Auto Hub to Manual Hub conversion

[Texafornian]

It has a NP229-AT t-case. No QT.

[J20 project]

Wow 26 mpg w a hemi and 35s? You from Texas or Montana?lol. No I know the answer to that


J20

[Texafornian]

I'm actually from San Diego California. Hahaha. Was transplanted here in 2000. I miss my mountains. Hahaha. Anyway, the truck had help. Manual hubs, electric cooling fan, K&N cold air intake, Borla cat back exhaust, 45 psi in the tires for trips, and a removeable tuner. It didn't hurt that I tend to have a soft foot and use the cruise control quite a bit.

[Tinkerjeep]

Going from parasitic drag in a front axle to no drag/no rtating parts will theortically gain you SOME mileage increase, but at highways speeds, its not likely.

The reasons your 08 Dodge got "better" mileage...(I have a hard time believing 26 is accurate with a lift, 35s at highway speeds - I think your speedo sending unit is not corrected for the tires) is likely because of three things:

1) electronic engine management and a modern, efficient V8 engine versus a carbed engine engineered 40 years ago.
2) more gears in the tranny.
3) better aerodynamics. the windshield rake on modern Dodges and the rounded front fenders is way better at sliding through 75mph air than the 40 degree windshield rake and square front end of a Gwag./ Jtruck.

I've heard of guys getting better mileage (maybe 10%) from running locking hubs and a Part Time kit versus running a Fulltime QT with front drivetrain engaged and pulling all the time. I never noticed any gains. I got 8mpg with a Mile Marker PT kit, then I got 8mpg with the fulltime QT restored. I had 31" tires and 3.73:1 then, and now I have 32-33 inch tires and 3.73:1. and I have verified my speedometer with a radar gun/readout so it is within 1MPH. I get around 8-9mpg now. That's all city/rural at 30-45mph. with some 55-65mph on the Highway, I get around 10+.

[goldhammer]

I get about 12.25 around town and 14 on the freeway at 65 with the cherk, but it is a 4 speed, 3.31's and 31-10.5's You might see a small difference in your favor, but the AT is going to suck the mileage no matter what you do. Most of the AT's around here average 10mpg.

Like the Lincoln MK4 in the parade last w/e I saw...sign on the door----"low mileage vehicle-3 gallons to the mile"

[crazydog]

Going from parasitic drag in a front axle to no drag/no rtating parts will theortically gain you SOME mileage increase, but at highways speeds, its not likely.

The reasons your 08 Dodge got "better" mileage...(I have a hard time believing 26 is accurate with a lift, 35s at highway speeds - I think your speedo sending unit is not corrected for the tires) is likely because of three things:

1) electronic engine management and a modern, efficient V8 engine versus a carbed engine engineered 40 years ago.
2) more gears in the tranny.
3) better aerodynamics. the windshield rake on modern Dodges and the rounded front fenders is way better at sliding through 75mph air than the 40 degree windshield rake and square front end of a Gwag./ Jtruck.

I've heard of guys getting better mileage (maybe 10%) from running locking hubs and a Part Time kit versus running a Fulltime QT with front drivetrain engaged and pulling all the time. I never noticed any gains. I got 8mpg with a Mile Marker PT kit, then I got 8mpg with the fulltime QT restored. I had 31" tires and 3.73:1 then, and now I have 32-33 inch tires and 3.73:1. and I have verified my speedometer with a radar gun/readout so it is within 1MPH. I get around 8-9mpg now. That's all city/rural at 30-45mph. with some 55-65mph on the Highway, I get around 10+.

If you go back and read his post, he states his figure is coming from the overhead. These are notorious for being wrong. He also says he has a programmer on the pickup. These will make the readings far less accurate, regardless if he has corrected the computer for larger diameter tires. But, he also thinks wagoneers need to have track bars.

[Texafornian]

Honest injun, my speedo was corrected and the inboard GPS verified through distance travelled, on the Dodge, that is. I totally realize that the Jeep is far too boxy and made out of real metal to accomplish the same results as the Dodge did.

Let me clarify myself. I don't believe there is any way, except possibly a diesel conversion, to get 20 mpg or higher on the freeway. That would just be fantasy. However, I am currently of the thought that I should be able to reach somewhere around 15 mpg all around environment driving. Now, I'm not claiming this will be easy or inexpensive. Here is what I plan to do as a full process in order to try and achieve it:

Use Royal Purple synthetic engine oil
Use RP synthetic gear oil in both diffs
Use RP synthetic trans fluid in trans and t-case
Install manual locking hubs
Install aluminum radiator with electric cooling fan. Remove engine driven fan and clutch
Replace wheel bearings and lube with quality synthetic grease
Install headers, no cat, and single 3" tube to Magna Flow/Borla muffler
Install HEI ignition including distributor
Install, at least, a TBI
Install a modified snorkel or K&N cold air intake
Install a RV cam in the motor, eventually I'll put the big money into the motor
Drive with a soft foot and use cruise on the highway
Inflate tires to 40-45 psi
Use Water Wetter in the cooling system

To me, and my past experience with playing around with this kind of thing, I think 15 mpg is reasonable.

[Tinkerjeep]

Ristow routinely got 15 in his Cherokee Chief I believe.

Its not so much about fluid changes as it is what transmission you use and carb jetting. He does admirably well with the Holley 1850s.

I'd look him up before you go spending hundreds on full synth oils and chasing a few % points from running twin electric fans, which add load to the Alt.

[Tinkerjeep]

Honest injun, my speedo was corrected and the inboard GPS verified through distance travelled, on the Dodge, that is. I totally realize that the Jeep is far too boxy and made out of real metal to accomplish the same results as the Dodge did..

GPS isn't accurate either. Garmin puts my house more than 200 yards away from where it actually is.

Google earth is routinely wrong.

IIRC GPS uses cheapy low bandwidth satellite signals, the units I'm familiar with are not known for accuracy.

You can time a mile at indicated 60mph on any highway as long as its flat and likely get good numbers and go from that. Mile marker to mile marker in exactly 60 seconds will be 60mph. Do it three-four times to see if your getting consistent data.

I've heard of the onboard computer Speedos being 10% off from the factories.

[Ristow]

was 14's routinely. it did very low 15's a couple times. not after the 3.73 axles,sidepipes and bigger tires tho.

[Tinkerjeep]

Allright, I misremembered. But YOUR Jeeps are among the few modded ones I can put on a list that haven't been boogered with and still get good mileage without throwing a bunch of expensive magical parts at them.


FSJunkie's Wag is fairly stock for a 1972 Wag IIRC and he claims decent mileage too.

[Texafornian]

Perhaps I need to be more transparent, or perhaps less cryptic is a better choice. I'm not putting goodies on my Jeep in order to get decent mileage. I'm putting the things on, that I've mentioned, because that's my rendition of building a better moustrap. Lol.

I bought this Jeep because I love the style, the function, and the capability that can be wrung from the vehicle. Thanks to this purchase, I no longer have a truck payment. Woohoo!. That's dollars I can put in the Jeep and not raise the ire of the wife. Haha.

I wanted to take an older Jeep that fits my size and lifestyle, and make it as modern as possible while avoiding complicated computers, weird systems and sensors that affect unrelated systems, and a few other pet peeves. I'm probably like a bunch of you, I enjoy being different. I want no part of the herd. I'm always being talked to everywhere I go, because someone has a past experience that warms their heart, makes them smile, or even brings a tear to the eye. I've had this SJ a month and a half, I've already met like 2 dozen people, in person, because they want to talk about my Jeep. Personally, I think this is cool and I enjoy it.

Increasing fuel mileage is a desired side effect of my project of building this Jeep. My primary reason is to have fun, making my Jeep my way. I couldn't care less about resale, etc. This Jeep will be my ride until dino fuel is is no more, or I end up wheeling in the after-life. Lol.

My plans are extensive, and I'll never save enough fuel, or make enough money to justify what I'm going to do. It sure will be fun, and it will be ALL mine. Here are my plans for now. I haven't resolved the engine/transmission question yet, because I'm still thinking, reading, and asking questions.

My GW: 6" SOA lift, rear will be adjusted so the Jeep is level. Modified kicker shocks or torsion bars, dual front stabilizers, QD's for front sway bar, rear sway bar with QD's, dual shocked front, single shocked rear (probably King shocks), 4.10 - 4.56 gearing (dependant on final tire size decision), ARB Air Lockers, Wilwood two piston brake calipers and lines (have already converted to rear discs), manual locking hubs, upgraded drive shafts, 17x9 or 17x10 aluminum wheels with 4" backspacing, 33-35" MT tires, tire liners, Bushwacker pocket style fender flares, rear bumper with tire, jack, and fuel can mounts (line-x'd), line-x'd roof with safari basket roof rack (possibly an ARB rack with the roof mounted tent, line-x the roof rack), Warn "Trans4mer" front winch mount with grill and brush guards, Warn winch, LED driving lights and a front mounted LED light bar (reason for dual shocking the front), billet grill if I can find someone to make it (if not, I'll just paint the stock one), convert to LED or HID headlamps, convert turn signals to LED (hopefully will be able to find clear lenses), convert side marker lamps to include turn signals, LED tailights and a backup light, better mirrors (going to try early to mid 80's Bronco mirrors that swivel out of the way), HEI ignition system w/distributor, aluminum radiator with electric fan w/in cab control, HD steering box, 200 amp or larger alternator, serpentine belt conversion, dual battery arrangement, aluminum hi-flow water pump, TBI, snorkel, headers (stainless ceramic coated, stainless tubing, no catalytic, Magna Flow or Borla muffler), upgraded steering shaft, oil pan w/skid plate, correct potential oil starvation issue, urethane bushings in all suspension and body locations, skid plates for Tcase, transmission, and possibly the diff's, new motor and trans mounts, new trans and engine oil coolers, oil filter relocation with dual filters, line-x the interior floor, relocate interior floor wiring harnesses into protective conduits and add connectors so can be easily accessed for repair if nec, replace all interior panels with aluminum that will be powder coated and sound insulated (including the interior roof), replace seats (probably with high end Recarro seats), relocate drivers seat rearward (need more leg room hahaha), modernize the dash display (not sure if I'll go with the Dakota conversion or individual gauges that actually tell you something and are truthful. Lol), remove rear seat (don't need it), install custom false floor from rear passenger area back to tailgate (front section will house amplifiers and subwoofers, rear part will house large pull out drawer that is sectional for carrying tools, recovery gear, camping gear, etc.), custom made floor and celing consoles that will house Ham Radio, CB Radio, GPS, interior lights, and dvd player/screen (for those late nights out camping when I can't sleep)(I'm also considering mobile Direct TV so I can still go wheeling during football season. Hahahahaha), limo tint all rear windows and darken front driver and passenger windows, powdercoat all shiny trim (or paint if it can't be pc'd), install secondary fuel tank where stock spare goes - if I can, am also looking into installing custom fresh water bladders in between the body and interior panels, replace stock fuel tank and modernize fuel feed system, and a possible 1-2" body lift (only if necessary), combination rock sliders and steps, line-x lower body and front bumper, paint the beast, install full roll cage (padded, too Expletive Deleted!Expletive Deleted!Expletive Deleted!Expletive Deleted! old to be banging head, knees, elbows, etc. Lol), install LED off road lights up top, and I guess that's about it.

Rough estimate, I figure it will take me about 5 years to accomplish. I'm thinking between $25 - $30k in expense. That's about $5k - $6k average per year. My last truck payment was $5.4k per year (I usually paid more @ $6k a year). So, in the long run, I will have a totally awesome, thoroughly custom, classic and completely functional 4x4. I find this much more pleasing than paying over $30k for a modern 4x4 (which don't fit me anyway), and then having to do a whole bunch of that customizing anyway. That's where I am coming from.

PS. I might have missed a few items, here or there, what can I say?