Which speed in 6th gear (6MT) for best economy?

[JoeFromPA]

It's got to be driving conditions - I spend a good amount of time off throttle or cruising and get phenomenal results. When I accelerate (and the car is warm), I'm using 50-75% throttle in sport mode all the time and going up to 4000-5000 rpms before shifting, at least in the lower gears. I'm on winter tires, so WOT in lower gears is not my friend at the moment.

[purdyawesome]

What the hell is this "6th gear" you guys speak off??

[bruce.augenstein@comcast.]

Originally Posted by JoeFromPA

The load on the engine in the selected gear also impacts it. A higher load at 1500 rpms to sustain speed than a lower load at 2000 rpms to sustain speed may mean you want the higher RPM (i.e. higher speed) to get ideal fuel economy.

It's actually pretty much the opposite - assuming that what you mean by higher load means that you have to push the loud pedal down more to maintain speed at 1500 rpm than at 2000 rpm. In that case, opening the throttle further at 1500 rpm reduces pumping losses, thereby increasing mileage.

Increasing speed means more power is needed, thereby increasing fuel usage in general.

So, sixth gear at 1500 rpm buys you best mileage, unless this motor can comfortably cruise at an even lower rpm, with even more throttle, reducing pumping losses even more.

Bruce

[ScottF32]

Silly me! I thought my B38 was designed for best mileage at 80mph!

IIRC, I run about 3100-3200rpm to attain 80mph.

I've regularly achieved 33+mpg at 80 mph... In town, IF I can keep my foot out of it, I get about 23mpg average. More typically, 21-22mpg... Which is better than my classic LT1 Chevy!

I love road trips! Can't wait for the next one!! Haha!!