Ecodiesel on the Dyno. 3.73s with 37s

[TheSolarWizard]

Skip forward to 7:50

Sponsored

 

[jwalt]

Same hp and a 20ftlb torque loss both on the lower end with the way heavier teraflex wheels and 37s. 22-24mpg. Excited for the Gladiator diesel. Thanks for the heads up to forward to 7:50, sometimes he just likes to hear himself talk about nothing.

 

[RedTRex]

Cool, thanks for posting

 

[Schreconjeep]

Good info. Still thinking I’ll go with 4:10s since I can get them from a JL/JT take-off.

 

[WXman]

That torque is WAYYYYYYY low, or, the transmission is showing terrible amounts of parasitic loss. One of the two.

 

[dogbones]

Good info. Still thinking I’ll go with 4:10s since I can get them from a JL/JT take-off.

How easy are the 4.10’s to get?

 

[Schreconjeep]

They are around.

 

[enjin]

I was considering putting something like a 4.56 on there or something. Do you think 4.10 would be enough?

 

[Schreconjeep]

I think there is some math that needs to be done here to see what 37s do to effective drive train power to wheels compared to stock and how much 4.10, 4.56, etc correct that. I just don't know how that all works out.

 

[TheSolarWizard]

3.73 / 33 = X / 37 or whatever tire you want to run

 

[dogbones]

So thats 4.18. Wonder what real world feels like with the different trans and the diesel.

 

[TheSolarWizard]

So thats 4.18. Wonder what real world feels like with the different trans and the diesel.

adam from rock krawler told me that for the 38/13.50/20s on beadlocks they have on the JL 3.0D, he wished he had done 4.56 not the 4.10s they opted for. Someone on the JL forum did 4.56 and loved it on 37s but said it was a little short in switching to 40s.

Given those two statements I’m gonna say if you’re intending to run beadlocks or tow with 37s that 4.56 is probably the ticket. If lighter 37s and less or no towing is your thing, 4.10 is probably just fine

 

[WXman]

3.73 / 33 = X / 37 or whatever tire you want to run

This equation is good, but it assumes that 3.73 is the proper ratio for 33" tires, which it isn't. I think Jeep was trying to throw enthusiasts a bone here because Jeepers think they need the deepest axle gears possible, but throughout history diesel 4x4s have always come with numerically lower gearing in the axles to match the power band properly and even with the 2020s in the Ram guys are finding that the 3.21 ratio is much better for smoothness, MPG, and overall performance.

3.73s would be fine on 37" tires in a Jeep, but stock Rubicons will find 3.73s to be a bit overkill. Going to shift a lot and rarely ever use 1st gear unless you're really crawling.

 

[Just-Me]

I was considering putting something like a 4.56 on there or something. Do you think 4.10 would be enough?

What size tires are you planning? I'd say the gear calculator spits out 4.56-4.88 for 37's.

 

[Blade1668]

I was considering putting something like a 4.56 on there or something. Do you think 4.10 would be enough?

Out of my lane..... I re-geared my XJ from 3:55 to 4:56 and tire size change from 27 to 33, that put speedomete r on with "35s" slightly under with 33's MPG wasn't my big priority just off-road performance but I did enjoy fair MPG and towing compared to what it was.
But this is a apples to tomatoes comparison. Gas vs Diesel - old tech 4.0 gas vs new tech diesel at that. So a lot of people are just grasping in the wind without knowing the whole program. But I seem to remember diesel engines running with slightly taller gears than gas due to power curve, rpm range and peak power. Best thing might be talking with some diesel shops that are doing diesel tuning.

Sponsored