Toyota Matrix XRS 6th Gear Swap?

[highway_star]

Looking to get some well informed and thought out analysis on this.

I have a Toyota Matrix XRS, which came from the factory with the 2ZZ engine and 6 speed manual C60 transmissionmission.
Due one or more oil leaks, 20 year old rubber in the gaskets, and a clutch reaching end of life I'm planning on just doing a one and done overhaul to replace seals, clutch, etc. I figure its easier to pull the transmission axle and do it all in one go and be set rather than try to work on seals in a cramped engine bay here or there.

This also gives me the opportunity to upgrade the transmissionmission a bit. I am fairly sure I do not have an LSD in this car, so I plan on adding one to protect the transmissionmission and improve performance in low traction conditions.

While I was looking into that, I ran across a 6th gear swap being offered for this transmissionmission to get an extra long gear. Per the transmissionmission calculator this would drop cruising RPM in 6th gear from 3200 to 2850 or so.

One of the things I like least about this car is the very high RPM at highway cruise due to the noise it generates so this caught my eye right away.

Besides noise reduction, I'm guessing this may reduce fuel consumption and engine wear, although both of those are perhaps up to some debate. Downside will be downshifting becoming necessary at a lower grade/weight/wind combination that previously.

Does anyone have any experience with moving to a longer overdrive gear in these cars or anything similar? Or any great blackboard insights on how this would work out in practice?

 

[nwjones18]

I think it'd be worth doing if you are already going that far. My poor Mazda just has the 5 speed and it is screaming between 3500-4000 at 80mph.

 

[Patman]

I think it'd be worth doing if you are already going that far. My poor Mazda just has the 5 speed and it is screaming between 3500-4000 at 80mph.

That’s high! By way of comparison, my Corvette’s engine is at 1500 rpm at 80mph in 8th gear. The rear end ratio is a very tall 2.41 to 1. (and the 8th gear ratio is 0.65 to 1)

 

[AdmiralYoda]

I'd do it if the price is right and you have the skills to do it!

This post brought back memories. 10-15 years ago I used to frequent a hypermiler/MPG forum. 9 times out of 10 a manual is more fuel efficient than an automatic and the common complaint on these MPG forums was the gearing of the manual transmissions.

The assumption was that the manual transmissions were geared excessively forcing the RPM's to be too high to be the most fuel efficient. A common modification was a final drive gear swap or 5th/6th gear to reduce RPM's and dramatically improve fuel economy.

At a time when fuel efficiency was a very big deal, the conspiracy theory was that the manufacturers "supposedly" geared the manual transmissions high on purpose to force customers towards a more expensive (and profitable) automatic transmission. If all vehicles were offered with a manual transmission that got 2+mpg more and cost $2,000 less there would be a lot more on the road.