New Miata Transmission Option

FlightService wrote: Quick, someone find a hooned E30 M3 and swap the S14 4 banger for a K24 hybrid.

I wouldn't go that far, but a healthy K24/K20 Frankenstein in a 318ti could be a real riot.

In reply to NickD:

400 hp in a E30????

I would Dr. Evil laugh that all day.

Could you also use the kit to put the BMW transmission in and then just not use the adapter kit and put like, I don't know, an S54 in the Miata?

What about Honda V6en, does this work with any of those?

In reply to pres589:

Pretty certain that the K-series and J-series do not have the same bellhousing pattern or such

In reply to NickD:

Yeah, these parts are going to open up the doors to some pretty interesting swaps. I do happen to have an S54 right here... too bad it's currently in an E46 M3 engine bay.

NickD wrote: I wouldn't go that far, but a healthy K24/K20 Frankenstein in a 318ti could be a real riot.

I thought about it for a second when I saw this. The S52 in my 318ti is starting to have issues. Then I remembered how much I like bottom end torque and how I'm planning to tow my challenge miata with it.

Back to dreaming of a Vortech

Sonofabitch,just bought a rebuilt miata 5 speed for mine and intend to go the ecotec route....now I'm having very bad thoughts for my wallet.

from what I have seen, and KMiata would know better than I, due to availability, reliability and junkyard costs, adaptors for Honda J and K series to VW/Audi/Porsche, BMW, Ford (Mustang SBF, Coyote, and Triton) and Chevy (any V8/RWD V6) transmissions doesn't seem to be a bad business to be in.

All the Honda boards (K20A.org, J32a.com, ect) say get a Supra trans for manuals, which is scarce and expensive. The K to TH400 seems popular with the drag racers too. KMiata seems to have a more-than-just-Miata opportunity here.

Personally, I would love a J series powered Boxster/996.

Ian F wrote: Neat idea. The potential bug for me is it trades one of the best shifters ever made for one of the worst.

I've never driven a 6 speed Miata but I've driven a bunch of 5 speeds and personally I wouldn't class it anywhere near one of the best. It's far too easy to get the wrong gear. Judging by the number of spec. Miatas I've seen spinning off the track from unplanned lower gear selection and the presence of add on fifth gear block out things I'm not alone.

This thread is so full of good ideas, and honestly, using this to put a honda engine in an E30 could be pretty entertaining...plus it is pretty easy to adapt the bmw RWD diffs to inappropriate vehicles, and there are a lot out there with mechanical LSDs. Something tells me an EG3 Honda, E30 rear suspension and diff, and longitudinal K24 with a BMW trans would be a riot. Or I could just get a 318ti, I suppose.

Regarding shift feel, you have to replace EVERYTHING on most old BMW shifters to get it to feel good. The T thing on the trans including shims and the little foam insert, the cup, and the shift lever itself because it is rubber filled and has a ball and a lower bushing that both wear. DSSR also is an improvement if you tend to shift forcefully. BMW synchros also seem to be sensitive to fluid type and temperature - if it's not running fresh Redline MTL (or synthetic ATF if you abide by the sticker), it's probably not going to shift very well.

APEowner wrote:

Ian F wrote: Neat idea. The potential bug for me is it trades one of the best shifters ever made for one of the worst.

I've never driven a 6 speed Miata but I've driven a bunch of 5 speeds and personally I wouldn't class it anywhere near one of the best. It's far too easy to get the wrong gear. Judging by the number of spec. Miatas I've seen spinning off the track from unplanned lower gear selection and the presence of add on fifth gear block out things I'm not alone.

You aren't, but I've tracked both 5 and 6 speed Miatas and never had a problem getting the right gear.

I kind of figured the Honda 3.2 V6 would be quite nice with a five speed behind it in a Ford Capri. There's always the SHO V-6 and a T-5, though, once the right bellhousing is found.

In reply to APEowner: I suspect that's a problem with the rubber Miata motor mounts more than the shifter. You load it up in second and try to shift to third but when you untorque the driveline that 2-3 shift becomes a 2-5 because everything rotated counterclockwise a few degrees. The shifter worked perfectly but the target moves while you are shifting.

KyAllroad wrote: In reply to APEowner: I suspect that's a problem with the rubber Miata motor mounts more than the shifter. You load it up in second and try to shift to third but when you untorque the driveline that 2-3 shift becomes a 2-5 because everything rotated counterclockwise a few degrees. The shifter worked perfectly but the target moves while you are shifting.

I've done a few 2-5 powershifts in my day. It's always funny.

Y'all remember how AMC was American Motors Corporation and was just a bunch of parts from other manufacturers stuffed into a different shell?

Ever think we should all come together and start GMMC? Has to be better than FCA right?

KyAllroad wrote: In reply to APEowner: I suspect that's a problem with the rubber Miata motor mounts more than the shifter. You load it up in second and try to shift to third but when you untorque the driveline that 2-3 shift becomes a 2-5 because everything rotated counterclockwise a few degrees. The shifter worked perfectly but the target moves while you are shifting.

Because the stock Miata is such a torque monster? :)

But yeah, that's the usual mechanism for hitting 2 instead of 4 on a "money shift". E36s are somewhat notorious for it, IIRC. A friend did it in my Miata once -- 15 pounds of boost, so it had more than the usual 10 lb-ft of torque. :) Fortunately I had built the bottom end to take a lot of revs, so the 8400 RPM it hit (according to the data log) didn't damage anything.

I've actually never heard anyone complain about a Miata 5-speed shift quality before. The 6-speed, yes. I have a 6-speed in mine (after grenading my old 5-speed) and while the shift quality isn't as a good as a Miata 5-speed, it's still a long way above average. I have a tranny out of an MSM, though, which is supposed to be the best available in that regard.

We just need a J to BMW adapter. My BMW would like a J35 methinks

In reply to buzzboy:

KMiata already has the BMW transmission side covered cough HINT cough

I thought I was reading that the J and K are different bellhousings? Or did I miss something...?

In reply to codrus:

That reminds me of the time a friend did the accidental 3 - 2 in a Prelude with a built H22... Normal shifting was about 9k in that thing. He said he got the clutch in right as it passed 11k The motor lived through it too!

In reply to buzzboy:

J and K do have different bolt patterns. But KMiata already has the BMW transmission side drawn out and set up. So now it would just be swapping the K bolt pattern for the J bolt pattern.

FlightService wrote: In reply to buzzboy: J and K do have different bolt patterns. But KMiata already has the BMW transmission side drawn out and set up. So now it would just be swapping the K bolt pattern for the J bolt pattern.

It's a bit more work than that. A flywheel and clutch setup also would need to be designed, and the starter location figured out. I'm sure it's doable. Perhaps it's something worth exploring once we have our K and BP setup on the market.

So far testing is going very well. Time to up the power by moving the K series into this car, and offload some of the current parts to a high power BP car for more testing.

K powered 318ti would be a riot!

I need to look away . . . Directly at my 318is

Wifey has a 2001 E46 330Ci with the 5 speed and an E30 318Ci with the M42 motor and a 5 speed before that. I don't like the short 1st and 2nd gears in either of them. I did swap the shorter diff in her convertible for the taller diff in the coupe/sedan and it helped a little.

We installed the UUC shifter and dogbone into her E46 and it made a big difference in shifting.