6th gear on NA tranny?

[WhiteMR291]

Hey, im just wondering becuase i have a spare NA mr2 tranny, if it is possible to add another gear. I know its possible with other trannys but how about the NA tranny, does anyone here know??
-Terry

[91MR2quickNA]

Hmm, well the point for a 6spd is to have the gears even closer than a 5spd, unless 5 speeds are close ratio and the 6th is a long overdrive gear for quieter cruising (kinda like the Celica GT-S's 6spd). I don't know of anyone that's done it.

What's the reasoning? (I'm curious)

[WhiteMR291]

I see exactly what your saying and your 100% correct. But the 5 speed on the NA 5sfe tranny is geared REALLY short. And by just throwing in an extra overdrive gear it would be alot easier to drive 55+ at a steady speed without going over 3500 rpm. I was just curious.
-Terry

[91MR2quickNA]

Originally Posted by WhiteMR291

I see exactly what your saying and your 100% correct. But the 5 speed on the NA 5sfe tranny is geared REALLY short. And by just throwing in an extra overdrive gear it would be alot easier to drive 55+ at a steady speed without going over 3500 rpm. I was just curious.
-Terry

You can change your differential ratio instead. The 2nd+ Gen 3S-GE's (Euro not U.S.) S54 ratio is 3.944 vs. 5S-FE's 4.176. Doing that and swapping the 5th gear from the Camry's S51 5th gear would help (0.731 vs. 0.820). I agree that 80mph @ 4,000rpm is kinda ridiculous.

[WhiteMR291]

Would you be able to help me to go about doing this? like searching for parts and listing a parts list?
-Terry

[surfun]

I also agree that the car is geared way too short! I have owned 3 MR2 NA's with 5 speeds over the years, and I always dreaded interstate driving. I would even make a point to use secondary highways instead and therefore stay at 55-65 mph...But even then, I would be zinging along at 3000+ rpms, and people thought I was some dork wanting to race their minivan or Taurus when they would hear my car zinging like I am in 3rd gear. Cruise control was jerky too, due to the revs, and a road trip was out of the question...
I have recently purchased an automatic MR2 (91) and to my surprise it is geared very low by comparison. For example, it runs around 3100 @ 85 mph (the official published figure is 2200 @ 60). Gas mileage is incredible too...basically think of it like a lightweight 4cyl Camry when it comes to fuel mileage...I average about 29-31 mpg in mixed driving, and easily make 40 on the highway.
I initially bought it as a project / daily driver, but really started liking it the more I drove it. Normally I would never want an automatic in a sporty car, but I found this to be an exception - probably since it has a Camry motor anyway, and has all of its power toward the bottom and middle of the rev range. It really just feels like the engine was designed to be mated to an automatic, which is more than likely considering how many Camrys were sold .
But then again, I understand that some people won't drive an AT no matter what, so to each his own. Also, I am sure you guys in other countries that have the "hot motor" MR2's would probably think I am nuts, but really you would just have to drive one with the 5SFE motor to understand, and there are so FEW with automatics here that it is rare to even see one, much less compare one.
If our MR2's had the engine you guys have, then it would be a different story, and the tractor gearing and 5 speed would make more sense, as it does in the first generation MR2 - the more revs the better.

Anyway, back to topic: I wonder if it would be possible to swap the diff out of the AT MR2 or possibly from a turbo MR2 (I am sure they have a taller diff.). Heck, for that matter, I would think any given Toyota diff would be taller than the NA, for example a Celica, or Camry? I would love to try a taller ratio in my 5 speed...
One more thing we must consider...we would also need the speedo gear from the donor car.

[WhiteMR291]

awesome comparison on the NA automatic mr2 with a 5sfe. I never knew it was that much better. Im thinking it would be possible to use a lot of the differentials out of different toyota trannys. But wouldnt we need the axles then too??
-Terry

[surfun]

I am sure someone has done such a swap before...hopefully someone will chirp in.

[Toysrme]

It's practically infeasible. To add an extra gear you would have to have someone custom re-make everything, including the housing!
What you can do, is have someone make you an overdrive for the entire transmission. Giving you twice as many gear ratios. Or as someone told you, swap the differential.

Money can do anything, but this is one of those situations where no amount of money is going to convince a shop that they need to take your tranny, blueprint it, and design @ build a cutom one-time transmission just for you.


Now you probably could talk someone into swapping the Toyota transmission to an entirely different transmission, provided you're wanting to spend some major bucks.

[WhiteMR291]

Yeah i really hope so, i have an NA tranny just sitting in my garage and i might jsut get rid of it if i cant do anything with it.
-Terry

[Pineapple]

You could also try to mate a 6spd tranny to the engine. It'll require adaptor plate but much easier to do.
You can give a shop money to do anything, as long as you got enough. 1 million for a 7 spd sequantial

[JekylandHyde]

You do not need to add a 6th gear to get a more comfortable cruising gear for highway driving. All you need to do is change the final drive gear and there are options for doing that.

[rony]

^ can you please explain a little further as I would also like a longer 5th

[JekylandHyde]

Happy Reading:
http://www.mr2oc.com/showthread.php?s=&threadid=62159

[JekylandHyde]

This also relates (go down the conversion to wher it changes from tires to gears), but it is about the 3sgte tranny:
http://www.mr2oc.com/showthread.php?t=62030