I have a 2008 unlimited, auto with 3:73 gears. I recently upgraded slightly to a 33" tire. I felt a significant loss of power. I got a small amount back with the addition of the True fFow XDI, and the MBRP catback. Now, I drive my jeep about 80% on the freeway for work. If I was to add 4:88 gears would it be horrible? Would I be getting like 10 miles to the gallon? I dont want to be at 3000 rpm. Would it be tolerable with 33's for now till I get 35's next year? The reason I ask, is because I am sick of the constant downshifting when I hit a small incline.

 

back when I was running 33's I didnt notice this problem.. had similar set up auto, 3.73's on a 4 dr.

maybe try the superchips.. I noticed a good improvement in power with it.

 

I definitely thought of that. Its much cheaper than regearing.

 

Check out the chart in the Drivetrain FAQ's...

Auto - 4.88's - 33" tires @ 70 mph = 2400rpm

But, plug in the 'actual' height of your tires to get a better indication. (guessing your 33's are closer to 32", so adjust accordingly) I was running 5.13's with 32" actual height tires for a while. I wasn't happy with OD/off towing, but OD/on was just fine.

 

You are right. They are just a hair over 32". I might try the flashpack first then get the gears, see how I feel.

 

No one out there with 33's and gear swap with info. Most all the info I found is with 35's.

 

So the key is to stay in the green area for more of a daily driver and still decent mpg

 

I'm running 37s with 5.38s & auto . . and that chart looks about right. I know its off topic, but - no regrets with the regear. 16-19 mpg, as a daily driver - 40 miles one way to work.

 

I can't envision that ANY programmer is going to give you the boost that regearing will. The problem with ALL programmers is they give you the significant power gains at the high end. Regearing gives you the power along the entire torque curve. Unless you drive around most of the time with your tach in the yellow/red, you won't feel much benefit from ANY programmer. Consider your own example of 70 mph: 2400 rpm. Compare the torque curves of a stock JK and a reprogrammed JK at those low RPMs and you'll see that the torque increase is marginal at best. Now, if you want to get the Flashpaq in addition to regearing, well, that's a decision of whether you think the small gain is worth the expense. But, NO programmer is ever going to replace the need for regearing--the Jeep engineers are not that dumb that they left that much HP/torque laying on the design floor.

That's my humble opinion. YMMV.

 

While the bigger horsepower gains of a programmer (speaking of the Superchips) are certainly at the higher rpms, the most significant gains for a daily driver come in the lower end torque, and at lower rpms. The biggest torque gains occur in the 15-2500 rpm range and torque is the hammer to make your vehicle go. Horsepower on the other hand is what keeps you going.

So when looking at gears, if you aren't making a 2 set jump, a Flashpaq is going to bring you more. As most people are looking at a 3 set jump or more, the adage is definitely true, but it's not a clean blanket statement that gears will bring you more than a programmer.