Sequential gearbox?
 

Anybody ever heard of/seen any sort of a sequential gearbox in a Miata? I don't need/want one now, but once I get into time trials and hill climbs heavily I think it would make life simpler. Also what is up with maximum required torque?

On a second looksy, I think Rec'd refers to recommended, not required :bang:

I don't believe I've ever seen a sequential gearbox installed in a Miata.

Modifying the stock gearbox would seem to be nearly out of the question- there's just not enough space to locate a drum anywhere near the selector rods. I was going to suggest that perhaps Mendelola could come up with something, but it seems that all of their products are intended for rear / mid applications.

There are a couple of companies that make "generic" sequential gearboxes, which could be adapted to fit a Miata with the correct bellhousing and tailshaft. Here are some examples:
Hewland SGT Gearbox Specification
Elite Racing Transmissions | beagleengineering.co.uk

Know that these boxes are insanely expensive; as in $10,000+.

Another option would be to remove the whole Miata engine and transmission and install a motorcycle powerplant, such as a Suzuki Hayabusa or a BMW K1200.

I think in the end it would actually be less expensive to do a whole motorcycle powerplant transplant than those other sequentials

turbo busa miata?

Oh, cheaper by far. That $10k I posted is just for the center section. You still have to fabricate a bellhousing adapter and a tail section to actually mate it to a car.

And I'm only half kidding about the bike engine. You'd have to beef up the clutch, and probably the gears and shafts in the transmission, but there are plenty of folks who are making >300 HP on a regular basis with 'Busa engines. Remember that for a given torque, HP increases linearly with RPM; and those bikes are rev-limited to "only" 12,000 RPM in stock trim.

The most insane one I've ever heard of dynoed at just over 700 bhp. It was made clear that this was not a practical drag bike, it was purely a dyno queen.

yeah I saw the Hewland website last night when I was putting up this thread, lots o' choices. However cool the V8 busa motor idea sounds, I'll stick with the 1.6. I did notice that most sequentials have the gearbox mounted in the rear and were synchro-less. True that to thousands upon thousands of dollars too btw. Could a motorcycle transmission somehow be used somewhat successfully mated to the 1.6?

The busa is a inline 4, and was a very fast motor, but dated now. Now the new one that just came out would be wicked. But as far as the 99-06, any of the 05+ (or 06 for honda) 1000cc's are faster. But I guess if you were going to build it and turbo it. It would be wicked... But expensive
I would rather do a monster swap, or a LS1... Just my .02 cents.

I bet the Ls1 would light the tires up at 75 or 80. And I'm not talking turbo. That z28 my cousin had would stay sideways to 65 mph. and it was a automaticwith 327 gears. With the traction control on, it would still light up second. But when you turned it off. man sideways and fish tailing till 65, and had forever top end. Like 160mph.

Even with 14psi on my car, I think it would shut my miata down........

Good luck on the tranny.

have you not seen the V8's people have made utilizing 2 busa motors and custom parts?

Straight crazy..... But I like anything powerful. What people do for horsepower.LOL

Hmmm.

I mean, anything is possible if you're willing to put the effort into it. On most Japanese bikes, the engine and gearbox share a common housing, but a Harley gearbox might work- they're typically separate and connected by an external belt drive. The input and output shafts are both on the same (left) side, so some kind of mechanism would be required "reach around" with the input shaft. In fact, if I'm not mistaken, I believe the input and outptut shafts on a hog box are coaxial.

I have no idea how one would respond to the torque of an automotive-size engine.

True. I tend to fall back on the GSX-R because of name recognition and reputation. The 'Busa benefits from an enormous following in the aftermarket parts department like few other motorcycles. A Lotus Exige might be faster than a Honda Civic, but which one has more bolt-on goodies available?

Sequential shift transmissions are fantastic. But I agree, the only 'cheap' way to get one in a car would be to graft in a bike engine. The crankcase/gearbox combo are so tightly integrated in most sport bikes it would be hard to separate them without some serious custom fabrication. They are not modular like Harley transmissions.

If I had the means I would without hesitation put a high-RPM V8 (like the Busa based V8 above) in a Miata. Just the sound alone would be worth it.

Standing in turn one, when the first lap of an endurance race is being completed at TWS, and 20 or 30 high-rpm bikes are flying down the front straight, near redline, bearing down on you doing 140MPH+ (after slowing down a bit)... the sound makes me misty nearly. I need to record it in stereo sometime. It is simply beautiful.

that V8 busa motor made by the Radical guys comes out to a cool $32,000... for the small one :mad: Guess my best bet would be to get the NMT 6 speed offered by Hewland

A while back, I saw a clip of the Suzuki Stratosphere being revved up at the Tokyo show. For those unaware, this is an inline-6, ripping up to >10,000 RPM. The sound was... moving.

This has really got to to wondering about the feasibility of such a conversion. It wouldn't be impossible to split a Jap case in half and weld it up, and it'd be downright easy to use a Harley box. The big question in my mind is whether it'd survive.

yeah I think its limits would be well pushed on a stock Miata, much less something pumping out near 300 ft/lb's. Do the BMW bikes have an integrated gearbox? I think some of them are driven by a drive shaft, that could make things easier?

well they have a ton of busa powered smart cars, and while the miata is heavier its still not TOO much more. I would think a boosted busa engine/tranny would be ridiculous on a miata, though not very practical.

with v8 engine/tranny swaps available nowadays with kits to ease the process, I think that is the best way to go if you wanna go for big power and a reliable tranny. I mean a smashed z28 sells at auctions for cheap, a buddy of mine just bought one for 2200. keep engine/tranny/etc and part out the rest, and I'm sure you could get 1000 back. IMO its very possible to complete a v8 miata for under 10k, even 8 if you can fab up some of your own parts instead of paying ridiculous money for companies to make you a "kit". buy everything used, put some work into it, and you have a fast car with a ridiculous power/torque curve. if you get bored (which is crazy) you can always cam that v8 engine or stick a blower on it, in which case good luck staying alive

On the old ones, the gearbox was a separate unit, but mated to the engine in a really odd way. But that's an intriguing idea- they are correctly set up with the input and output shafts on opposite sides.

On the newer transverse bikes it wouldn't work, as the input is turned 90° relative to the output shaft.

The problem I see is that a Miata engine produces a hell of a lot more torque than any bike engine. That's what kills transmissions.

I've torn down/reassembled a couple of Japanese bike engines. The transmission 'casing' is so integrated into the main case that there would not be much left by the time it was separated; plus a lot of the structural integrity of the case would be lost. There is not a lot of extra material on a bike engine/trans. They are very optimized designs with thin wall cases.

By the time all of the damage was properly corrected/adapted it would probably be easier to just machine a new transmission housing for the bike sequential gear set. The output shaft on the bike is already splined for the chain sprocket so that could probably be adapted to a driveshaft. The transmission input shaft is a different story. A lot of them are gear drive from the crank to the trans input (through the clutch) so that would need to be dealt with. Turning the input gear into a swash plate mount or something like that could work. Then there is the WET clutch to deal with... And the lack of a reverse gear... and the output shaft offset when the engine is centered in the chassis... you get the picture.

Not saying it cannot be done, and these things have been solved for kit cars, but damn, at that point I'd rather just have a Super 7. In fact you can go to the Super 7 site and see the assembly they fabricated for the Busa adaptation.

Even if I did my dream V8 Busa engine conversion, I'd just put a really nice regular shift 6-speed in it.

I suppose the older BMW shaft driven transmission could work, cryo the internals and use on a race only application, where reverse wouldn't be necessary (i don't think it would at least). Plausible?

1st to 5th Straight Cut Dog Set - Mazda - Pfitzner Performance Gearbox

I have no idea what the price is ...

product inquired! that would be odd though, and I'm not sure that not operating the clutch would save time while still moving the H pattern. And 1st being in 5th's place kind of baffled me, until I though about how often you would use 1st gear, so you would just be working 4 gears in a tight H pattern..... hm... I wish they would have replaced gear 2 with 4th gear, that would make things easier, only requiring a horizontal change on the 3-4 shift

god I want a dog box just for the noise lol

Look at mnet. I.e. Boig's car.
IIRC Mazdacomp sell the Miata tranny - a straight gear, sequential dog box and the name is MRT-1 (Mazda Race Transmission). According to Gibb the price is $14K.

raceonusa used to get HKS S.MT's for 12k. They were for the FD's and at the time I had mine, I was super close to getting one but then I was 2k short of affording it. They dont carry them anymore but im sure it could be made to fit one of our cars

I've looked into various options on gearboxs as i need a Auto.

As everyone else already said even used Sequential boxes go for 3 times the value of most Miata's.

How about a tranny with paddle shifts though?
Most paddle shift gearboxes have the option of push/pull on the gearstick sequential type gear shifting.

I made enquires about the various VAG DSG boxes, but they're 4wd and mounted the wrong way.
The BMW M3 SMG gearbox looked like a option, but electronically at least it's pretty much 1 package with the motor and the M3 motor is too tall to fit in a Miata.

There are some companies that offer paddle shift kits for various slush boxes, but i can't imagine anything worse than competing in circuit racing with a slushbox.

Is there not any US cars with DSG, SMG boxes that are rwd?



Cheers
Mark

Even in race apps, reverse is often required by the rules. SCCA Solo for sure, except in a couple of specific classes. But reverse is easy, Quaife sells an inline reversing box which is what all the MC-powered LoCosts use: AUTOTECH - Quaife Torque Biasing Differentials, Close Ratio Gearkits, Racing Transmissions, Custom Driveline Components


Got a link? You have aroused my curiosity.


It depends on the auto.

The flappy-paddle gearboxes that you see on high-end applications like formula cars, Ferraris, and Nissan GTRs are internally quite similar to manual transmissions. They use syncromesh gears and have computer-controlled clutches.

But the vast majority of paddle-shift transmissions on "regular" cars are in fact bog-standard automatics where the control system for the hydraulic solenoids incorporates a semi-manual input interface. Internally, they still have torque converters and planetary gears. This is not to say that it's impossible to build an automatic which shifts nicely (the drag guys have elevated this to an art form) however I've never seen a Miata automatic set up in such a way as would be acceptable to a stick-shift purist.

Here is the web page of Boig's car (check pages 1,2,3 - alas no pic of the transmission itself):

http://www.cardomain.com/ride/350414

The $14K I remember from few threads at mnet where GibbP mentioned the sequential transmission bolted to Miata engine and the price

I saw prices like $12K and $14K for places I've never heard of, when for that price I could get a gearbox from a very reputable company such as Hewland for about $8000 with 6 forwards and 1 reverse gear (this gearbox also has a Powerflow differential, which I have no idea what it is), and is capable of handling 240 lb. ft. of torque, which would put us in what about the 260-270 HP range?

Hewland FTR Gearbox Specification

mazdacomp's transmissions

http://www.mazdamotorsports.com/pdfs...ansmission.pdf

One little problem- that box you linked to is a transaxle, intended for mid-engine applications. That's why it includes a diff.

Hewland has three front engine, rwd boxes, which are listed as "in tunnel" on their main specs page. They are the MVE-STA, the SGT, and the IGT-C.

I can't find the MVE-STA on any price sheets, but the SGT is £10,020 ($15,312) and the IGT-C is £12,385 ($18,926). And that's just for the bare gearbox itself- you still need to have a custom bellhousing made.

Ikeya Formula makes an adapter for many cars to change the H-pattern to sequential, unfortunately they don't make one for the Miata....

PRODUCT INFORMATION

well joe I take it those are for longitudinal mid engine applications? If so couldn't one just mount the gearbox back there corvette style? I know the space would be non existent, but if your already going through the hassle of mounting this to a car, making room shouldn't be out of the question

karter i suppose one could adapt an RX-7 transmission to a miata. However the site lacks information such as how the hell this works. It might switch it to a sequential type gearbox, but I see no mention of dog gears. :confused:

ok I hypothesize something. Get an FD transmission, buy the IKEYA sequential conversion, and then throw in the PFITZNER RX-7 gears, so that one could utilize a sequential clutchless shift. What do ya think?

I found some info on putting in the FD transmission

http://forum.miata.net/vb/showthread.php?t=224897

apparently there are also adapter plates, but i can't find them

Hehe that's nice, keeps reving and reving. Fun stuff.

ok well I got back information from Pfitzer aka PPG (didn't know they were one and the same) and

We are nil-stock on this product and will not be putting it back into production until we receive orders for 5 or more sets which may be mid this year. The cost was approximately $7800aud

so we're talking $5455.32 for the Miata dog gears, and then another $1573.03 for the Ikea sequential shifter for an FD (silly me forgot to ask about the RX-7's gears instead of the Miata's, but I am sure they are close in price). Throw in an FD transmission, some sort of fancy adapter plate to fit the transmission to Miata, and for $7428.35 (roughly) you could have yourself a bulletproof sequential gearbox for the miata.

Just google ikeya formula, there is a small bit of info on it. It is an extremely well engineered piece that does the normal H-pattern movement for the transmission from the normal sequential motion the driver does. In other words, it does the H pattern shifting for you, transforming your experience into a sequential shifter.

yeah and thinking it was as simple bit of kit, I asked a few people I found who had them that if you kept upshifting it would unknowingly shift into reverse, but somehow depending on which car they have blocked out the reverse gear unless you pull a special tab. Really piece o' machinery.

the ikeya thing looks nice :)
wouldn't sadev be able to make/convert a miata compatible sequential box?

Apparently Quaife is currently in development of a Miata sequential gearbox for about $7500.

Cha ching... I guess if you really, REALLY want one, or are racing and have to have it to be competitive, but damn... There are some other things I would rather have for that kind of money; that is some significant opportunity cost.

Invoke: Dave the Resurrector.


Something has just occurred to me. It's based upon a sequential conversion mechanism that I once saw for the VW Type 1 transaxle.

Take the drum and ratchet out of a motorcycle gearbox, and fit it into a small enclosure that can be mounted in a remote part of the car, such as behind the diff.

Instead of three shift rods, fit the drum with three shift cables.

Open the Miata transmission. Remove the main shift rod and shifter turret. Attach one of the shift cables directly to the end of each selector shaft.

Just read through this for the first time. I don't have a lot of technical knowledge with trannys, but didn't the 3rd gen MR2 come with an optional 6 speed sequential? Granted it is sitting sideways in the rear of the car, might that be a plausible solution?

FWD trannys have the diff built into them. Basically rendering it useless for a rwd application.

That's a fairly clever bit of thinking Joe... Push-Pull Cables aren't particularly hard nor expensive to have made, we do them for throttles fairly regularly.

See here... PUSH-PULL.COM This is who does all our cables.

One thing I'd point out that I hadn't seen mentioned earlier... the sound "dog" boxes make doesn't have anything to do with the dog vs synchro gear engagement. The sound comes from the gears being straight cut rather than helical.

Thanks. They're pretty common in marine applications, in many OEM FWD shifters, in rear-to-mid transaxle conversions (think VW / Porsche) etc., as well.

I came into the idea while thinking about how to convert a VW transaxle to computer control, using solenoids or linear motors rather than cables, but the principle would be the same.

I've never opened a M/C gearbox (they scare me) but I am assuming that you basically have three selector forks (or rods) riding on the drum, such that each increment of the drum causes one fork to move to the neutral position, and another to the engaged position.

Now, whether or not any M/C box uses a gear pairing that is compatible with an H-pattern is another question, and one I don't know the answer to. IOW, 1-2 on one fork, 3-4 on another, and 5-6 on another.

Eh?

I don't recall seeing anybody refer to the sound of the gearbox, unless you're talking about mazda/nissan's (incorrect) reference to FM's Quaife gearset. While not absolutely straight, that gearset does have a much shallower helix angle, and is thus likely louder. But you're right, in that it obviously retains the stock synchros.

Still, I wouldn't want a dog box on the street even if I could get one. My focus here is entirely about how to convert from an H-pattern shifter to an inline shifter, so as to alleviate the possibility of incorrect shifts.

The reason I brought up the straight (dog) gears is that it would aid in the sequential process. Now I just have to look up wtf Joe is talking about.

Short version:

Straight-cut gears have nothing to do with dogs. A dog box can use helical gears, and a synchro gearbox can use straight gears.

Ah, I thought a dog box utilized straight cut gears, thank yee. But the straight gears is what gives it strength vs. the helical?

And I meant wtf about your VW transaxle. I am afraid I know nothing about VW's.

This was the quote that made me think that people could be confusing the sound of racing boxes as coming from the dog engagement vs the straight cut gears...

Most dog boxes DO use straight gears, the reason they do that though is because they're primarily racing pieces and yes straight cut gears are stronger and don't load the shafts axially like a helical gear does. One other reason not to use dog engagement on a street car... the dog rings get replaced fairly regularly.

Joe, I don't really know anything about bike trannies unfortunately so your guess is as good as mine about how exactly they transfer drum to fork motion inside the box. I wonder if anyone has a broken sportbike lying around...

Tex seems to know his way around a bike...

Oh.

The transaxles used in the air-cooled models were sort of semi-modular, in that the nosecone (where the shifter terminated at) could be removed from the main body of the transmission, exposing the ends of the selector rods themselves. You could then bolt a different system on, to convert to a side-shift mechanism, a hydraulic shifter, etc.

A while back, as a sort of thought experiment, I was toying with the idea of cutting down a VW transaxle (removing the whole bellhousing / clutch section) and using it as a differential for a bike engine. Figured that as a bonus, a person could retain the stock 3'rd gear as well as 4'th, thus obtaining a high / low range selector, as well as retaining the stock reverse gear. To avoid having to run an additional shifter, I thought it'd be interesting to go electric, with linear motors directly operating the forks.


That part is actually pretty straightforward:

http://img40.imagefra.me/img/img40/2...9m_c0347c0.gif

The three shift forks slide side-to-side on the shaft. The tabs (in green) ride in grooves on the drum. As the drum rotates, it causes the forks to move.

Here's another example, in which the three forks are split across two different shafts.

http://www.gadgetjq.com/transmission%20r1150gs.gif

Normally the forks engage the dogs directly. Instead, attach one cable to each fork.

The trick is to find a transmission which uses a gear pairing which is compatible with the H-pattern. IOW, 1-2 must share a fork, 3-4 another, and 5-6 another. The more drum pictures I look at, the less I'm convinced we'll find that combo. It seems that the transition from any gear to any other gear always seems to involve two different forks for some reason.

ok I get it now ;)

Your electronic controlling now has me amused though...

Looking at the above examples it looks like you'd need a few basic things to roll your own...

1) Steal the drum ratchet mechanism from a bike trans.

2) Measure the needed shift fork movement

3) Fab up extensions from shift rod to drum

4) Have a drum CNC cut

5) Fab a housing for the above

Am I missing anything?

6) Profit!

Seriously, though. I fear that by the time you start having new drums cut on a CNC machine and such, the "low budget" nature of this particular approach is lost. At that point, it would likely be just as well to adopt an Ikeya-style design.

Thinking about this further since my last post I'm inclined to agree that either copying the Ikeya style or modifying an existing one to work is probably the easiest and most likely cheapest solution.

Any number of Japanese gearboxes have similar gearshift mechanisms, for instance the Toyota T50 in my Locost is nearly identical in shifter operation to a Miata 5 spd (the location of the miata in a turret is different, the actuation method almost identical). That said it seems like the challenges in adapting an Ikeya would be:
1) Find a box with similar actuation method and length/width of shift gates at the shift rod.
2) Fab an adapter to attach the mechanism to the box.

Without having seen an blown apart Ikeya in person I'm not sure how easily modded for varying shift gate throws they might be.

Well, they offer one for the FD.

Any of you triangle-heads know how similar the FD tranny's gear selector is to the Miata's?

I've considered this a bit myself and come to the following conclusions:

1.) A Bus (Hayabusa) makes more torque than a 1.6L Miata engine almost everywhere. With the 200+lb weight savings of going from the Miata iron block and diesel transmission to a Bus motor, I think you'd have a fantastic street car. The Quaife inline reverser box is $1600, but Champion Motorcars (a defunct Locost kit builder) used a much cheaper, much simpler box. I'm sure the manufacturer could be found. The transmission on the Bus motor would have a hard time with the abuse, and you'd burn up clutches pretty fast, but they're very easy to swap out. Adapter flanges already exist to attach universal/ CV joints onto the Bus output shaft. With an aftermarket gearset, tool steel shift rods, billet shift forks, and a super bad ass clutch setup (solid hub, APE plates, super stiff springs) you could probably get by for a LONG time. With a really stripped track day/ street/ F Mod (Street Mod?) autocross toy you could possibly keep it together forever.

Now that I write all that down... I'll be needing a Miata roller.


2.) The aftermarket Harley transmissions are <$3k, and almost all of them can be had in right side drive (correct input/ output shaft arrangement). And if they can make a ~1200lb Harley Desk Glide reliable with ~145hp, you could keep one alive behind a mild ~100hp 2000 lb Miata, I'm sure. If you had a clutch basket and hub machined to use dry Ducati clutch plates, and the Revtech/ whatever input shaft, and a small bell housing to mate the trans to the back of the Miata block, you wouldn't have to run the clutch in an oil bath, and you could put as many plates in it as you wanted, meaning you could keep the clutch alive forever with all that thermal mass and surface area. That does kind of limit you to a really mild motor or a really light Miata though, unless the trans manufacturers think they're product is a tremendous amount tougher than I do.

3.) If I were going to do any silly bike engine swaps into a Miata other than a Hayabusa, I'd do a Honda Goldwing. Think about it: 1800ccs, enough torque to clutch up wheelie a 900lb bike in 3rd gear, simple, symmetrical, almost centered shaft drive output shaft, reverse... They sound SICK uncorked, they're Honda indestructible, they're light(ish). Just a thought.

I don't personally think a Bike engine Miata would work particularly well anywhere other than on track. The bike engine Locost guys are pretty abusive to the clutches already, and Miatas weigh at least 50% to 100% more than a Locost, depending on how stripped the Miata is. I can't see a sportbike trans/clutch living long doing street duty stop and go lugging around 4-6 times the weight it was designed for.

That said I agree with your Leadwing idea... that flat 6 in a light mid-engine chassis would be sweet.

Boxster did it...

If clutches were the only worry, I'd be all over this. The clutch would face forward on a longitudinally mounted engine, so you would just pull the cover (8-10 6mm allens), pull the 6 pressure plate bolts (6 8mm allens), pull the old plates, stuff in the new plates, reassemble, top off the oil, recommence to boogy. I'd be more afraid of what happens to the shift forks/ drum after a weekend of track days. A careful driver would never hurt them, but KWS's rider last year (Ben Thompson) could smash a set of shift forks to pieces in an afternoon of practice and qualifying. Every missed shift or careless down shift wears on the pads on the forks, and every over zealous shift in either direction wears the drum lugs off the forks, and beats the life out of the drums...