Is the CVT really more efficient than the manual transmission?

[Eggman]

Top Fuel and Eggman, since you have manuals, what has been your experience with highway driving? What MPG can you achieve on a flat highway? I know it varies by temperature but just a rough estimate helps

About 50 mpg @ 60 mph, give or take. I've even noted the MID reports improved fuel economy when driving hills on the interstate highway - go figure.

[Top_Fuel]

I'd say my "real world" 60mph fuel economy is in line with what Eggman said. You can check out my fuel log. My car is driven about 400 miles/week...60% of that is freeway miles at roughly 60mph (3000 RPMs). My car has never seen 70mph...lol.

So I have the same question for those with a CVT. What is your mileage at 60mph? In theory it should be better because a CVT can do 60mph at only 2,000 RPMs.

[MightyMirageMpg]

At what speed do they both rev equal?

[3dplane]

I did not really see this stated this way for the question of why the manual is getting better mileage..

The CVT requires more power input from the engine to achieve the same power output as the manual does!

What are the losses in the manual? Bearing friction and the gears are turning in some oil that they have to overcome.

The CVT has that too and then some more!
Driving a fluid pump to create pressure that has to make it through tiny passages
to operate a valve body that operates servos to run the pulleys and the belt up and down. Apply,release clutches etc. Several seals creating friction to keep fluid under pressure where it needs to be etc. The energy to do all that comes from the gas tank!

Is there a cooler system designed for the manual to get rid of excess waste heat? No!
Is there one for the CVT? You bet there is! BECAUSE it is wasteful compared to the manual!

The energy to create that heat came from the fuel tank and could've been turned into forward motion of the vehicle
but we are transferring it to the cooling system to get rid of it through the radiator! (through a heat exchanger)

I believe despite the lower rpms of the CVT it never under any circumstances makes up for the losses compared to the manual!
This is just my opinion and could be wrong!!! But yet to see it proven one way or the other. I have not driven a CVT on a long enough drive for me to compare the readout to my manual Mirage.

Also the same reason the manual accelerates better despite the CVT holding the perfect rpm on demand of power while the manual has to run up to and past the power band of the engine as one is rowing through the gears during these intense Mirage drag races (lol).

I would love to cruise around in a CVT for a while though just to get a feel for the MPGs and make a real life comparison. I chose the manual to minimize the chances of failure in later life of the car! The MPG boost is just bonus

[MightyMirageMpg]

I believe despite the lower rpms of the CVT it never under any circumstances makes up for the losses compared to the manual!
This is just my opinion and could be wrong!!!

these intense Mirage drag races (lol).

This is what the unanswered question of the day is.

I *hypothesize* (my science teachers proud right now) the opposite is true, eventually at higher speeds (due to excessive rpm of the stick) the auto exceeds the manuals efficiency.

There's also quite a bit of real world data that suggests that.
http://mirageforum.com/forum/showthr...challenge-(PH)

It's important I say, "the automatic never becomes more efficient of a transmission" but "a more efficient method of moving the car" and never does the cvt become "easier" or "less consuming"

Without injector duty cycle information (and math) I cannot think of an actual realistic way of testing it that wouldn't be inaccurate or extremely time consuming

[IchabodCrane]

I'd say my "real world" 60mph fuel economy is in line with what Eggman said. You can check out my fuel log. My car is driven about 400 miles/week...60% of that is freeway miles at roughly 60mph (3000 RPMs). My car has never seen 70mph...lol.

So I have the same question for those with a CVT. What is your mileage at 60mph? In theory it should be better because a CVT can do 60mph at only 2,000 RPMs.

I know this is not a comprehensive study by any means but by reducing my cruise speed to 62mph from my 68mph norm I got my consumption down to 4.4L/100km on my morning commute.
with AC on and snow tires with my CVT.

[Eggman]

I got my consumption down to 4.4L/100km on my morning commute.

Down from what?

[IchabodCrane]

Down from what?

down from 5.3L/100 km.
just fyi. the trip back home tonight showed 5.0L/100km
so avg for the day 4.7 L/100km@ 62mph

[Eggman]

down from 5.3L/100 km.

That's a significant reduction in consumption for a small change in speed.

[IchabodCrane]

That's a significant reduction in consumption for a small change in speed.

yeah it is. The difference is more likely due to more aggressive throttle required to maintain the higher rate of speed. I'm travelling on Provincial highway rather than 4 lane interstate and so must make use of passing lanes and such to stay ahead of the slower vehicles.
Dropping to 60mph allows for a more relaxed pace over all.