Dumb Question 4wd vs 2wd MPG

[Steve Hunt]

Originally Posted by RememberTheFallen

Ah gotcha. That’s why I wasn’t even going to mess with these current 3.73 axles and try to sell them to someone with a diesel. I don’t trust myself to do a regear and shops charge an arm and a leg to do it around here. Was a lot cheaper for me to go with factory 4.30 axles if going 4wd.

I’ve never owned a 5.4 so no experience to offer but my V10 has 275/70-18 with 4:30 gears and I’m glad I didn’t choose to stick with the stock 373 axle. Timberline made a great find on low mileage full float factory 4:30, factory e-locker so the decision kinda of made itself. The 4:30 feels very good, no way I would go to the effort of changing it now but if I was doing it all over from the beginning I might ponder 4:56 harder.

[RememberTheFallen]

Originally Posted by Steve Hunt

I’ve never owned a 5.4 so no experience to offer but my V10 has 275/70-18 with 4:30 gears and I’m glad I didn’t choose to stick with the stock 373 axle. Timberline made a great find on low mileage full float factory 4:30, factory e-locker so the decision kinda of made itself. The 4:30 feels very good, no way I would go to the effort of changing it now but if I was doing it all over from the beginning I might ponder 4:56 harder.

Just checked and my good deal on axles is gone! Did you get them? Lol

That’s good to know. After hearing that others are at least using 3.73/5.4/33” combo it has me thinking about just using the low-ish (73k) mileage 2013 axles I have now and dealing with it until I can afford a regear and adding a locker. That would allow to go to 4.56s too. Chris at Ujoint said that is his preferred gearing for the 5.4 and 33’s.

This way I could split it into three steps. 1) hang 3.73 axles now and buy all the hookup stuff I don’t have (track bar, shocks, etc). And run it 2wd. 2) later on add the transfer case, driveshafts, cut tank, and modify trans to have full 4wd, and the lastly 3) regear and add rear locker/lsd with full size AT tires.

Decisions, decisions!

[loper]

OK, I started with a V10, 4:10 gears, and little 245/16 tires. Got 15 MPG driving to the shop to do the 4X4 swap.
Coming back with 4:88 gears and 35/17 tires I got 10 to 11 MPG.
The 5" lift, M/T tires, and roof rack didn't help...

[mikracer]

If you have everything to mount the front axle, I would just spend the time/money to install that and a rear block since you have it all. No need need spend money on a 2wd lift when you can do it with the parts you have.. You can run it as 2wd until you're ready to finish the 4x4 conversion (transfer case, shorten gas tank, shifter, etc.)

My V10 van got 12 mpg completely stock. With the 4x4 conversion, it dropped to 11. With the aluminess roof rack, it dropped the 10.

[b. rock]

Do the aftermarket tunes help with mpg any? I know sometimes factory tunes can be a little fat/rich in some of the highway load cells.

Don't forget tire weight, tread pattern, and compound. A heavy, thick, sticky, aggressive MT is going to roll far worse than a lighter, harder, milder AT.

I'd say overall vehicle weight is a factor too but for whatever reason the 2v mod motors don't seem to care about 1k lbs here or there. My V10 got the same mpg empty as it did loaded down, it was more speed + driving style that swung the needle from 9-13 mpg.

[1der]

Originally Posted by loper

OK, I started with a V10, 4:10 gears, and little 245/16 tires. Got 15 MPG driving to the shop to do the 4X4 swap.
Coming back with 4:88 gears and 35/17 tires I got 10 to 11 MPG.
The 5" lift, M/T tires, and roof rack didn't help...

Dang, physics.

[deserteagle56]

The van in my signature averaged 11.8 mpg over the last 60,000 miles since regear to 4.56. That figure comes from an Excel spreadsheet that figures in the odometer correction for the larger tires. And the tires are Toyo Open Country Mud Terrains, about the heaviest, stoutest tires you can buy.

[Obes]

I have been averaging 11 around town and about 13 on the highway. 2013 EB 5.4L, MG kit, NV271 tcase, 4.30 gearing in axles with e locker rear, 35" AT3's, 12' roof rack with 11.5' fiamma awning and road shower.

[DevineIntervention]

I’m getting 13.5 mpg around town with a 5.4, Cooper 285/70-17 (32.75” dia) tires, Weldtec Grocery Getter 5” lift, and 4:10 gearing. I saved a bunch of weight, avoided mechanical complexity, and retained good handling with keeping it 2WD. I added a locker for the tougher areas I head to for mountain biking. It’s certainly not 4WD capable, but it is capable enough for how I intend to use the van. I built this for what I do, not what the next owner might want to buy. I have an FJ Cruiser set up the same way. My neighbor has the V10 with 4WD and he is perfectly happy with his set up and 10 mpg. Mine’s the van in the middle, my neighbor with the red van has the V10.

[HIGHCOUNTRYMIKE]

Side Bar:
RememberTheFallen
I love your screen name
How soon we forget
Vet from VietNam I remember them every day
Thank you for the reminder
MPG
Speed is a key factor at 55 I get 20+ MPG
at 65 I get 15 MPG
at 70 I get 10 MPG
2003 EB350 SMB 4X4 7.3 292,00 heading for Sierra's tomorrow