Help with Gears
Thread Starter
JK Enthusiast
Joined: Apr 2008
Posts: 305
Likes: 0
From: Austin, TX
Yes that is in OD. Your auto has a .69 overdrive ratio which makes a huge difference. The old 3 speed autos where top gear was 1:1 could never run a ratio lke this. MY JK with 35" KM2's and 5.13's runs 2600 (very close to the 2571 mentioned above) and I really Think that is the sweet spot on the engine. Now keep in mind that is at 75mph; if you were going slower, say 60 or 65, your rpm would be lower. With 4.10's or 4.56's your rpm would probably we too far below where this engine makes it's torque.
With 33's and 4.56's you would see 1922 at 60 and 2082 at 65.
With 33's and 4.88's you would see 2057 at 60 and 2228 at 65.
There is a lot to think about when mking the choice as to what gear to choose. At it's cost most of us can't afford to make a mistake.
You might want to pay attention to your rpm when towing at various speeds with the OD off. For instance with 33's and your 3.73 stock ratio and OD off (so no .69 OD but 1:1) you would spin 2278 at 60 and 2468 at 65. Of course I don't recall whether or not you already had the 33's.
As a further aside, and to further confuse the issue, with your 33" tires and 5.13 gears and in OD you would see 2162 at 60 and 2347 at 65.
Confused yet?
With 33's and 4.56's you would see 1922 at 60 and 2082 at 65.
With 33's and 4.88's you would see 2057 at 60 and 2228 at 65.
There is a lot to think about when mking the choice as to what gear to choose. At it's cost most of us can't afford to make a mistake.
You might want to pay attention to your rpm when towing at various speeds with the OD off. For instance with 33's and your 3.73 stock ratio and OD off (so no .69 OD but 1:1) you would spin 2278 at 60 and 2468 at 65. Of course I don't recall whether or not you already had the 33's.
As a further aside, and to further confuse the issue, with your 33" tires and 5.13 gears and in OD you would see 2162 at 60 and 2347 at 65.
Confused yet?
After that I'll strap on a supercharger and will be good to go.
JK Super Freak
Joined: May 2008
Posts: 1,279
Likes: 0
From: Grand Junction, CO
You might want to look at my new post "Just did Hypertech Speedo Calibrator and MPG results" where I did the speedo correction and the results in mpg with the 35's and 5.13's and the comparison to stock.