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have you seen a turbo-II manual S4 transmission? Mounting points look very similar (2 bolt holes at the bottom of the transmission). If that fits, all you would have to do would be to cut the shifter shaft short and move the shifter housing forward.
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you would have to do more than that, for starters the FC used a chassis trans mount not a PPF and the list goes on from there ....
just had a 5 spd RX8 trans offered to me, thinkng of buying it to hang out with the crowd of 6 speed boxes I have stacked up |
Ok, I have a 5 speed coming. I will probably use it as is until it fails and then do the FD swap...this thread was great. Thanks Dznutzuk.
Cheers! |
Whats the signs of a stuffed box?
Ever since my third year at Santa Pod my 3rd to 4th gear change crunches. First second and third fine though. 6 speed manual tranny |
I'd say you need new synchronizers...
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Originally Posted by dznutzuk
(Post 4130492)
Hey everyone, I started re-building a new transmission today that will solve many people's problems. This transmission is actually and RX7 FD unit, although it's a 5-speed, I think the ratios are much better than the 6speed. This is actually kind of a info-DIY thread. The problems with the FD trans is that:
1.) the ppf frame has a slightly mounting point for 2 of the screws, you would have to alter the ppf. Forget about it... 2.) the clutch is inverted compared to ours, you would also need to alter the clutch line, new slave cylinder unit. No need... 3.) the shifter is in the wrong location. No problem... Here in Europe we have a low power model with 192hp(basically your automatic version) to lower the cost. This version is offered in automatic and (only) a 5-speed manual. The 5-speed is the generic R15M-D which is also used in the RX7 FD. Now I'm not saying that it's the exact same gearbox, I don't know about the internals, and how strong they are. From what I know it's just the MX-5 equivalent, which is crap. So, I got a used damaged unit from the low power RX8 and switched over the parts. The outer casings(minus the bell housing and rear end) are the same, it's the same transmission layout. So the bell housing fits perfectly and has the clutch style that we need. The rear casing which houses the shifter also has the same location that we need and also the correct ppf mounts. Like I said, the is the perfect setup since those parts are from the RX8. I'm not 100% sure about this but, it can now use a FD short shifter upgrade or those el-cheapo versions that are found on ebay for like $40. |
Hi
Apologies for resurrecting an old thread, but I hope you good people can provide the info I need. I'm trying to learn about mazda transmissions, in order to work out a viable engine swap. I have a schematic showing the m15m-d and r15m-d gearboxes. Dimensionally and externally, they look very similar. Are they the same physical dimensions? If so, will a bellhousing from an M15m-d bolt straight on to a r15m-d gearbox? If yes, then do the M15... and the R15... use the same input shafts, in terms of length and no. of splines? I have a truck with a 2.5TD engine and a r15mx-d gearbox. I want to fit a petrol v6 - in South Africa, this was an option with (I believe) a m15mx-d gearbox. Before blowing money on parts, I'd like to know if the bellhousing would fit my gearbox, and if it would be the same input shafts for both variants. can anyone enlighten me? Thanks! |
Originally Posted by dznutzuk
(Post 4131309)
Back to the subject, I finished the trans today, and everything went great except for the shifter. I also had to use the main shifter rod from the 8's since it's a few inches shorter and I didn't want to cut anything. The problem with the short shifter is that the movement is restricted by the shifter housing, but nothing a little milling won't take care of. I'll try and finish that up tomorrow.
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Where do you live ?
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Originally Posted by haugi88
(Post 4849319)
could you uploade the pictures again please? i`m planing to do this swap in a few weeks.
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Sorry, I could view the pictures of your post. But now it's working. At least on the Mobil.
Br |
I think he's saying that the photos weren't working but they are now and that he's using his phone to view them rather than a computer.
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Hi dznutzuk, great post thanks.
Wondering - did you have any issues with speedo cable / ECU / DSC etc.? Does everything behave the same in that area? |
Fourrotor, rx8 doesn't have a speedo cable-it's measured by the abs sensors. No problems.
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Ah right, great - and all the DSC must be through the sensors also? I'm looking at putting a close ratio FD box in my 192 - so would be doing something similar to you I think? you didn't have to modify the propshaft? (which propshaft are you using?)
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Close ratio fd? If it's a stock fd transmission I suggest you DO NOT install it, your better off going with a 6 speed. Dsc has nothing to do with the transmission and I still use the stock rx8 prop shaft
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Just for the record because the information is becoming harder to find on teh intrawebz as time passes on, but the JDM 5MT has different 3rd &5th gear ratios than the EUDM 5MT transmission
JDM 5MT 1st - 3.483 2nd - 2.015 3rd - 1.391 4th - 1.000 5th - 0.806 EUDM 5MT 1st - 3.483 2nd - 2.015 3rd - 1.484 4th - 1.000 5th - 0.762 (S1 4.444), 0.719 (S2 4.777) these attachments are from a 2008 Mazda JDM sales brochure and a Mazda press kit for the British International Motor Show 2008 (BIMS08) https://cimg2.ibsrv.net/gimg/www.rx8...08b9cc805.jpeg https://cimg0.ibsrv.net/gimg/www.rx8...c5c480721.jpeg |
Hey, so the J version has that long ass 3rd gear which is a pain in the ass even on the fd and also a totally different 5th gear. Back then I had found that the euro 5th gear was .762, I have no idea though where I found that info. Nice Team
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3 Attachment(s)
I was just going to update it. Turns out the S1 & S2 UK 5MT had a different 5th gear ratio. They did update the R&P from 4.444 to 4.777 on the UK S2 5MT too though. That lowered the overall gearing and made it easier on the low power engine to accelerate.
the attachment above was for the UK S2 this one is for the UK S1: |
My 2003-4 JDM 5 speed has a longer 5th than the S1 6 speed (6th) so it can't be 0.806 . Would likely be 0.762 like the EDM model .... That's the ratio I found way back when I first fitted it but can't remember where I got that info from . https://www.rx8club.com/series-i-maj...4/#post4403025
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All I know is all the documentation and jp websites lists it as 0.806 for JDM. Maybe you got it from the UK version? Because there’s nothing from Mazda detailing any of these differences other than digging through the various official documentation and figuring it out.
this is from the original JDM RX8 press release in 2003: https://cimg8.ibsrv.net/gimg/www.rx8...f96ea8351.jpeg |
hmmmmm ...ok . It was very rare to see uk rx8s hereback then (a few around these days). Plus , this is the 3rd 5 speed I've had and they all had the same 5th gear ratio IE same rpm at our 100km/hr speed limit.
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So looking at the FD3 5MT (from RX7Club, can’t be sure of accuracy)
USDM 5th gear - 0.719 JDM 5th gear - 0.806 (16” wheels), 0.762 (17” wheels, Type-RZ) I couldn’t find any NZ or AU sales brochures, were those all JDM or AUDM? |
I presume the rx7s we got were mostly JDM as very few would have been purchased new here and that's were we have imported second hand Jap cars from for decades.
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I was referring to RX8s, just posted the RX7 5th gear info for reference since the RX8 bell, shifter, & tail housings readily swap over onto that same main case & internals. From what I see, all of the paired-gears are removable (not cast integral to either shaft) and should readily swap between them all. There may be some aftermarket gear-pairs available too I’d think. You also have options for aftermarket gearsets; PAR and Liberty are two I know of that are readily available. OS Giken supposedly, but a few RX7Club members have been on a wait list for almost 2 years now.
Ultimately the main case and even a stronger 3rd gear are still the weak points, but I know a 4-rotor that put 1000 hp/600 ft-lbs torque through a Par straight cut dog-ear gearset for quite a while before finally breaking the teeth off 3rd gear gear and cracking the case. Which you can get the PAR gearset with the wider straight cut gears and synchros for more civil street use. However, not cheap and you can probably do an aftermarket trans conversion for less, though then you have to adapt it to, or eliminate, the PDF. So there’s some work & cost in that part too. . |
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