Warn Hub Conversion

[4x4garage]

I have a friend that added that conversion and he is running 37s on his rubicon... I think he had 4.56 gears (not 100%)... He said the biggest thing he noticed was the GAS MILEAGE INCREASE... He said he noticed a serveral miles per gallon jump. I'm curious to see what you get.

[NAILER341]

woo hoo! its like christmas or something.
thank you, sir! they will be cherished.

[Old Fart]

It's a Leaf Sprang Thang Erik!

[mrblaine]

I have a friend that added that conversion and he is running 37s on his rubicon... I think he had 4.56 gears (not 100%)... He said the biggest thing he noticed was the GAS MILEAGE INCREASE... He said he noticed a serveral miles per gallon jump. I'm curious to see what you get.

Not true and not possible.

Think about it. If DC could improve the mileage just by disconnecting the front hubs, they would do it to improve their CAFE average and sell more Vipers or V-10 trucks.

[rick]

Yeah, this is a popular urban legend that stems from some SUVs on the road today sporting "full time" 4wd. Think about what is actually turning when you have the hubs locked in versus unlocked... a driveshaft, differential, and axle shafts. Not much energy required to rotate that stuff going down the road. In fact, I have seen no difference whatsoever on my CJ with the hubs locked versus unlocked. I tested this theory a few years ago when I ran a couple tanks through it with the hubs locked. Not enough difference to even notice.

[Black & Tan TJ]

Not true and not possible.

Think about it. If DC could improve the mileage just by disconnecting the front hubs, they would do it to improve their CAFE average and sell more Vipers or V-10 trucks.

Well back in the day when we (self & friends) all had lifted 3/4 ton pick-ups and V8's the one with the manual hubs did get better mileage. Mostly noticed on long highway runs though but for me I rather not have that stuff moving if it's not in use.

B&T TJ

[Dukes69]

When I disconnected my driveshaft for the trek to Moab, I gained about 1-2 mpg. We disconnected Tammy (Jeepgal's) driveshaft for the moab drive and she got something like 22-24 MPG on the trip. I guess becuase its not true for 2 people, it must not be true for me.


10 foot tall and bulletproof,
Chris Field

[mrblaine]

When I disconnected my driveshaft for the trek to Moab, I gained about 1-2 mpg. We disconnected Tammy (Jeepgal's) driveshaft for the moab drive and she got something like 22-24 MPG on the trip. I guess becuase its not true for 2 people, it must not be true for me.


10 foot tall and bulletproof,
Chris Field

My experience is not limited to 2. It's more likely in the neighborhood of 10 and nothing we've been able to do with the hub conversion has shown an increase in efficiency. Of course, no one puts the hub conversion on with little tires and stock rigs. That may have something to do with it.

You say you gained about 1-2, was it one or was it two? The reason I ask is the following. I loaned my diesel to my nephew for a trip to colorado. I asked that they keep track of the mileage for me.

At the first fill-up they reported a phenomenal 21 mpg on a truck that my previous best was 18.

The next tank full was down to 16, the next was 14, the next was back up to 17.

Slightly confused over the varied results, I questioned them as to how and whom filled the rig. Turns out, I was the only one who had the patience to trickle in the last 6 gallons of fuel from the first click off. They had taken turns amongst the 3 of them and varied when they quit filling the truck. Some dribbled longer than others, but none of them filled it until they could see fuel in the filler neck like I did. That meant there was at least a 6 gallon difference in what they considered full. Has a tendency to skew mileage results.

In the 03, I consistently put 31 gallons into the 28 gallon tank when the low fuel light first illuminates. I have put as much as 33 in when I drove it for awhile after the light came on.

So, how are you checking the level of the tank? If you can't see fuel in the neck, you have no idea how full it is, do you?

[JeepGal]

I was the one that was keeping track of the mileage, and doing the fill-up. I cant remember exactly what my average was, but it was pretty amazing...somewhere between 22-24. I only filled up to the point of auto shutoff. Chris ALWAYS tops it off...

[sarah]

When I disconnected my driveshaft for the trek to Moab, I gained about 1-2 mpg. We disconnected Tammy (Jeepgal's) driveshaft for the moab drive and she got something like 22-24 MPG on the trip. I guess becuase its not true for 2 people, it must not be true for me.


10 foot tall and bulletproof,
Chris Field

How fast did you guys drive?

Rick says on the other hand his Jeep gets pretty much the same mileage whether he's pulling a trailer or goin' solo.

[mrblaine]

When I disconnected my driveshaft for the trek to Moab, I gained about 1-2 mpg. We disconnected Tammy (Jeepgal's) driveshaft for the moab drive and she got something like 22-24 MPG on the trip. I guess becuase its not true for 2 people, it must not be true for me.


10 foot tall and bulletproof,
Chris Field

I've thought about this some more. You know what it's worth to me for Kat's TJ to get 22 mpg? 500 dollars. I'll spend half a grand for her rig to get that mileage. Or, show me how to do it and the half is yours. Motor has to stay, tranny has to stay, already has a hub conversion, basically it has to stay a modified TJ without cutting it up.

I've got my money up, where's yours?

[jmbrowning]

E-Z now...let's all play nice in Sarah and Rick's sandbox...

now, having said that, I'd pay twice that to double my gas mileage (the regear to 4.88's hurt...a lot, can't wait for these 33's to wear out so I can get 35's). I can't say exactly what I get now as the speedo is still substantially off (was right on at 4.10 and 33's).

Chris, are you sure the odometer was square on Tammy's Jeep when you got those measurements?

[blkTJ]

E-Z now...let's all play nice in Sarah and Rick's sandbox...

my thoughts exactly... now don't make me have Erik ban all you guys.

[4x4garage]

Ohh man what did I start? but seriously. I will ask him what exactly he is getting. He is a local mechanic at a dealership in So Cal and is not prone to tell tales. I too was surprised as was he even. With gas prices at over 2 bucks a gallon for the cheap stuff here, I would be happy with 2-3 MPG improvement.

If you drive 12,000 a year in your Jeep and get 12 MPG. At 2.25 per gallon your spending 2,250 a year on gas. Now you get 14 MPG, you spend 1,928 and at 15 MPG, 1,800. Hmmm not that bad... You pay for the conversion in 2-3 years depending on what you save.

If it is true I just talked myself into some more stuff for the Jeep. I wonder if I can get away with "Winning" something that expensive on eBay and the wife realizing what that really means?

[Dukes69]

Snip . . . blah blah blah . . . snip
So, how are you checking the level of the tank? If you can't see fuel in the neck, you have no idea how full it is, do you?

When gas/fuel comes out of the filler and onto the ground . . . Its full!