xB final drive swap thread

[Jason@SportsCar]

Originally Posted by CrankyOldMan

Pardon the tangent, but...

I prefer to keep all three decimal places to avoid confusion with similar ratios available on variants of the C5* line. Yes, I've spent entirely too much time researching this. =)

Yaris (non Vitz RS) C50:
1st 3.545:1
2nd 1.904:1
3rd 1.310:1
4th 0.969:1
5th 0.815:1
Final 3.722:1

Vitz RS C56 close ratio:
1st 3.166:1
2nd 1.904:1
3rd 1.392:1
4th 1.301:1
5th 0.815:1
Final 4.312:1

My dream Frankensaxle:
1st 3.166:1
2nd 1.904:1
3rd 1.392:1
4th 1.031:1
5th 0.725:1
Final 4.312:1

Why go through the trouble? Well, because I hate getting stuck below the power band in second gear. The redline speed of 1st is very close to the stock, but because of the taller ratio the drop is only about 2400 rpm to second--instead of 2900. A rev-limit shift would in theory land you just over 4k, right in the sweet spot of the stock/NA torque curve. The internal ratio of 2nd is the same for all C5* series gearboxes, and the drive gear is integrated into the input shaft. Can't change it without customizing the whole shaft. The benefit here is from the shorter final drive ratio, as well as the shorter ratios in 3rd/4th. Sure, you give up a ton of theoretical top end speed, but if you don't ever plan on driving over 100mph, you'll never know it's gone.

The super-tall overdrive ratio in 5th is to compensate for highway cruising. When driving like I stole it, I don't get up into 5th anyway.

Anyway, really looking forward to see how this mod changes your corner exit speeds!

And Garm has found yet another option: http://www.yarisworld.com/forums/sho...&postcount=898

It wont be "freeway friendly", but damn, it will get you there in a hurry.