Just like the title says...
http://www.jeffsjeepyard.com/jeep-photo-gallery/jeep-photos.php?GalleryJeepId=4
http://www.jeffsjeepyard.com/jeep-photo-gallery/jeep-photos.php?GalleryJeepId=4
4BT Cummins Jeep Wrangler JK
- Thread starter Jorsn
- Start date
FreeManDan
Adventurer
Is there a state where you can get away with this? How is it street and obamissions legal? We don't all live in wyoming or the north west territory...
I am not sure I would get too excited about this. I have a tendancy to believe this:
A note on "4B-T Cummins"
... Regarding the 4B-T Cummins engines (aka UPS truck or bread truck engines), these engines were NEVER designed nor intended for use in passenger cars. Extreme vibration, noise, excessive weight, and poor fuel economy are the results. Consequently, the vehicle's overall driveability is greatly diminished. Generally speaking, our customers are people wanting better fuel economy and lower operating costs, so we feel the "bread truck" approach completely defeats the purpose of a diesel conversion. At Diesel Toyz, we only use OEM passenger car diesel engines that are chassis-specific to your vehicle. Take a look at our site to determine if a conversion is right for you.
http://www.dieseltoyz.com/conversions.html
A note on "4B-T Cummins"
... Regarding the 4B-T Cummins engines (aka UPS truck or bread truck engines), these engines were NEVER designed nor intended for use in passenger cars. Extreme vibration, noise, excessive weight, and poor fuel economy are the results. Consequently, the vehicle's overall driveability is greatly diminished. Generally speaking, our customers are people wanting better fuel economy and lower operating costs, so we feel the "bread truck" approach completely defeats the purpose of a diesel conversion. At Diesel Toyz, we only use OEM passenger car diesel engines that are chassis-specific to your vehicle. Take a look at our site to determine if a conversion is right for you.
http://www.dieseltoyz.com/conversions.html
Herbie
Rendezvous Conspirator
Even in California a diesel swap CAN be legal, but a 4BT would have to go into a similar chassis, i.e. if the engine comes from an HD chassis, it has to go back into one, so no swapping into a JK. I believe this is true in many states.
Obviously they are going to say this... They are in the business of selling VM Motori engines. If you own a Ferrari dealership you aren't going to tell someone to go next door and buy a Lamborghini. You should go over to the 4BT conversions forum and tell this to everyone.
4Rescue
Expedition Leader
They're legal and somehwat prevelent in Oregon... and most of the NW for that matter. Just one more reason to move to the best country in America 
they ARE a rough engine, but my buddy's 4BT FJ40 is perfectly plesent to drive on the roads and it's a BEAST on the trails. The motor mounts and soundeadening are KEY to makeing these trucks livable IMO and they're opne place alot of folks tend to skimp in the name of "getting it on the road" ...
Cheers
Dave
they ARE a rough engine, but my buddy's 4BT FJ40 is perfectly plesent to drive on the roads and it's a BEAST on the trails. The motor mounts and soundeadening are KEY to makeing these trucks livable IMO and they're opne place alot of folks tend to skimp in the name of "getting it on the road" ...
Cheers
Dave
MuleShoer
Adventurer
4BT into a JK
I spent an hour on the phone with Jeff this morning. Very enthusiastic about his product,
There are differnt levels of 4bt's and they can be quite streetable,215hp and 400lbs of torgue. For those that remember the early 6BT's in the dodges we all know how "quite" they areunk03: Apparently Jeff has worked out the computer interface with the help of an MB electrical design engineer.
Myself and my business partner gave up on this idea a year ago because of the ECU interface issues on the drive by wire JK's so this is exciting for us
This is a serious conversion, 4BT + Raptor 700 transmission + adapters + custom harness and interface + several custom fabricated parts and a heap of know how. Oh and you will need at least a 3 inch lift to support the heavier platform. Per Jeff everything function afterward but the cruise control has to be replaced with an after market version that ties to a mechanical pedal. The claims on the mileage are 25+ up to 30+ depending on gearing tires etc.
Emisions now thats a whole nutter matter.
I worked through the details of converting my JKU and he is working up a quote so it will be interesting to see the results. I was preparing to go the Hemi route but with a $9-$13 k price tag for do it yourself i am anxious to see the cost comparison
I spent an hour on the phone with Jeff this morning. Very enthusiastic about his product,
There are differnt levels of 4bt's and they can be quite streetable,215hp and 400lbs of torgue. For those that remember the early 6BT's in the dodges we all know how "quite" they are
unk03: Apparently Jeff has worked out the computer interface with the help of an MB electrical design engineer.Myself and my business partner gave up on this idea a year ago because of the ECU interface issues on the drive by wire JK's so this is exciting for us
This is a serious conversion, 4BT + Raptor 700 transmission + adapters + custom harness and interface + several custom fabricated parts and a heap of know how. Oh and you will need at least a 3 inch lift to support the heavier platform. Per Jeff everything function afterward but the cruise control has to be replaced with an after market version that ties to a mechanical pedal. The claims on the mileage are 25+ up to 30+ depending on gearing tires etc.
Emisions now thats a whole nutter matter.
I worked through the details of converting my JKU and he is working up a quote so it will be interesting to see the results. I was preparing to go the Hemi route but with a $9-$13 k price tag for do it yourself i am anxious to see the cost comparison
^^Jeff is a very nice guy and is willing to answer any and all questions.
The great thing about the 4BT is they can be found for cheap. Same thing with the 700R trans. Not just that but the 4BT will last 300,000 miles if serviced correctly and the rebuild kit is only $750. You can save TONS of money if you get the DIY kit. I believe you can reuse the stock transfer case, Not positive. I would personally do RCV's, inner sleeves, outer sleeves, axle truss, c gussets for the front axle due to the extra weight. You can always add more power, atlas tc, d60's, ARB lockers later on. Here is what I find most impressive....
25mpg's X 22gallons = 550 miles
Now throw in the Long Ranger Auxiliary Tank which is 18 gallons...
25mpg's X 40gallons = 1,000 miles:Wow1:
Want to get even more crazy?? I always keep two Rotopax 4 gallon packs with me...
25mpg's X 48gallons = 1,200 miles:Wow1::Wow1:
^^ This would be GREAT for overlanding.
Remember... They are getting 25mpgs with 5.13 gears and 40" tires!! If you're running 35s or 37s and 4.88s then you should be able to achieve 30mpgs at 65mph or 70mph.
The great thing about the 4BT is they can be found for cheap. Same thing with the 700R trans. Not just that but the 4BT will last 300,000 miles if serviced correctly and the rebuild kit is only $750. You can save TONS of money if you get the DIY kit. I believe you can reuse the stock transfer case, Not positive. I would personally do RCV's, inner sleeves, outer sleeves, axle truss, c gussets for the front axle due to the extra weight. You can always add more power, atlas tc, d60's, ARB lockers later on. Here is what I find most impressive....
25mpg's X 22gallons = 550 miles
Now throw in the Long Ranger Auxiliary Tank which is 18 gallons...
25mpg's X 40gallons = 1,000 miles:Wow1:
Want to get even more crazy?? I always keep two Rotopax 4 gallon packs with me...
25mpg's X 48gallons = 1,200 miles:Wow1::Wow1:
^^ This would be GREAT for overlanding.
Remember... They are getting 25mpgs with 5.13 gears and 40" tires!! If you're running 35s or 37s and 4.88s then you should be able to achieve 30mpgs at 65mph or 70mph.
Last edited:
D
Deleted member 9101
Guest
Hell, I'd drop one in a vehicle if I had the money.
Frank
Explorer
Hell yeah, me too!
BTW, Indiana you can drive a tractor down the road, legally. A diesel JK should be no issue what so ever. :elkgrin:
bldeagle10
Explorer
here in arizona alot of counties dont have emissions so im pretty sure this would be legal as long as you arent in maricopa. if i moved out to wikenburg, prescott or flagstaff i dont think there would be a problem at all. if i had the money id do it.
I see claims like this all the time, but has anyone actually seen it? The factory CRD diesel Jeep Liberty gets what, like 26mpg hiway? And the Grand Cherokee 3.0 liter diesel only gets 23. Heck, a stock Dodge Cummins gets 18 on a good day. Is a bread truck engine in a heavy, boxy Jeep with big high-drag tires really going to get better mileage than a lighter, sleeker, factory engineered, stock diesel liberty?
are-you referring to this forum?
http://www.4btswaps.com/forum/archive/index.php/t-4045.html
http://www.4btswaps.com/forum/archive/index.php/t-17365.html
http://www.4btswaps.com/forum/archive/index.php/t-4010.html
This is my favorite, from the owner himself, who did the conversion in a FJ80:
The 4bt is a loud, heavy engine and may or may not be suitable as a daily driver depending on your tolerance for noise and shakiness.
http://forum.ih8mud.com/vehicles-tr...-1992-fj80-cummins-4bt-diesel-conversion.html
I am not really going to go through a conversion just to verify if that's right or wrong - but when you think at about objectively, from an engineering angle, what they say makes sense to me.
You don't have to be an engineer to see that this engine has never been developped to be used in regular cars/light duty trucks.
Heck, Scott has a Jeep with a factory diesel in it, and even that vibrate quite a bit...
Last edited:
No.
I have a diesel grand cherokee.
It now sounds like one of the 80s mercedes cars with a diesel. Jeep has almost 50k on it.
When new it was quieter but I knew it would get a bit louder as it broke in.
I think its factory mileage paper said 24mpg, mine is an 07.
I can routinely get that kind of mileage out of it but I live in east tn and don't see high speeds much. Lots of 2 lane 55mph stuff out here.
If something less aerodynamic can equal or beat my mileage then I applaud it.
But I somehow just expect 20mpg out of some of that stuff in the links.
My jeep is stock. I replaced the tires before this past winter, put the exact same thing back on it because I ran into them at a nice price and I was more interested in good winter handling on the roads than anything else because I need to show up at my job.
One thing about the 250hp and 400ft/lbs of torque is that my jeep only has 215hp and 374 ft/lbs of torque so those numbers are not bad at all.
My grand cherokee has the same tow rating the hemi v8 grand cherokees got so I am pretty comfy with stuff in that power range.
As far as the 4bt being even louder, I would expect it and be fine with it.
I have never been a big fan of super quiet stuff. I prefer to know something is working and gassers get exhaust systems while diesels should be heard a bit and turbos should certainly be heard.
It now sounds like one of the 80s mercedes cars with a diesel. Jeep has almost 50k on it.
When new it was quieter but I knew it would get a bit louder as it broke in.
I think its factory mileage paper said 24mpg, mine is an 07.
I can routinely get that kind of mileage out of it but I live in east tn and don't see high speeds much. Lots of 2 lane 55mph stuff out here.
If something less aerodynamic can equal or beat my mileage then I applaud it.
But I somehow just expect 20mpg out of some of that stuff in the links.
My jeep is stock. I replaced the tires before this past winter, put the exact same thing back on it because I ran into them at a nice price and I was more interested in good winter handling on the roads than anything else because I need to show up at my job.
One thing about the 250hp and 400ft/lbs of torque is that my jeep only has 215hp and 374 ft/lbs of torque so those numbers are not bad at all.
My grand cherokee has the same tow rating the hemi v8 grand cherokees got so I am pretty comfy with stuff in that power range.
As far as the 4bt being even louder, I would expect it and be fine with it.
I have never been a big fan of super quiet stuff. I prefer to know something is working and gassers get exhaust systems while diesels should be heard a bit and turbos should certainly be heard.