CR says 60 MPH = 3495 RPM

[toronado455]

Originally Posted by ceric

Gee, who am I gonna believe, CR or MotorTrend?

CR.

[hyo silver]

After riding motorcycles with a redline over 10,000 rpm, even 3,500 seems awfully slow.

[bwilson4web]

Originally Posted by adrick71

Nope, not hard at all. Press the accelerator pedal, and the car goes. Press the brake pedal, and the car stops. What do I need a tach for? The engine speed tells me nothing useful and is likely to change constantly as I'm driving down the road. It would get annoying to see the needle jumping up and down constantly.

There is good evidence that keeping your ICE rpm below 2,600 rpm improves overall mileage.

Bob Wilson

[Danny Hamilton]

Originally Posted by bwilson4web

There is good evidence that keeping your ICE rpm below 2,600 rpm improves overall mileage.

Agreed. However, I was responding to a comment of:

Do any hybrids have tachs. I think it would be hard to have a car without a tach.

Had the comment been, "Do any hybrids have tachs. I think it would be hard to optimize your mileage without a tach." I would have agreed with the comment in the first place.

There is nothing hard about having a car without a tach. And if you are planning on trying to optimize your mileage, then there is aftermarket equipment you can purchase for the Prius to assist you.

So if you insist on having a tach, you can get one for the Prius.

[toronado455]

Originally Posted by bwilson4web

The problem is the engine rpm is not fixed but in normal operation can vary at 60 mph from 1,000-5,000 rpm and each is perfectly viable. Unlike all other vehicles, there is no fixed ratio gearing so the rpm is all over the place. That is what continuously variable transmission means.

Consumer Reports has tested several CVT cars. In order to publish a "RPM@60MPH" spec, they must have a test that uses a perfectly flat road surface and I'm sure they must try to do the test in neutral wind conditions also.

Here are the specs they publish for some other CVT cars:

Toyota Camry Hybrid: RPM@60MPH=1700
Honda Civic Hybrid: RPM@60MPH=1810
Nissan Altima 4-cyl: RPM@60MPH=1940
Nissan Altima V6: RPM@60MPH=1945
Nissan Versa: RPM@60MPH=2050

So clearly, several cars with no fixed gearing can be put through their test and come out with an accurate ICE number. Even if there is some fluctuation in the ICE RPM during the test, they must have some way of averaging it so that they can publish something relevant.

Now look at the Prius number:

Toyota Prius: RPM@60MPH=3495 Holy Cow!!!

Clearly it must be the MG2 number, not the ICE number. And they need to include of explanation or else, better still, just give us the ICE number like they do on all the other CVT cars they test.

[Danny Hamilton]

Originally Posted by toronado455

Toyota Prius: RPM@60MPH=3495 Holy Cow!!!

I haven't read the CR article, but in this thread there is just too much missing information.

What was the state of charge of the HV battery?
What was the engine coolant temp?
What stage of operation was the Prius in?
Had it most recently accelerated or decelerated?

I agree that it sounds like MG2, but with so much information unknown or assumed, the number is rather meaningless.

[Frank Hudon]

lets remember here that the ICE doesn't directly power the vehicle to wit the fact that it will go into stealth and still accelerate. MG2 moves the car as it drives the chain that turns the gear reduction gear set. Plenty of pix here on PC to show that and the final drive reduction is stated as 4.113 to 1 so 3495 /4.113= wheel speed of 849.7 RPM times the circumfrence of the tire / feet = well you get the rest of the equation. The underlying fact is the ICE isn't directly connected to the wheels so ICE RPM isn't worth stating. CR looses again. Honda's IMA has the ICE directly connected to the wheels.