Swing
04-17-2014, 05:04 PM
I'm looking for the best gearbox with the best engine for having the best fuel usage in a mk1 Yaris (P1). Currently I'm getting over 5L/100km so up to 50MPG with my Yaris 1.0, but I cannot take it any further because this little engine is working hard on the highway, with high rpm. Earlier I owned the 1.3 version, and I got similar results quite easily, so with my slow driving, I don't need this really small engine.
So there has to be an ultimate combination of an engine with a certain gearbox to get the best fuel usage.
Wikipedia has a nice list of gearboxes suitable for the Yaris platform, the C transmissions: http://en.wikipedia.org/wiki/Toyota_C_transmission
But still a lot is unclear, for example, final gears. But for the petrol versions of the Yaris, that is probably around 4.0 for the C54 gearbox (used on 1.0 and 1.3 litre engines it seams).
I'm looking at the diesel gearbox C53, which has very long 5th gear. Not sure what the final gear is. Questions are:
- Can they be interchanged? Probably only the housing towards the engine is different because of different engine block? Driveshafts etc are the same?
- Or can you open a gearbox and use the 5th gear(s) of one gearbox inside the other, since the form factor is probably the same.. ?
I also sometimes read about changing out final drives. Is that supposed to be easy?
Another idea could be, take the 1.5 (TS or TSport) Yaris with 1NZ-FE engine (still FE, still Fuel econmy :P ) and change the gearbox to simply have a longer final drive.
Gearbox of the 1NZ-FE engine seams to be C50, which already has a longer 5th gear and a final drive of 3.722. That means it already has a pretty good rpm when you drive 100km/h, so with my current slow driving style, I probably get the same results on a 1.5 Yaris.
If I would put a longer 5th gear or a longer final drive in there, it could do very nice, coasting around on low rpm on the highway (but not too low). For the engine it should be pretty easy, getting this light car to coast around 100km/h or slower.
But if it has a final drive of 3.722, there are probably not many options for final drives. I think the longest final drive in C transmissions is 3.550, which is the C551 gearbox for newer Yaris models, or for Toyota Aygo I think.
But that's only a small difference, you would like a bigger difference to make it worthwhile. For that small difference I'm not going to open the gearbox.
Any ideas on this?
(I know the diesel Yaris is the most economic one, but road tax is way to high, and nice diesel versions are hard to find for the mk1 Yaris)
So there has to be an ultimate combination of an engine with a certain gearbox to get the best fuel usage.
Wikipedia has a nice list of gearboxes suitable for the Yaris platform, the C transmissions: http://en.wikipedia.org/wiki/Toyota_C_transmission
But still a lot is unclear, for example, final gears. But for the petrol versions of the Yaris, that is probably around 4.0 for the C54 gearbox (used on 1.0 and 1.3 litre engines it seams).
I'm looking at the diesel gearbox C53, which has very long 5th gear. Not sure what the final gear is. Questions are:
- Can they be interchanged? Probably only the housing towards the engine is different because of different engine block? Driveshafts etc are the same?
- Or can you open a gearbox and use the 5th gear(s) of one gearbox inside the other, since the form factor is probably the same.. ?
I also sometimes read about changing out final drives. Is that supposed to be easy?
Another idea could be, take the 1.5 (TS or TSport) Yaris with 1NZ-FE engine (still FE, still Fuel econmy :P ) and change the gearbox to simply have a longer final drive.
Gearbox of the 1NZ-FE engine seams to be C50, which already has a longer 5th gear and a final drive of 3.722. That means it already has a pretty good rpm when you drive 100km/h, so with my current slow driving style, I probably get the same results on a 1.5 Yaris.
If I would put a longer 5th gear or a longer final drive in there, it could do very nice, coasting around on low rpm on the highway (but not too low). For the engine it should be pretty easy, getting this light car to coast around 100km/h or slower.
But if it has a final drive of 3.722, there are probably not many options for final drives. I think the longest final drive in C transmissions is 3.550, which is the C551 gearbox for newer Yaris models, or for Toyota Aygo I think.
But that's only a small difference, you would like a bigger difference to make it worthwhile. For that small difference I'm not going to open the gearbox.
Any ideas on this?
(I know the diesel Yaris is the most economic one, but road tax is way to high, and nice diesel versions are hard to find for the mk1 Yaris)