Overland owners who switched to 35 & 37 tires

[d k]

I'm sure you're already done this but just a rough calculation shows that going from a 32" tire to a 35" tire is about 10% taller.
So to keep the same gearing, going from a 3.73 to 10% shorter is right around 4.10
37" tire is around 15% taller, so to keep the same gearing you would need something around a 4.3 to keep the same overall gearing (feel).

With the horrible characteristics of the 3.6, I think going shorter with gearing is even better. So 4.56 with 35's and 4.88 with 37's is what I would shoot for.


As for the basics of setting up a differential, setting preload and backlash is still the same, even though the axles have some more advanced features.

I wish I was more competent with differentials so I could do it myself, but I would rather leave that to professionals.

I've thought of re-gearing so I could tow more comfortably, but then I haven't done the math to decide what gears IF I did, and no one around here does that work. I'm old school - if this was differentials from the 60s and 70s, even into the 80s, I'd think about doing it myself, but not with the complexities of these systems.
I have Rubicon springs up front which raised the Overland about 1" and max tow springs in back to better support the weight - that dropped the rear about 1/2" so I need to find some spacers for the thing to bring the back up again.
No plans on going bigger tires, but then never say never. Since it struggles now as it is, no way I'd ever consider towing with 35s and these Overland gears. Bad enough with the stock sizes.

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[d k]

On paper it might look good, but even though the torque curve is 'flat', it is still very low.
I believe the torque peak is 4800....wtf??

By comparison, the inline 4.0 peaked at 1500ish.

The 2.0 has much more torque off the bottom, where you will be spending most of the time crawling.
The problem with having low torque off the bottom is the necessity to spin the engine high. With traction being unpredictable and wheels coming off the ground, this is a recipe for snapping things.

Depends what you want to do with the truck. For crawling I think I would prefer the flat predictable torque of the 3.6 that sets in earlier even if it doesn't peak as high. Better control.

 

[ShadowsPapa]

On paper it might look good, but even though the torque curve is 'flat', it is still very low.
I believe the torque peak is 4800....wtf??

By comparison, the inline 4.0 peaked at 1500ish.

The 2.0 has much more torque off the bottom, where you will be spending most of the time crawling.
The problem with having low torque off the bottom is the necessity to spin the engine high. With traction being unpredictable and wheels coming off the ground, this is a recipe for snapping things.

LOL..... Hardly. The 4.0 for 1994 torque topped over 213 at 4000 rpm while hp topped out at 4800 rpm. (Depending on the vehicle - some charts show torque peak in the low 3,000's)

 

[d k]

What are you trying to say?

LOL hardly?

if you have something to say, say it.
stop being a passive aggressive.

not sure what your angle is on this but it is totally obvious that the engine characteristics of the 3.6 are not ideal for low speed rock climbing - the kind of driving most of us do in a Jeep.
It may make more power than the 4.0, sure but the characteristics of the 4.0 were way better. 3.6 makes way more power but it makes the power in the wrong area of the curve.

LOL..... Hardly. The 4.0 for 1994 torque topped over 213 at 4000 rpm while hp topped out at 4800 rpm. (Depending on the vehicle - some charts show torque peak in the low 3,000's)

 

[mtgustin]

What are you trying to say?

LOL hardly?

if you have something to say, say it.
stop being a passive aggressive.

not sure what your angle is on this but it is totally obvious that the engine characteristics of the 3.6 are not ideal for low speed rock climbing - the kind of driving most of us do in a Jeep.
It may make more power than the 4.0, sure but the characteristics of the 4.0 were way better. 3.6 makes way more power but it makes the power in the wrong area of the curve.

Remember that HP is at the crank...not the rear wheels....more like 220 more or less....

 

[HWKIGRL]

I have an overland with the 2” Mopar lift and 35” KO2s (E load) other than steering issue (that will be taken care of with new TSB..thank you Jeep!) I LOVE my JT!!
I do lots of mountain highway driving (I’m in So Cal) and it handles it fine.

 

[ShadowsPapa]

What are you trying to say?

LOL hardly?

if you have something to say, say it.
stop being a passive aggressive.

not sure what your angle is on this but it is totally obvious that the engine characteristics of the 3.6 are not ideal for low speed rock climbing - the kind of driving most of us do in a Jeep.
It may make more power than the 4.0, sure but the characteristics of the 4.0 were way better. 3.6 makes way more power but it makes the power in the wrong area of the curve.

You said the 4.0 torque drops off at "1500ish". I hope u were joking. It doesn't peak until double that. I said zero about the 3.6. Not a word about the 3.6. The 4.0 doesn't do as well under 2000. I have owned and built multiple I6 and 4.0 in particular.

 

[d k]

i said the 4.0 peaks - not drops off.

the point that I was trying to make is that our engine torque peaks at 4800 which is totally unsuitable.

I wasnt arguing about peak numbers and which makes more etc. just saying the 4.0 was more suitable in character than the 3.6, thats all.

Looking at the dyno graphs between the 3.6, 4.0 and even the 2.0, I believe the 2.0 is the more suitable engine for low speed off roading.

Others might have a different opinion, but if I was given the choice, I would without a doubt choose the 2.0 over the 3.6.
But, thats not an option, so this conversation is pretty much pointless.

You said the 4.0 torque drops off at "1500ish". I hope u were joking. It doesn't peak until double that. I said zero about the 3.6. Not a word about the 3.6. The 4.0 doesn't do as well under 2000. I have owned and built multiple I6 and 4.0 in particular.

 

[ShadowsPapa]

i said the 4.0 peaks - not drops off.

the point that I was trying to make is that our engine torque peaks at 4800 which is totally unsuitable.

I wasnt arguing about peak numbers and which makes more etc. just saying the 4.0 was more suitable in character than the 3.6, thats all.

Looking at the dyno graphs between the 3.6, 4.0 and even the 2.0, I believe the 2.0 is the more suitable engine for low speed off roading.

Others might have a different opinion, but if I was given the choice, I would without a doubt choose the 2.0 over the 3.6.
But, thats not an option, so this conversation is pretty much pointless.

It doesn't even peak that low. I could dig up dyno results. It's a rather sharp line up past 2000 even to 3000. But it doesnt matter as its not current and the diesel would be better than either. So yeah it's moot. The 3.0 sounds interesting.

 

[WK2JT]

Sure, the 4.0 was a decent power characteristic engine, that’s an I6 for you. Would be great to have a modern day version. However, the 2.0 turbo is worse than any of them. Its torque curve lags the 3.6 by about 600 RPM... that’s the characteristics of a small displacement 4 cylinder turbo engine. I know a couple of guys with the 2.0 that bought it because it made more peak torque than the 3.6. They both also hate the 2.0 now due to the turbo/torque lag.

 

[j.o.y.ride]

Friends don't let friends induce turbo lag.

I have had plenty of small displacement turbos. On the road where things spool freely meh. Even big turbo replacements are ok because they are free wheeling.

In situations where you want to hold and maneuver slowly and in a controlled manner the flat torque of the V6 is better imo. Who cares if peak on the V6 is 4800 its basically the same from 2500.

The turbo has a narrow band from 3500-4500 where it's flat. before that and after that it's changing.

For stable toque bands you get a 1,000 rpm band on the turbo that takes spooling to get into and 2,300 rpm band on the V6 that eases in.

I know which I will take. If you want the turbo have at it.

Also this thread has literally NOTHING to do with I4 vs V6.

 

[WK2JT]

Friends don't let friends induce turbo lag.

I have had plenty of small displacement turbos. On the road where things spool freely meh. Even big turbo replacements are ok because they are free wheeling.

In situations where you want to hold and maneuver slowly and in a controlled manner the flat torque of the V6 is better imo. Who cares if peak on the V6 is 4800 its basically the same from 2500.

The turbo has a narrow band from 3500-4500 where it's flat. before that and after that it's changing.

For stable toque bands you get a 1,000 rpm band on the turbo that takes spooling to get into and 2,300 rpm band on the V6 that eases in.

I know which I will take. If you want the turbo have at it.

Also this thread has literally NOTHING to do with I4 vs V6.

Yeah, completely agree and thought about the topic drift when I was posting. Back to 37” rubber! Lol

 

[d k]

So from 2700 to 5700 the turbo makes more tq than the 3.6 and it's a worse engine?

I'm not arguing, I'm more or less curious as to the thinking behind it.
Modern turbos don't have lag and don't any lag.

Friends don't let friends induce turbo lag.

I have had plenty of small displacement turbos. On the road where things spool freely meh. Even big turbo replacements are ok because they are free wheeling.

In situations where you want to hold and maneuver slowly and in a controlled manner the flat torque of the V6 is better imo. Who cares if peak on the V6 is 4800 its basically the same from 2500.

The turbo has a narrow band from 3500-4500 where it's flat. before that and after that it's changing.

For stable toque bands you get a 1,000 rpm band on the turbo that takes spooling to get into and 2,300 rpm band on the V6 that eases in.

I know which I will take. If you want the turbo have at it.

Also this thread has literally NOTHING to do with I4 vs V6.

 

[j.o.y.ride]

So from 2700 to 5700 the turbo makes more tq than the 3.6 and it's a worse engine?

Huh? Who said that it's a worse engine?

Anyhow I'm done discussing the merits of the 2.0 and 3.6 in this thread that's actually about 35" or 37" tires.

 

[d k]

Sounds good to me.

this thread that's actually about 35" or 37" tires.

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