Gearing question for c6

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Sep 10, 2004 | 05:09 PM

MatthewC

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From: Fredericton NB, Canada

Gearing question for c6

I currently have a set of 31's with stock 3.55 gears. I will soon be getting a set of 33s on 15x10 rims. I know that a set of 4.10's would fit the bill, for some get up and go while still maintaining a decent top end, (maybe a sep of 3.90, 4.0's??) But my question is how my 3 speed auto c6 would affect that. Should I be looking at gears like 3.90's or something around there is im doing mild highway driving? I would like to have decent rpms on the highway while still having some giddy-up in the cuty (where most of my driving is done). Am I making any sense??

-Matt

Sep 11, 2004 | 09:18 AM

jowilker

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From: Creedmoor, North Carolina

Matt, The C6 like all other non overdrive trannys has a 1 to 1 output. Tis your tire size and rear ratio that effects pulling power and mpgs.

Slower turning engines make better mpg
Faster turning engines make better pull
At the the same mph

John

Sep 11, 2004 | 10:18 AM

Robb Harding

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With the taller tires, your 4.10 gears should fit the bill for all around use.
(Unless you have overdrive, everything is a compromise.)
As far as the C-6 trans. is concerned, I suggest going to a wide ratio
set-up for better low-end grunt. When I had my trans. rebuilt, I opted
for the 2.72 low gear, in lieu of the stock 2.46, and find the engine gets
into the proper mid-range torque curve faster and easier when towing or
hauling heavier loads.

Sep 11, 2004 | 11:26 AM

MatthewC

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From: Fredericton NB, Canada

Yeah, ive noticed that it runs like a 20 year old Labrador even with 31's and 3.55's. Gas mileage sucks . If I were to put the gears in now, before getting the 33's, would that REALLY compromise highway use?

-Matt

Sep 11, 2004 | 11:50 AM

Robb Harding

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Matt:

Switching to the wide ratio trans. gear set will not affect hwy. mileage.
As mentioned prev., non-o/d trans. always yield 1:1 in high gear.
What WILL change is your CITY mileage. (for the better) A lower
1st gear enables the mtr. to get all that mass moving w/ less effort.
(read less gas consumption) Unless you are into drag racing,(in which
case, close ratio gears are desired) the w/r gears work great for "haul-
ing". Cost is approx. $130. more than the stock planetary gear set.

Robb

Sep 11, 2004 | 12:43 PM

MatthewC

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From: Fredericton NB, Canada

And just to verify, front and rear gears MUST be of the same ratio?

-Matt

Sep 11, 2004 | 01:47 PM

Robb Harding

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Absolutely-----and just to elaborate on axle gears; be aware, those
taller tires are going to result in a higher effective ratio; in the 3.80-3.90 range, with your 4.10 differential. This could yield a little more gas mileage
due to lower rpm's, but that will likely be negated by the larger rolling mass and aggressive tread that is inherent in off-road tires. (If you want to get
more scientific about this, there is a site w/charts/formulas, etc. I am
sure someone can jump in and direct you.)
One can go on and on about gearing cause a lot of things factor into it.
I see you are still on-line so will stay here a few minutes if you have more
questions.