Tested rpm-mpg

[BHarvey]

I ran a test for baseline and did it 3 times to verify.

57 mph on cruise on a 10 mile stretch with a couple decent climbs/descents.

6th gear= 2000 rpm and 49 mpg
5th gear= 2490 rpm and 44.5 mpg
4th gear= 3000 rpm and 39 mpg

Seems to show that less rpm is certainly better. I have room to go up on tire height but 27.5"-28" OD would be maximum. Current tires are 25.5" OD so around a 10% reduction in tire rpm will net how many less rpm's?

[basjoos]

This shows the potential mileage that the manufacturers of all of those high cruising RPM MT cars are leaving on the table that could be attained via an inexpensive gear ratio change. Those 40mpg MT Fits and Yarisis could easily be 50mpg cars running in Prius and Civic hybrid mpg territory if they were geared properly for highway cruising and their engines would also last longer.

[UFO]

10%

[bwilson4web]

Originally Posted by BHarvey

I ran a test for baseline and did it 3 times to verify.

57 mph on cruise on a 10 mile stretch with a couple decent climbs/descents.

6th gear= 2000 rpm and 49 mpg
5th gear= 2490 rpm and 44.5 mpg
4th gear= 3000 rpm and 39 mpg

Seems to show that less rpm is certainly better. I have room to go up on tire height but 27.5"-28" OD would be maximum. Current tires are 25.5" OD so around a 10% reduction in tire rpm will net how many less rpm's?

When you change tire diameter, any vehicle specific MPG meters will be off as will the speedometer. You'll need to recalibrate or use a correction factor, 10%, to be able to compare with your baseline.

LATE THOUGHT: Rather than buying four new tires, buy one and a full-size rim. Then put it on a front and later rear wheel to test for interference. It is a lot easier to 'eat' the cost of one tire than four.

You can also get just a second tire and then put them on the drive wheels. Often this is enough to test your hypothesis about revs/mile and vehicle efficiency without having to put so much money into tires.

Bob Wilson

[BHarvey]

My odo is 2.8% low compared to my GPS anyway so recalibration would not be a problem.

10% would be a start as it shows every little bit helps.

[Bill in Houston]

Yeah, a lot of MPG is left on the table in the Honda manuals. I would love to know what my Element could do at, say 2300 rpm vs 3500 rpm when cruising...

[mcrews]

is it a 4 or V6?
It will probably drop your rpms to 17-1800. Which could be a sweet spot for a 6. I don;t about the 4 bangers.

But given the potential drop in rpm, It would be worth it.

[Allch Chcar]

Originally Posted by mcrews

is it a 4 or V6?
It will probably drop your rpms to 17-1800. Which could be a sweet spot for a 6. I don;t about the 4 bangers.

But given the potential drop in rpm, It would be worth it.

The v6 Sonata is gone as of the '11 model, replaced by the turbo 4.

But we also have the Garage for that sort of question .BHarvey's '11 Sonata

The CR-Z runs 2400-2500RPM at 60mph and it's only a 1.5L in a 2600lb car. Some of those guys are getting 40's to 50mpg tanks

Most manual 4 bangers run high 2000's to 3000RPM at 60mph. That leaves a lot of room for improvement and people are going complain to complain either way about these cars being underpowered .

[pounsfos]

Originally Posted by Allch Chcar

The v6 Sonata is gone as of the '11 model, replaced by the turbo 4.

Most manual 4 bangers run high 2000's to 3000RPM at 60mph. That leaves a lot of room for improvement and people are going complain to complain either way about these cars being underpowered .

my 29 year old car at 60mph (97ish kph) turns 4300rpm
and i still get high mpg's imagine wgat i would do if it had the power to turn lower rpm

cant wait till i put my fuel injection setup on, it'l be nice to get some waaay higher mpgs

[BHarvey]

I don't know why people complain about power, it will spin it up in first gear and start to in second, and this is with TC on!