer divided by welder and it viola!

I really haven't thoroughly thought this part out yet if you haven't noticed. I haven't decided exactly how I will achieve this part yet but this was a thought of mine.

at least the bell housing bolts up!

lol! yeah basically add bacon divide by beer...

i haven't tried to bolt one of these in an FC, but i was picturing the PPF stud just going through the center hole on the FC mount...

super now sells an FD trans into an FC car bracket, its simple

I'm going to focus on the 2 mounting bolts on the bottom of the trans and maybe a brace to keep it from rocking.

As for the drive shaft the turbo ll is 7/8" too long but I will measure it again once its in the car. The automatic drive shaft is 2" shoter than the turbo ll shaft so there will be 1" of exposed yoke no big deal and it has the Tll yoke n/a rear.
My turbo ll shaft and rx8 shaft line up nearly perfect with the N/A rear so with the right size bolts I think it will work. It looks like it will bolt up with factory bolts or maybe a size smaller. If I try a smaller bolt ill use something strong and a drive shaft loop.

When I recently pulled my engine out for some R&D on a new engine I put the t2 trans next to the rx8 trans to get an idea roughly what I am working with:

http://picoolio.net/images/2014/05/0...0412144455.jpg
http://picoolio.net/images/2014/05/0...0412144508.jpg
http://picoolio.net/images/2014/05/0...0412144513.jpg

For some reason it looks like such a stretch in your pics. Honestly it's not very hard. Hardest part is sealing the hole in the tail housing. I also had to cut and shave the shifter adapter to have safe clearence from the drive shaft yoke and my drive shaft does not have the yoke shield.

What I should have done was put them bellhousing down and lined them up. I'm curious to see how you did your shifter adapter so its not as far forward. What is this hole in the tail housing you speak of?

The shifter uses two of the factory mounting point. This puts the shifter .5" forward for FC and .5" back for FB. After I made my block off plate/brace I had to extend the shift rod out the back of the trans tail housing, this is the hole that's hard to seal. I tried to make the rod using pipe as a collar but nothing fit so i had to have it made from a solid piece. The hole is where it exits the rod exits the trans to connect to the shifter. I have a piece bolted to it like a shift boot for the rod. It's no great but should work. Once I know everything works ill invest more money/time into a better design. For now I'm very happy with what I've done.

I would really like to see more of what you're talking about here. Can you get some more pics?

Does it look at all like you could swap tail shaft housings? Then maybe use the shifter tower for the 8 on the tail housing of the 7 (for the reverse lockout)?

Nope, not at all. Two different transmission suppliers and the size differences of the case and differences in shifting mechanisms prevent it.

The tail housing also has the stop pin for the shift rod.
All I did was extend the shift rod 8cm and make block off plate/brace.

I've been busy but will keep everyone posted.

i guess i can stop telling people on the street i got the only 6 speed rx8 transmission'd rx7... in the usa... now i have to say alabama...

put some miles on my now... still no speedo :P
https://www.rx7club.com/attachments/...t-sam_0204-jpg

mounts look good how do you like it over the 5 speed?
turbo or n/a and is that car originally auto?

This is 2nd gear in my car, it was originally auto trans and after installing 17" rims the speedo is only 3mph off at 75mph.
the gearing is killing this car its a holley carbed s4 6 port with 95psi per face. 1st 43mph 2nd 84ish 3rd 120something. still licks 14's @94 mph yeah its a beater 75mph 1/8mile if I had the stock tires for it I'm sure it would be half a second faster. It spends a lot of time out of the power band when I launch and shift. After this its turbo time and then EFI. I already have everything I need but time.


Just plasti dipped my rx8 gt came out real nice
Konig staggard rims
tein coil overs
ls2 coils
slotted brakes
4.1 rear gears no more granny gear its a street car not a race car.

the car is currently the stock s5 motor, building up a semi peri for it to be put in later this summer.

when i used to drive a 5 speed 7,going WOT to redline in 1st and 2nd, i would shift 1st 2nd then 5th.
now with a 6 speed i usually shift 1st 2st 6th, but if i get on the interstate i use 3rd to get to 80 before going to 6th

the 3rd in the rx8 is a tad higher then the 2nd in the fc.

you're basically replacing 1-3 in the fc with 1-4 of the rx8. 4 and 5th are both 1:1.

Definitely not.... I've been rolling mine around for 3 years now ;) And pushing 400rwhp through it.....

My question for you though is, keeping the stock RX8 tailshaft, how did you go about moving the shifter back the 3-3.5"?

Cheers

I should of taken more pics. I took the tail shaft off and had a shift rod extension made. I drilled a hole in the back of the housing where the shaft exits. I made a boot to keep oil in and dirt out, honestly this was the hard part and I'm not 100% happy with the boot but I do have plans to improve the next one I build.

The brace is 1/8" steel plate and I will know this weekend if there are any clearance issues. I used the back factory shifter holes for the front of the shifter this moves 8cm or 3.149" any further back and you will hit the drive shaft. There isn't much room to box it in so I left the bottom of the shifter exposed. If it needs to be cleaned or greased I can easily do this from inside the car.

thats the funny thing with mine, i could pull my trans and put it back into an rx8 if i wanted.. the way i did it was i remade my engine mounts, and trans mounts, so move the engine back 3 inch and down 2 inch, lower polar moment of inertia, the stick sits about 1 inch forward of the stock location, but it clears the radio because of the short throw.. also i have richard pauls short shifter(axial flow).

also mine is in a vert, so it already has a lower center of gravity, i can wait to track it.. it gets me a lot of eyeballs from the popo for taking corners/turn so fast..

I certainly agree with the more picture thing. Sholda, wouda, couda...

This explanation does shed more light though. Thank you

Ahh the beauty of having a gutted race car, I'm just going to make the stock hole more egg shapped.

who has the gutted race car? i'm just missing the shifter surround. doesnt quite count as gutted. also i said something about taking it to the track, more often then not it just goes to the beach...

Trans is in and drive shaft did not need to be cut. The factory Tll shaft fit. The shifter is in a perfect position and no other mods needed. I'll post some pics when I have time.

Interesting. How did they build the shift rod extension and did they keep the 3 grooves that work with the detent ball and spring to keep the tranny in gear?

I'm wondering if the increase in height is going to have a negative impact on the extension and retraction of the shift rod and there's also the movement between the shift rods, moving from side to side has an impact on the rotation and overall angle. I'm hoping there is more movement allowed in the shifter to allow for the extra height worked in there with the 1/8" plate.

Really? Wtf are you running for an engine? It's definitely not the single turbo 13B-RE that I've got. There I no way possible to move that engine back at all. From memory I don't think you'd be able to get the n/a engine back quite the 3-3.5"... I guess an MSP would fit just fine.

That's a lot of material to cut away. I don't think you'd be able to use the stock dash, but maybe?

Awesome! Especially about the driveshaft, that make me happy because the custom AL one that I had made a few years ago was too short and vibrated a little because of incomplete engagement with the output shaft and bushing.

I'm going to try basically what you did, but without a plate on top, going to rebuild the shifter box where I want it but keeping the shiftrod bushing in the tailshaft right before the box, and I'll extend the stock shiftrod somehow to keep the grooves and the detent ball in the tailshaft housing

How did you solve the slave cylinder issue?

i'm running the stock s5 n/a engine? as stated. glad you've basicly called bs on what i've already documented if you simply follow the link in my sig.. you can actually see my mounts and the progress of making them. they look like shit. you can also see were i couldn't get a heater hose on the heat core for the intake manifold being slammed up next to it( although it's re routed and installed now).

Me.

AngryPerson:

I don't have a stock dash anymore so I wouldn't know either :)

I used 1/8" plate to keep within the tolerance of the shifter geometry. You have to brace it from the side so its ridged.

The slave cylinder is still a challenge. I bought a 2005 eclipse slave but the mounting taps need to be at a angle for the rx8. I will have to modify this slave to sit at the proper angle.

Damn dude.... don't get your panties all in a twist because you now know you're not the first to do this swap :lol:

Is hardly calling bs.... I stepped away from the power limited n/a's like 8 years ago.... so it's a little hard to remember these things :rofl:

Gotcha.... because racecar

My solution is going to involve a bandsaw and a TIG welder... accomplishing the same thing.....

I took an old n/a slave that I found, cut the ears off and rewelded them on to match the 8's bolt pattern..... has been fine for over 4 years... 40-50k miles and I have an exedy twin disc clutch....

I'm going to try the 2005 eclipse slave and I'm pretty sure ill have to take it apart and re weld the taps to match the rx8

i used a kia sportage slave, although theres a referance to using a honda slave that looks even better then the kia one, the kia one is at an angle just slightly. i'm gonna try the honda one and if it's not damn close i'm going to reweld the stock one like that angry guy.

whats the issue with the slave?

the stock rx8 slave hits the 13b oil filter.