Rear Gears - Summit vs. Richmond

[Vegas69]

This is a racing site now, nobody cares about gas mileage.

[Matt@BOS]

Originally Posted by Vegas69

This is a racing site now, nobody cares about gas mileage.

Dang, and that was usually my last excuse too. I could always brag that I got decent gas mileage driving to and from events.

Matt

[intocarss]

Originally Posted by Vegas69

This is a racing site now, nobody cares about gas mileage.

That's the smartest thing you've said all week

[billscamaros]

Originally Posted by GregWeld

So here's a more important question that which brand....


Have you done the calculations required to see exactly where you'd be with different ratios.

My experience is that you can drop ratio and get WORSE gas milage because you're too far out of the torque band of the engine/cam combo. This can happen with rear end gear change or a transmission gear change.

My "info" has always been that you want to be CRUISING at (pick a speed - 60 /65/70 mph) about 200 RPMS UNDER where your cam starts to make torque. Anything farther out than that and the motor is lugging - and wastes fuel.

There's a point at which the carb (air flow) is pulling in enough air and it get properly atomized etc... so it's not just all about rear gears.

Just talking out loud here. I'm no expert - but I have experienced the exact opposite of what I was trying to achieve!

Hey Greg .... no, I have to say that I haven't considered the gas mileage. The car is at a little over 3000 rpm at 60 ish, and all that I've thought about is dropping that to 2300 - 2500 rpm at that speed. That's interesting though ... I built the current motor a little over 10 years ago, so I'll have to dig thru the files to get the cam specs.

[Zspoiler]

I would n`t either. I have a 8.5 10 bolt in both my 1979 Z-28 Camaro (Supercharged Small block ,Super T-10 four speed) , 1981 El Camino SS ( 290 HP Crate engine ,Turbo 350 Trans) I run Factory GM 3:42 gears . Both cars have been my daily drivers at one time. Both cars run around 2500 rpm with a 26 tall tire. get around 20-24 MPG. The gears are very strong and are`n`t noisy. Like the Richmond gears .I got this recommendation from the owner of shop I had my 10 bolt rear end rebuilt at.