Mr. Sandog

Well obviously not if you run 26" tires.

Tractionless

I would go with some 4.10 or 3.90 gears. They would reduce your ET the most without runing out of gear. Plus you gain mpg in the street with lower gears. (higher numerically).

edit: whoops I just saw your thread in the GM drivetrain. I was just lurking around in the mopar threads.... I was not spying....

FILE

iTrader: (5)

Most of us with a 1/2 ton truck owners don't run 32" tires. You will run out of gear soon with a 28-29" tires in 60+ mph rolls with 4.10's. I stand my ground my ground. Everything else equal, 3.73's will outshine 4.10's on high end pulls.

TigerFan187

iTrader: (1)

When I had the 4.8 I switched from a 3.42 to a 4.10 gear and I gained about 1.5mpg. That was on stock wheels and 1/2 highway and 1/2 city driving everyday about 35 miles a day. I lost a tad up top on the highway but I made up with that with the LS1 even on 20's. Im getting a Eaton put in Friday hopefully and I had to fight myself not to get 4.56's. I take one trip a year so Im not worried about it.

Mr. Sandog

There are so many factors at work here....

- What transmission is being run (auto, manual, 4L60E, 4L80E)
- What diameter of tires
- What diameter of wheels (24's take more to get going than 16's/17's/20's)
- What portion of driving is done in stop-and-go traffic
- What portion of driving is done on 40-45 mph connecting roads
- What portion of driving is done at 65-70 mph freeway
- What portion of driving is done at 75-80 mph freeway

And we haven't even gotten to the goals of the driver. Does the driver only care about speed and acceleration at the expense of everything else (e.g. moregrip), or do they care about mileage only (a few of us here), or a mixture of mileage and performance (e.g. me)? All of these things must be factored into the equation and decision.

One thing is beyond argument - if you want to get maximum gas mileage, you need to be running between 1800-2000 RPM's, which is the sweet spot for gas mileage efficiency for LS1-based motors. If this is what you are after, then choose your gearing accordingly to give you that RPM at your preferred speed.

moregrip

iTrader: (8)

there's some good advice, pick your combination to fit your goal.

moregrip

iTrader: (8)

I was referencing 4.10's to my combo(or 32" tires), and 3.90's to an assumed smaller tire diameter.

I still don't follow your logic exactly. Sure a 3.73 will pull a higher mph but is that top speed really going to make a difference at highway speeds? which to me, would be 100mph and less.
Maybe more people are racing around faster than 100mph than I realize, although I haven't seen it.

could you explain this to me as I may be missing the point here?

Tractionless

Go 4.10s or 3.90s. They give the most gains in ET, but if you street race most of the time go 3.73s. My 2¢

Tractionless

I think Tib means higher gears (lower numerically) work better from a roll since the tranny stays in the powerband of 2nd gears longer while trucks with lower gears shift into third earlier and stop pulling.

For example: My truck has 3.42s. At WOT it shift @ 6000 rpm around 92mph in 2nd gear. My brothers truck has 4.10 and shifts into third alot sooner. (8X mph) My truck stays at high rpms (engine produces more power) while my brothers truck shift into 3rd and the rpms drop and his truck stops pulling as hard. Both trucks with stock converter.

moregrip

iTrader: (8)

fwiw, I have recently owned two trucks with 30.5" tires. One with 3.73's and one with 4.10's. In any test of acceleration from a dead stop or at freeway speed the 4.10's won out, everytime.

Now, at freeway cruising speeds, the 3.73's were slightly nicer due to the lower rpm @ 70-80mph.