Best cruising rpm?

[Desertjr]

Trying to decide on 4.56s or 4.10s? 33x10.5, ax15, 4.2l mini stroker. 96 cam installed at 4* advanced with 1.7 roller rockers. Shooting for 65-70mph cruise. Daily driver main goal. Carries probably 1000lbs more than stock between the rack, bumper/winch & tire carrier & sliders & spares/tools.

4.56s give me around 2400rpm, the 4.10s give me 2150rpm, that's at 65mph. At 70mph its 2300rpm and 2560rpm respectively. What's your guys opinion?

[Desertjr]

Any advice? My estimated hp/trq is 310ftlbs from 2000-3600 rpm where it starts to tail off. Hp is around 125@2000rpm and peaks at 5000rpm. This is estimated. Sing desktop dyno.

To me it seems that since I've got my peak torque at or before 2000rpm I should run 4.10s? Lowest rpm with smallest throttle input = highest mileage? Is 2600+-rpm too much to cruise at on the highway?


I'm leaning to 4.56s..mainly because the added weight & wind resistances from the lift, tires & roof rack. I think it'll have a easier time chugging all that along with a extra few hundred rpm. And if anything I can make sure I stay around 65mog anyway. Unless anyone has good reason to go differently then. 4.56s it is.

[yuppiexj]

My lifted XJ ran 32" tires and 4.56 gears with the AW4 and stock 4.0

My mileage actually went up to 21/18, Until I flopped it on its side and totaled it.

This is not a Cummins with a 3200 red line. Let it spin a little bit.

[Desertjr]

Sounds like a plan. I figured it'll be easier to pull all the weight and push the extra wind resistance anyway

[Missourian]

I have a 4.6L Stroker in a 2000 Jeep Wrangler on 35's with 4.56's. I notice a huge increase in power and 4.10's would have been more than adequate for this set up.

[heavy equipment]

I just shift down. 55 mph in second gear doesn't go over 4000 RPM, 1000 RPM less than redline and I still pass other traffic while pulling a travel trailer up long, steep grades. The AW4 trans will go into lockup in any shift position when RPMs are high enough. This is good because it runs cooler that way due to less fluid friction.