1990 Rx-7 VERT Auto4spd-> 6 speed MT.
 

Firstly to answer a few questions before they're asked...

Uses the original AUTO driveshaft. no mods
engine moved backwards about 3 inchs, and shifter hole cut forwarsd an inch. original rx8 shifter doesn't hit radio, will be going short shifter.
rx8 tranny.
custom mounts X 3
probably gonna have to customize the intake/exhaust for the engine moving, maybe radiator hoses also.
to be drove by this time next week.

pics!
https://www.rx7club.com/attachment.p...1&d=1337002443
SOO CLOSE, This was before cutting the shifter hole.

https://www.rx7club.com/attachment.p...1&d=1337002443
https://www.rx7club.com/attachment.p...1&d=1337002443
https://www.rx7club.com/attachment.p...1&d=1337002443https://www.rx7club.com/attachment.p...1&d=1337002443

Tans mount is next. ^

Interesting...

Yes, interesting. Would a custom driveshaft have eliminated the need for relocating the engine at all? Or was there just no room for the transmission?

Looks like you could just drill a couple holes in the trans mount bracket and still use the stock body mouts.

NO. the first picture is of the engine moved back 4 inchs. with the engine still in the stock location, the shifter would be under the radio. This is in the FAQ! c'mon man. :lol:

:blush: Yeah, I read it, but it didn't quite compute right away. :icon_tup:

the 5 speed in the NA vert is such a sweet set up, you can drive around in 3rd gear all day long on the highway having a blast

whats the thinking behind this 6 speed swap?

hmm. my auto was. .........

89-92 Non-Turbo w/o LSD

The 6 speed is...
if A is < B than C is > B

I'll soon find out if i can put that fc 3rd gear in the rx8 4th. with/without major refab.

Hmm,if that trans cross member is in the place you want it to be,then I have a suggestion.
Cut the middle of the Cross member out a bit,the trans mounting bolts will drop through,then get a plate with the 2 holes (I think I see 2 mounting studs on trans?),put the plate up to the member,with bolts through the 2 holes, tack,done.
That gives you Stock mounting and also uses the studs on the trans.( I think!!!)

Nice job. I like good fabrication and curiosity such as this, but there are a few flaws in your design. These are mostly nitpicking items, but some attention to these would make a better finished product overall.

Transmission Crossmember: Would be simpler to just fabricate a new one. Another item you may wish to consider acquiring are the FC's Manual Transmission crossmember mounting ears, since AT to MT conversions encounter a similar problem as well. On my 20B FC, the MT ears are bolted to the car's unmodified sheetmetal using 8 aircraft bolts each in the same location that a factory MT car would have them. Between the two pairs of mounting ears, you should be able to find a suitable location for the new transmission crossmember. If you're feeling ambitious, use both pairs and it will be much stronger.

Crossmember doesn't have to be anything too fancy, just some C-channel cut & welded in a "stretched V" shape similar to the original ones

Relocated Engine Mounts: These look fine, but there may be a simpler solution to the shifter location than reworking the engine mounts (and everything else related to them)

Shifter: The FAQ states the FE's shifter is about 4" forward of the FC's shifter hole when everything is mounted in the stock locations. Wouldn't it be simpler to just modify the shifter housing instead of reworking everything else? If it is cast aluminum like its predecessors, it can be cut in half on a bandsaw (rearward of the bolt holes), then a 4" extension can be fabricated and TIG welded in to line everything up in the stock FC's shifter hole. Repeat for the shifter rods using suitable steel bar. I maye be wrong about this, but it should work like stock. Defined Autoworks has played around with shifter relocation before on Christopher W's 20B GTUS to get the shifter to line up correctly when the 20B engine & T2 transmission have been relocated further back. This is the opposite direction of what I suggested doing, but it is in the ballpark of what would need to be done. Might try PMing GTORX7. to see what they think about it.

Speedometer: How are you planning on linking the FE Transmission to the FC's speedometer? I do not know if the FC's speedometer drive gear will bolt onto the FE Transmission in place of its Speedo Sender, but using the FC's speedo gear may be the simplest solution.

Overall, I like that you're thinking outside the box with this project. It has a lot of potential, just needs some refining here & there. With some different gear ratios (Hint: Mazdatrix), this could be downright brilliant.

Did the RX-8 trans input shaft slide right into the 13B or did it require any machining (like what has to be done when fitting a Miata gears in an FC trans housing)? Do the bell housing bolts on the RX-8 trans mount right up to the 13B?

Are you saying you're trying to mix and match gears from the two transmissions? Any luck with this? I was looking at gearing for my racecar and realized that an RX-8 transmission would be perfect if I could put the RX-8 3rd in the 2nd gear spot, use 3rd from the FC, and 4th and 5th from the RX-8...but I somehow doubt this could be done.

Any updates on your install would be greatly appreciated. I have a feeling I'll be dropping this transmission in to my FC racecar this winter.

The rx8 clutch is the exact same as the 88 turbo II, i use them when doin rx8 clutch jobs to save about 200 bucks.
The rear iron bolts to the rx8 trans perfect, so does the rx8 starter. no mods.

The purpose of redoing the engine mounts was to reuse the auto driveshaft, with no other mods.
i've yet to decide what to do about the speedo. i'd actually forgotten.
but thats another day. UPDATE :)

https://www.rx7club.com/attachment.p...1&d=1349735685
https://www.rx7club.com/attachment.p...1&d=1349735685
https://www.rx7club.com/attachment.p...1&d=1349735685
https://www.rx7club.com/attachment.p...1&d=1349735685
https://www.rx7club.com/attachment.p...1&d=1349735685

How low can you go?

https://www.rx7club.com/attachment.p...1&d=1349736067
https://www.rx7club.com/attachment.p...1&d=1349736067
https://www.rx7club.com/attachment.p...1&d=1349736067

So... the intake manifold had fitment "issues" ... and here is revision two, closer to what i wanted, but maybe a little too low, at least this one will see alittle bit of the road.

These are really just TACK welds.. there are ugly spots that need to be fixed, and about 6 four inch beads to be laid.

about 3 inches down, and 2 inches back. yes I think the oil pan would scrape as is... probably just gonna lower the bitch on a stack of wood. :D


as far the the Are you saying you're trying to mix and match gears from the two transmissions? Any luck with this? I was looking at gearing for my racecar and realized that an RX-8 transmission would be perfect if I could put the RX-8 3rd in the 2nd gear spot, use 3rd from the FC, and 4th and 5th from the RX-8...but I somehow doubt this could be done.

It's been while since i had an fc trans part, and havent had an rx8 one apart yet, but i think i'm ready for that kinda of challange, the best solution maybe to use the 09 rx8 trans, as it has the same 1-3, but a 1.4 4th, and a lower 6th. there are threads on the rx8 forum, that have more info.

https://www.rx7club.com/attachment.p...1&d=1350007669
https://www.rx7club.com/attachment.p...1&d=1350007669
https://www.rx7club.com/attachment.p...1&d=1350007669
https://www.rx7club.com/attachment.p...1&d=1350007669

So there is your trans mounts, well mostly, after modding the verts subframe sub-brace, everything clears, time to see about up top, before solid welding the subframe up. Yeehaw.


I'm going to make a prediction that i will be cutting and rewelding the passanger side mount, to make the exhaust clear, and also make the trans flat and flush with the mounts as is.

Would it been easier to make a shifter extension and longer driveshaft?

too much work for another glass tranny.

ha, for an n/a vert, it will be fine, and it would have cost more to get an aftermarket driveshaft,

[IMG]Would it been easier to make a shifter extension and longer driveshaft?[/IMG]
why don't you do it and let us know.

https://sphotos-b.xx.fbcdn.net/hphot...61837102_n.jpg
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so i did remake the passanger engine mount, and then finished the tranny mount.
cost? tranny was 500 shipped, clutch 130, slave/master lines another 50, tranny mounts $40, and all the metal and gas prolly another 100-200.

I can't say i did this for cost, or so that i could own a 6 speed vert. I did this to try out my new tig, and practice making stuff fit. i don't see how anyone would rather sit and watch tv, then to cut and melt metal together to create something. I do not own a tv, although i will watch southpark when on dvd.

Mazdaspeed miata uses the same transmission, but the shifter sits further back than the rx8 shifter I'm sure you could swap the tails

Or swap the bell housings and do similar mods to using a 5 spd miata trans in an fc

Personally I'd do a final drive before I put a 6 speed in

well, for reference the 8's spit out these trannies about as often as n/a FCs do. yea i realize they have about 50 more whp and are heavier so i'd say they are only marginally more sturdy.

the auto 4 speed was blown so a trans swap was necessary. why not step up?

if i did this over again, i would concider a custom drive shaft to move the engine back another 2 inches.

lowering= lower center of gravity, better polar moment of inertia.
moving engine/tranny rearwards= better weight distribution.
i feel like some of you guys miss the whole point of this.
1. test my skills.
2. prove that it can be done.
3. get my vert back on the road, converted to manual.
I certainly wasn't looking for the easy way out, yet the money spent wasn't very much. just a good bit of time.

Need to re-weld that, it's already cracking. Less wobble / trying to walk the cup and more filler.

My question is, is first gear to tall? To short? Will 6th gear be to Low? How do you get the correct Gearing so it will be Enjoyable?