And here is exactly why I went with an early Celica transmission for my v6 project. Since my car will probably only have a bit more than 200 crank HP, I wanted to keep the NA MR2's mechanical advantage but raise my potential top speed to about 140. That should be a pretty reasonable goal given the HP I will be working with.

Excellent information - and thanks for sharing all your hard work.

 

awesome man, just awesome. Thanks for all the work and research you've done, and thanks again for sharing it.

 

Jason,
Awesome info.

I'd be a little wary of mixing and matching some ring and pinion gears. I can see going a tooth in either direction on either gear, but dealing with a range of 16-19 teeth on the pinion and 67-71 on the ring has got to get tricky at either end of the spectrum. You're talking about a 19% change in pinion teeth and a 6% change in ring gear teeth. That's a heck of a lot of gear lash, but the data is great to have. Can you drum up similar info for the E series trannies? I thought the all-trac came with a tall final in it.

 

I'm going with a standard S51 out of a late Camry/Solara for my S/C'd 1MZ project. I think it will be a good compromise between not too buzzy on the freeway and agressive gearing for the track. Wont need to shift to 5th till 115mph or so (@ around 6000rpm w/ 245/40-17 tires). Freeway 80mph cruise will be livable 3130rpm.

The S51 with the 4.176 final would be a better choice for a dedicated track car with more agressive gearing overall. Gear limited top speed of about 150mph (w/ stock rev limit). Probably useless 1st, but who uses first on a track?

I think erioshi choice for an NA 1MZ is a good one, too.
Thanks for all the good info, Jason :thumbup

 

Jason,
Awesome info.

I'd be a little wary of mixing and matching some ring and pinion gears. I can see going a tooth in either direction on either gear, but dealing with a range of 16-19 teeth on the pinion and 67-71 on the ring has got to get tricky at either end of the spectrum. You're talking about a 19% change in pinion teeth and a 6% change in ring gear teeth. That's a heck of a lot of gear lash, but the data is great to have. Can you drum up similar info for the E series trannies? I thought the all-trac came with a tall final in it.

I was a bit wary as well. Since the C50 uses a 67 tooth ring gear and an 18 tooth output shaft drive gear, I was thinking of going with that. But, how much can Toyota really change if they both share the same differential? Could the output shaft drive gear on the C50 with 18 teeth be designed differently to fit a 67 tooth ring gear? The way I see it is, Toyota just designed ring gears and output shaft drive gears with gear lash in mind. Could they have designed them in a way to minimize it or did they just redesign each output shaft drive gear to match a ring gear within one tooth each other, like the C50 and C150 with their 18 and 19 tooth output shaft gears and the same 67 tooth ring gear?

But even Toyota used the same 71 tooth ring gear with 3 different output shaft drive gear teeth: 17, 18 and 19. They also used the same 67 tooth ring gear with 3 different output shaft drive gears as well: 17, 18, and 19. Unforunately, Toyota does not provide part numbers for the output shaft drive gear since it's part of the output shaft itself, so it's not like I can see if these gears are shared between transmissions. Perhaps it is in the way they design the drive gears? My S51 has virtually no gear lash at all. The ring gear mates perfectly to the 18 tooth drive gear. The same with the S54 with 17 teeth. They both look the same.

 

You are putting too much emphasis on the model number regarding gear ratios. There are many, many different sets of ratios for most of the C, S, and E trannies depending on the engine they were mated up with (and revision), the chassis they were going into, and the tires on the vehicle. In the last 20 years, they're about 20 sets of gear ratios used in this class of tranny. I had a spreadsheet with most everythign produced since the mid-70's, but I'm too lazy to dig it up at the moment. Randy might have a copy - I sent one to someone at some point.

But you're definately right about one thing (actually pretty much all of it ) - there are a very small number of different 1st gear combos, second gear combos, etc. It's the entire package of all 5 gears plus final drive that makes the complete set. If you plot the set of all 5 gears on a spreadsheet graph, you can see some transmissions that have nice evenly spaced gearing and some that look a little cock-eyed being short between some gears and long between others.

The paragraph about Randy's transmission setup is the gem - Randy has the absolute best tranny setup there is from a racing application standpoint. His setup gets the highest possible speed in 2nd gear using OTS parts, but it was either the gears or the donor tranny bits that were only produced for about 2 years that makes things difficult to actually piece together.

One thing to note is that 1st and second gear are part of the input shaft and the final drive is part of the output shaft. So as far as mixing and matching parts from trannies, your are stuck with 1 and 2 from the input shaft and final drive from the output shaft, so that leaves 3,4,5 that you have any flexibility with. And the shaft diameter change in the S only makes things a pain. I would never arrange a combo of gears that were not mated by Toyota to keep the gear lash perfect.

My experience with the high torque of the V6's in the MR2's says there's plenty of torque - go for max speed in any gear except 5th - select that based on what you think your max speed *should* be. No sense in gearing for 160 if the power/aero can't get you past 140. For street use, just use what you can get ahold of and go drive. Not that much difference in 58 and 62 MPH if you are just tooling around on the street.

I can't rememebr hat transmissions I';m using right now. One is an e153 from 99 Camry, I believe. The other is an S51 from Camry, but not sure about the year - 98, I think. I wish I had that spreadsheet.

 

It's been said before, but I just want to reiterate: the 1MZ flywheel is not compatible with any S series pressure plate. You absolutely have to use an E153 pressure plate and an S series clutch with pretty much any V6 flywheel, if you choose to use the S transmissions with a V6.

The diameter of the E153 pressure plate is just a tad bit bigger. If you use a dowel pin to try and mount an S series pressure plate to the 1MZ flywheel, the other 2 dowel pins and other bolt holes won't line up at all. Not even close.

 

I'd also like to point out the 1993+ S transmissions have double cone synchros for every gear. The previous transmissions had single synchros.

Here's a comparison of 5th gears between the old and new:

I previously thought the 5th gears of both 90-92 S51/54 and 93+ S51/54 both had single synchros, since 5th gear doesn't receive large amounts of torque or shift shock. I guess I was dead wrong, eh?

The updated synchro hub and synchro rings look way better than the single synchro ring of the previous S transmissions.

 

I will say this - The e153 form the 99 Camry does shift MUCH better and smoother than the S51 from early 90's Camry. VERY noticable difference.