Gearing questions
Laughing Gas
Joined: Sep 2018
Posts: 1,223
Likes: 119
I'm just trying to point out that when you go to freeway gears the around town town mpg's will suffer. To get the vehicle moving with higher gears are harder on the engine and takes more fuel. For me the off the line power is more important than some need to cruise at 75 mph in a truck that was never intended to do so. My 2020 tundra has 430 rear gears and works great to do it's intended purpose, granted it has overdrive. If I needed to go faster with less rpm's the transmission would be what I would change. You need to have it accelerate on demand, I live in the mountains and that is important to me.
Lead Driver
Joined: Jul 2011
Posts: 8,679
Likes: 191
From: On the Edge of the Desert
Absolutely. 3.73-4.30 gears are best if you have overdrive. (and 29-33” tires)
MPG isn’t dependent on RPM. It’s dependent on engine load.
I recently went from 3.55 to 4.56 gears in my bronco. MPG DID NOT CHANGE! Even though I’m turning 500 more RPM at 65 mph.
MPG isn’t dependent on RPM. It’s dependent on engine load.
I recently went from 3.55 to 4.56 gears in my bronco. MPG DID NOT CHANGE! Even though I’m turning 500 more RPM at 65 mph.
Laughing Gas
Joined: Sep 2018
Posts: 1,223
Likes: 119
This is a good read for how they are related: https://x-engineer.org/automotive-en...sumption-bsfc/
Every engine has its own BSFC map. A big block with low end torque will do very well running low rpm highway cruising with overdrive. If you are pulling a heavy load it may be better to drop a gear and run the rpm higher if fuel consumption is a concern.
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