Gear ratio!!!!

You can't run @ 75 mph and believe you will save fuel, especially running a car carrier. There's too much drag on the unit and 75 mph is way too fast in today's world.

 

What do you mean ralph? 75mph is fine when the speed limit allows it, 75mph on the OK pike, 70mph on the ohio pike, 70 mph down through WV...shoot I run 75 all of the time and I don't feel that im a danger to any other motorists on the road...

 

you are talking to 62mph truck drivers
at 65, they get a nose bleed

these days, you are considered mentally insane if you driver over 65

 

Shoot in West Texas, if you are running under 70, better keep out of that left lane, lol.

 

I think he was referring to how drag and speed factors into fuel consumption.

 

Thanks WitchingHour>it's grade 5 science that apparently some didn't pass/understand.

 

that setup is about the same as a 10 od with 3:73 rears. your running the same rpms

 

drag really.....my 2000 classic runs 70 and 75 everyday. about 5000 miles a week...still getting 6.8 to 7.5 and once i add the polished manifold and gateless turbo and re reprogram the ecm i should be in the high 8s low 9s....its about getting your power,speed ratio correct. me i got a 500hp detroit turned to a 560 already with a super ten(putting a 13 DOD in it also) with 3:55 and lowpro 22.5 tires. when we got it it had 24.5s on it and only got 5.5 running 70 at 1450rpms when i put the 22.5 on i got 70 at 1600 rpms and 6.8-7.5....to many people thank lower rpms is better mpg when in fact once you drop out of your motors working range your burning more fuel lugging out the motor.

 

BINGO
It is all about running in the power band