Cutman

I've added some weight to my JK with steel wheels, bumper and a roof rack. I habe the 3.21 gears and was wondering if a tuner would make any difference at all with get up and go? Changing shift points?

karls10jk

For the manuals it just pulls the lag out of the pedal (or did on my 2010). I bounce between "tunes" but I can't say I notice a real difference- except for the mileage tune, that one kills your acceleration. I couldn't stick with it long enough to determine if it actually helped my mileage.

Trail Jeeps

It'll help a little. It's a cheap mod for the couple of extra ponies you squeeze from it.

If you really want to wake it up, try and find some good take off 3.73 gears from a Sahara and have a shop install them. It'll feel like you've added 50 horsepower.

Cutman

That was going to be my next approach. I was wondering if it would make that much of a difference.

nthinuf

From a quick glance at the rpm chart in the faq's, going from 3.21 to 3.73 should add a little over 300 rpm @ 70mph.

300 rpm might give, what, a few hp? 2? 3? And the tuner companies say they give around 20+/- hp, but that is way up at 5-6k rpm. Probably more like 5-6 hp down where most of us will normally be. So a tuner, (plus premium gas), plus a regear (plus the $1600 +/- price tag), gets you less than 10 hp for normal driving.

A little food for thought while you continue researching it ...

Ryan0260

Re-gearing is not going to give you any more hp, but it will put the engine in its power band which is going to allow it to operate efficiently and give you as much hp and torque as it is going to produce with the stock motor. It definitely will feel like it has a lot more hp, and is by far the best mod you can do besides forced induction or a motor swap as far as performance.

austin160

I just regeared from 3.21 to 4.88 for 37's. Do yourself a favor and get rid of the 3.21. They are only good for delivering the mail.