Gearbox upgrade vvti

[GrahamC1234]

Hello I have a 2007 auris vvti 1.4

I was wondering what newer gearbox will fit these cars, I'd love another gear and think it would be brilliant car with a higher 5th gear or a 6th gear for motorways.

[furtula]

I'm in the same situation as you. 

2007 1.6 and 1.4 have the same gearbox. 

From 2009, the gasoline Auris has  6th gear, which gives you some 200 RPM drop in 6th gear, not really enough to justify all that work.

Also, it does not do anything significant for the consumption, so the gain is minimal.

 

If you are bothered by the engine sound, you can invest in some insulation, under the bonnet, and inside the doors.

 

[tavy]

I did some research and minimum modification is replacing both pinions of fifth gear with 1.4 diesel gearbox pinions. 

Gearbox is the same but 5-th gear ratio is differend and the differential.

This I plan to do with my Auris, but I have to find a damaged 1.4 diesel gearbox.

[Mooly]

IMO the 6th gear makes for more relaxed cruising. I just checked this morning and the 1.33L shows 3500 rpm in 5th at 70mph falling to just under 3000 in 6th. Fifth gear on the Auris seems to be the same as 5th gear on our old 1.4L Corolla rpm vs speed wise.

[furtula]

  

2 hours ago, Mooly said:

IMO the 6th gear makes for more relaxed cruising. I just checked this morning and the 1.33L shows 3500 rpm in 5th at 70mph falling to just under 3000 in 6th. Fifth gear on the Auris seems to be the same as 5th gear on our old 1.4L Corolla rpm vs speed wise.

 

On the 1st gen 1.6 Auris, in 5th gear, at 60 mph, you are at 3k rpm, so roughly 20 mph for each 1k rpm, so 70 mph would be around 3.5k rpm.

I also dislike it, but it is what it is. Yes you get more relaxed cruising with 6th gear, but MPG tends to suffer, unless you find some sweet spot.

At least from what i know from people around me with 1.6 gasoline cars and 6 speed gearbox, some complaining that their cars drop down to 35 mpg when doing 80.

 

Mind sharing your MPG figures with us, when going 60,70,80-ish ? 

 

[Mooly]

To get even approximate short term mpg would mean driving the same stretch of road for each test, all I can say is that 'averaging by eye' on the Instantaneous MPG readout shows a progressively widening improvement the faster you go when comparing 5th and 6th. At lower speeds (and 40mph is the official minimum speed for 6th according to the change indicators) the difference is minimal, and I suspect worse if you attempt to use below 40mph. About 60 to 65 mph is the most economical for cruising at speed, go above that and the MPG does start to fall.  

Fwiw my average mpg over the last 80 miles or so (and which including a longish run) is showing around 54, and it hit a high of 56 on Saturday. The previous full tank average was in the very high 40's to low 50's. The quiet roads the last few weeks have made a significant difference, probably 10% or more. 

[furtula]

My cruising speeds on highways are 60 miles, because i don't rush, take a lot of breaks, so no need to force it, and it seems like it suits the car best.

MPG with AC on, in summer months, is around 48 on average, add to that the difference between the 1.6 and 1.33 displacement and it's more or less the same.

This is on a stretch of road that is 75% highway, and the rest is hilly areas, villages where you need to stop, and accelerate, etc.

So in this case you don't really get any benefits from 6th gear, except a bit quieter engine due to RPM difference.