ya can't use a rear diff in the front.

I can't say I don't like the cummins, it would be purpose built is all. either ecconomy or play. I guess ya get an atlas t-case with 5 gear ranges, or a 4:1 doubler and run 3.08 gears with a nv4500

the thing weighs 700# and makes  a mild 105 hp and 265 ft/lbs of torque under 2000rpm.
hows that compare to a 4.0? 190hp and 230ft/lbs 450#'s...
other than mileage, hardly worth it to me.
I've seen claims of 180hp and just under 400ft/lbs from the 4bt also with the pumps set up that high I'm sure the mileage isn't so sweet.

I'm putting a gm6.5td in a cj. it weighs 780# and stock came up to 215hp @3200 and 440ft/lbs @1800rpm.
a chip in the 96-99's can make 300hp and 550ft/lbs..
nice power for a jeep with 4.56 gears and 33-35" tires and a nv4500. (65mph just above peak torque)
my 98 burb can get 20mpg's depending on how it gets driven and is just over 7300#'s, in the 4000# jeep it would do quite well. my rubi weighs 4500# with me and my minimal gear. the best part is it shares engine mounts and bell housings with the sbc's.

6500's, 250-300hp, enhanced 6.5 diesels are being used by the US Government for the 6ton armored HMMWV.

another engine I'd be interested in for late model/emmisions legal swaps is the the new 07 grand cherokee 3.0. 215hp @3800 and 376ft/lbs from 1800-2600rpm in stock trim.

one of the forum members here has a 4bt... I think 4btme is the screen name, haven't seen a post from em in a while, I'll send em an e-mail to ruffle feathers and get someone who know more about the cummins and has first hand experience...

remember the VW cappa was sending praises?
a super/turbo charged 2.0 gasoline that has charactoristics of an electric motor... now thats what we all really want!


.............................  

Well how would you feel about a B3.3T.  I know it has even less horsepower but if I put some better injectors and a better turbo and intercooler the numbers should be around 140ish.  I know that's not a lot but I have the four-banger and lots of things look better than it.  The torque is a lot more.  I know the 4.0l is good but after you get to the wheels the hp is about 130 and the torque goes down a bit.  The 3.3 also gets great gas mileage which is one of the main reasons I have been thinking about this.  Even with the four banger, I only get 21 on the highway (about 19-20 if there is wind) and am lucky to get 14 in town (on a good day).  So I'm in a quandary -_-'  

"...gas mileage which is one of the main reasons I have been thinking about this."

Today, the average price of unleaded in Phoenix is $3.60, and diesel is $4.10.

If you get 15 mpg on regular, that is .24 cents per mile. If you got 20 mpg on diesel, that is .21 cents per mile.

If you drive 12,000 miles per year, that is $360 per year in savings.

If you spent $3000 converting to a diesel engine, it would take 8 years and 4 months to break even. And that would not include your time.

So, if you like diesels, and you like working on cars, and you considerer it a hobby, well hobbies cost money.

But, a main reason for doing an engine conversion being fuel economy, doesn't make financial sense.  

Ok.  Well diesel here is $4.23.  The 3.3l cummins gets at the lowest, 30 mpg.  That is .14 cents per mile.  My jeep gets 20 mpg and that is .20 cents per mile.  That is $720 dollars savings.  I hear most people get 35 or so that is .12 cents per mile which makes $920 dollars a year.  Why does anybody do an engine swap?  The need more hp and torque and gas mileage is a plus.  If I have a four-cylinder that gets 21 on a good day and a little rav 4 can get 29 on it's four-cylinder, that is lame in my opinion.  I'm just saying the increase in mileage is a huge plus coupled with more power.  

I got an e-mail back from 4bt4me... he has limited i-net access. anyhow I got a number for him, post up any specific questions about the 4bt an I'll see what I can find out....  

I was using your city mpg number and your statement as mpg being one of the main reasons for doing the conversion...

There's nothing wrong hobbies or realistic expectaions.  

Here is some diesel mpg info. Click here.  

Ok.  Sorry if it seemed like I was irritated at you.  Well, I have been doing some research and the new crd 3.3l cummins is pretty awesome.  I read about a guy who did a swap in his YJ and got in the low thirties and high twenties in mileage and it has 110 hp and 304 ft-lbs. of torque and it weighs about one hundred or so pounds more than the 4.0l.  I really like that engine because it is smaller and I wouldn't have to get a body lift or anything like that (I hope at least).  Also, I can get an aftermarket turbo and intercooler on it and it can get the hp up quite a bit.  I will probably try to get that one I think.  Plus, the new crd has a computer applicator that adjusts the power curves and whatnot depending on what work or type of driving is necessary (agricultural to highway...).  

I'm not trying to be irritating, and I'm not even trying to give an opinion. All I'm trying to do is provide some facts and data.

It seems that most would agree that diesel is 20-30 percent more efficient than gasoline. But, when you compare identical vehicles that were optioned with either gas or diesel, the diesel option doesn't come close to obtaining a 30% increase in fuel economy. The diesel is closer to a 15-20 percent increase.

These numbers are based on EPA ratings which are very liberal. So liberal in fact, that the EPA methods of calculating fuel economy, will be changing in order to produce a more "real world" estimate.

My number crunching assumed a liberal increase of 30% (15mpg to 20mpg) for your YJ. I used the city mpg because I figured you probably do more city driving than freeway driving. Again, trying to be realistic in my attempt to give you facts and data.

Most people don't acheive the EPA estimates because they can't, won't, don't drive conservatively enough. And certainly someone who is interested in turbos and more power would probably also fall into the group of EPA mpg underachievers.  

Hey mud,

Are you speaking of the m1114 hmmv or the m1151 hmmv. Both are heavy. Ive personally been on and in the 1114. Never in the motor though. They were dogs for 16500#'s. (not suprised) We ended up cranking up the mechanical pump and opening up the exhaust. We also ditched the 500 cfm air filters for the no canister versions. Ive not seen the 1151 up close and personal. So im interested in the one you are referring too. Is the injection mechanical or electronic? I have yet to have the opritunity to attend the am general course. I need to knock on wood or they will voluntold me for a years worth of ojt with them.

Turbo feeding a supercharger. In that respect Ill stick to the 8v92.  

the new 07+ 6500 versions for the 6t armored.

IDK what the military stayed with after 94. 92-93 were the only years the mechanical was used on the civilian 6.5's, 97 they pretty much rid em of problems and aftermarket chips started making some power with em.