johnmk

Automatic transmission gear ratios:

1= 3.3
2= 1.9
3= 1.42
4= 1.00
5= 0.713
6= 0.608

Manual transmission gear ratios:

1= 3.54
2= 2.05
3= 1.38
4= 1.03
5= 0.88
6= 0.73

Keep in mind that the lower the number, the taller that gear.

So anyway, the manual is pulling higher RPMs on the highway, which leads to increased engine noise (this is actually quite noticeable vs. how quiet 6th is in the auto) and wear & tear on the engine because 2200rpms is higher than 1800rpms, not to mention a mild reduction in fuel economy compared to the automatic on the highway (we're just comparing sixth gear here folks).

Does anyone have theories as to why Toyota made these trade-offs? For a modern vehicle, a final gear ratio of 0.73 just seems so . . . 1990's, especially in a six-speed.

Does anyone know if it would be feasible to swap in some taller gears? I guess ideally, I'd like to see fifth be around 0.8, and sixth be perhaps 0.65 or so.

Aside: I'm trading in my automatic for a manual, partially because I've decided adding a turbo to my automatic transmission is just asking for trouble or super expensive and/or wasteful compromise upon compromise, and it's also a good opportunity to reach for a black tC, black being sort of a family tradition. I could spend the better part of a small fortune -- more than the turbo itself -- upgrading the internals of the automatic -- and I'd have something potent on the street, unique and which I'd be very happy with, but that only reduces reliability concerns a moderate amount. All in all, that's a very expensive route to go, vs. putting that power through a relatively simple manual transmission, which are much cheaper to maintain & repair.

Backinblacktc2

iTrader: (1)

Try contacting world-racing / descendant and see if they have a solution to your problem.


Mike Alejos
WORLD Racing Inc._
Web:_www.WORLD-Racing.com
Email:_malejos@world-racing.com
Office:_310-533-8900 x. 227
Direct Fax:_424-757-9028_
Cell:_714-975-1267

Vlad1024

It's probably because the engine isn't making much power that low so you would have to shift often(when passing or climbing hills) where the auto could discretely unlock the torque converter or drop down a cog. Here are the ratio's for the legacy model and the overall ratios including final drive.
Transmission: 5-speed manual

Gear Ratio Overall ratio
1st 3.54:1 14.98:1
2nd 2.05:1 8.66:1
3rd 1.33:1 5.65:1
4th 0.97:1 4.12:1
5th 0.78:1 3.28:1
Final drive ratio......................................................................4.24:1
Engine rpm @ 60 mph in top gear.........................2700

Stop complaining.

johnmk

Hi Backinblacktc2 -- thank you, I might give them a call.

Vlad1024 -- perhaps you don't understand my goal. I'm interested in an intellectual conversation, I don't really think of these things as problems per se. Thank you for posting those numbers, by the way -- I have an autistic fascination with numbers. Who knows, maybe I'm a closet aspie?

Vlad1024

Since this forum seems abandoned I'll add something. Slightly higher RPM's won't cause much(if any) wear on an engine; load will. In some cases it's better to let the engine spin faster than to lug it. Even though everything is moving faster the forces on the con-rods and bearings are lower at a certain load at 1500 than at 2500 rpm which leads to (marginally)less wear. As I said before, the torque converter lets the engine rev up out of the basement without shifting gears so the ratios can taller while reducing load on engine internals(by increasing rpm).