CJ7 - Opposite from everything you know

[Scramblur]

I have a 76 CJ I'm going to start on and had a thought. I want to do something that hasn't been done before. I'm thinking about taking this project in a completely different direction -

It will be
1. Super soft road ride.
2. Primarily focused on fuel economy and not horsepower. (engine and gear ratio?)
3. Quiet.
4. A proper grocery getter. In my case, a ride for my girl in a couple years when she turns 16.

I know this is opposite thinking from the typical RME discussions. What are your thoughts and suggestions for drivetrain and suspension?

 

[MikeGyver]

Turn it into a YJ.
My YJ is fun as hell to drive around town. Make sure it's got a manual trans and a fuel injected engine, otherwise you're wasting your time.

 

[RockMonkey]

Will it be 4WD?

 

[lewis]

Put a toyota drivetrain in it. That would be pretty different.

 

[RockMonkey]

Put a toyota drivetrain in it. That would be pretty different.

With stock WJ coils, shocks and links? I bet you could find that stuff for free-ish. You're clearly looking at a 4-cylinder something.

 

[jdub]

Leave it totally stock. Totally different and all of the above requirements are met.

 

[Chevycrew]

I vote for a 2010 camaro V6, small light and over 300hp. would get great economy with highway gears and a manual behind it.

 

[Scramblur]

Yes 4wd, to handle in the snow and a basic camping trip, but that's it. Would need to be high gear ratio. I don't think the yj is soft enough or fuel efficient enough. I like the Toyota option. Has anyone done a diesel in a cj yet? A small German diesel converted to run on recycled vegetable oil would be in the 40ish mpg I think.

 

[DaveB]

I'm in the middle of putting coils and long arms under my old commando and since the frames are meant for leafs stock tj coils work great. You can come by and see how I've done the suspension if you want.

 

[rholbrook]

4 cyl for better gas mileage? BS, my 2.5 ltr TJ gets the same mileage as my 4.0 ltr LJ. If you do use a 4 cyl, don't worry about a 5 spd because you'll never use 5th.

Drop a 5.3 ltr in it.

 

[SAMI]

I disagree rholbrook. A 4cyl diesel, or even gasser for that matter would be a great powerplant for a rig with stockish tires (31"s?). I especially love the idea of a 4cyl diesel on veg oil, I vote for that route. If you were to do a Toyota motor, i'd look at the 2.7 liter motor found in earlier Tacomas.

 

[JL Rockies]

2.8 VM Motori turbo diesel is hot effing jockma.

 

[N-Smooth]

pretty sure my 4.0L auto xj gets the same or better mileage than my 4cyl manual xj got... just saying. plus the 4 door is a bit heavier in stock form and i have added a lot of steel to it. also when i was looking at tj's years ago the 2.5 vs 4.0 mileage was within a couple mpg if iirc. there are other 4 cyl motors that get good mileage of course, but not jeeps

it would be neat to build something like that but i'm not sure a cj is the best platform. not trying to be a negative nora, just saying

 

[Greg]

My suggestions....

Suspension- Have a set of custom springs built by Alcan.- http://www.alcanspring.com/ Tell them your goal is a good riding Jeep. They will want to know EVERYTHING about your Jeep, so they know exactly how to build your springs. Read their FAQ/Tech page, probably a lot of answers to your questions- http://www.alcanspring.com/faqs.htm

Buy a high-quality set of shocks, something that is valved lightly, IMO. Some slightly taller than stock shackles should help the leafs work better and give a better ride.

You may want to consider a shackle reversal too, that will help the ride quality quite a bit.


Drivetrain- Mercedes OM617 turbo diesel engine, mated to a GM NV3500 and a NP231. Should return 25-30 MPG and have enough power to push a Jeep around. The engine is totally mechanical, making swapping and maintenance simple. Run something like 3.08 or 2.72 gears in the diffs to keep the RPM's down at speed and gain MPG. Depending on what year your CJ is, you may already have that gearing.

4x4 Labs has an adapter to bolt that Mercedes engine to any GM transmission. Obviously a manual will return better mileage, so that's what I'd run.

http://www.4x4labs.com/products/diesel-conversions/


It won't be totally quiet, but I don't think the Mercedes diesels are obnoxious like the older Dodge Cummins engines. Still, insulate the hood, firewall and fenders and I bet it would be fine. The only way you will see more than 20 MPG in a CJ, IMO, is a diesel.

Another diesel engine option would be a Cummins 3.3l, there are guys that have swapped one of these into a mid-sized SUV and are getting mileage #'s in the mid 30's!! :freak: Of course, those engines are pretty hard to find.

 

[UNSTUCK]

Turn it into a YJ.

Can we get this one deleted?

I vote for the TJ suspensoin and a 5.3L. You would never regret these moves. And if you ever wanted to make it more hard core, you'll be that much closer.

 

[Scramblur]

OK, I like Greg's idea with the Mercedes OM617.

Goal - 30MPG!

Where can I get one?

 

[Toad]

Yes diesels are cool. But they stink, noisy, and most if not all leave their mark everywere they go. Get a set of alcan springs. Follow the K.I.S.S method(keep it simple stupid). Get yourself a 4.8 or 5.3 gm hooked to a 700r4/4l60e with that overdrive trans and high axle gears you should easily get that into the 20 mpg range. Parts are cheap and easy to get. Call the guys at Novak they can get you everything you need to do the swap.

 

[JL Rockies]

The VM Motori is in all Jeeps in Europe and is available in the US since my Jeep has one under the hood.

Spark infestation should be avoided at all costs.

 

[Scramblur]

Toad I have a CJ8 with a factory engine with Mopar Fuel Injection and see 20mpg. This is just another Jeep... I'd honestly like to see 40mpg, but 30mpg is probably a good goal

 

[UNSTUCK]

I think that 5.3 would get you closer to 30 then 20. My old TPI 350 got 20 mpg with 35's and 4.88's. And while that 5.3 engine is not super rare in a Jeep, it is rare enough to get you tons of looks at a show and get lots of points for uniqueness.