Is this a bad idea?
@Rogerdodger
It's not always about max acceleration. It's about getting the engine in it's most efficient operating power band. Lugging along at 1500 RPM at 70 MPH ain't it.
Too many people think getting the engine at the lowest possible RPM at cruise speed is the way to go. It's not. It's all about the engine being in its power band......or just at the beginning. Too low a cruise RPM and the first head wind or tiny hill and you're downshifting. That's not very efficient. Did the factories do it? Yup. Was it right? No way for every application. DO the math. Your final drive ratio with an 833 OD and 4.10 gears is a 2.99. With a 3.21 gear your final ratio is 2.34. That's gettin stupid. Max acceleration hasn't a thing to do with what I'm talking about here. It's about efficiency.
What RRR said above and that really is the trick.
If you can tune an engine really well, carb and ignition, chugging along at a low rpm and burning up all of the air and fuel will get you maximum mileage results.
While chugging along @ 70/75 at a super low rpm is great one way, RRR is right in saying a mild upgrade hill can have you down shifting. I experience this is my 2018 HEMI RAM 1500. It pops out of 8th gear on mile up grades. The mileage obtained over all was still very good. But I’ll tell you that when I was coming down the mountain the mileage was insane. There’s the catch 22.
If your driving a very flat landscape, your mileage will be great even though your engine isn’t making the best amount of power in the best power range. It’s also probably the least efficient. (I’m not 100% on that.)
This is where the trick of tuning your engine & carb to be the most fuel efficient it can be at the cruise rpm. You can do this with the aid of a 02 sensor, reading your plugs for that light brown ring to be up as high as possible on the porcelain, opening up the plug gaps a little bit and even more with a multiple spark box to help insure all of the fuel is used to make power.
Address every aspect from the air cleaners opening to the exhaust for easy breathing in and out with the max burning of the air and fuel and you will do well for mileage.
Also pay attention to the mixture as you travel up hill to make sure the enrichment is right otherwise the efficiency will drop requiring more pedal pushing to do the job needed.
Good luck on your tuning efforts. I often enjoyed the challenge of doing this.
