Thinking of swapping in a 3.9 liter cummins 4 bt into my suburban. I saw a guy swap in a motor out of a sprinter van claiming 30 mpg around town. I have a big family so a rice burner is out anyways. It is paid for and the 350 is a gas hog. So I have been kicking around to do this or pick up a complete 6.5. I have seen a few places to pick up a adapter for cummins to chevy bell housings. Does anyone know on a 1999 if the tranny will have to have any special wiring to make this work? THANKS

Try this site: http://www.4btswaps.com

Nick

Thanks

I put one in our '95 burb with the 4L80. You'll have to work out connecting a throttle position sensor, and to get it to shift right you'll need to reprogram the trans.

What kind of mileage do you get? Either way the cummins has to be better than the stock 350.

Any new info on this thread, I to am possible interested in this swap I haven't decided.

I have looked at the cummins site above, and listened to the youtube videos. I am not sure on the 4bt, that thing sure sounds louder than I really would want. So I am thinking of either a 5.9 or just building up a pre'94 6.5 with the mechanical pump.

The adaptor to mount the 4bt to the chevy trans is about $950 on ebay and the cost of an average used 4bt engine is multifold higher than an average used 6.5 engine. You'd probably want to dump the electronic 4L80e auto and trade for a non-electronic diesel 700r auto. These are the biggies.

Still, the cool factor of having a 4tb is priceless. I'm looking to do this down the road.

A 4bt really isn't that loud. They sound a lot like the first gen 5.9 12 valves, which are the quietest of the 5.9 family, except for the common rail engines. There are a couple of guys on the 4bt swaps page that sell engines with adapters for around $2200. I know a guy in Ohio that sells them with adapter for $1700 and I can get you his info if you like. They are good runners and taken directly from bread trucks. A buddy purchased one and hasn't had any trouble with it. The adapter on the 4bt will bolt up to a 4L80E without any trouble. The only thing you will need to make the 4L80E work is a stand alone trans controller and a diesel torque converter.

Good luck with whatever direction you end up going. I'm planning on throwing a 4bt in a mid 80's 3/4 ton chevy so I can pick up some mileage commuting.

Kyle

My burb is paid for and by the time my wife finishes school and we replace it, it will have over 200K on the original everything. So rather than getting rid of it for cheap, I'm thinking of a project of some kind. We shall see.

30 mpg's in a Sub is hard to imagine but it would be awesome for sure.

30 mpg's in a Sub is hard to imagine but it would be awesome for sure.
It was in the last diesel power magazine. It only had like 180 hp. It isn't like he was looking for a ton of power,just more mpg's.

I haven't done a long run on mine running on diesel only, but I doubt mine will do much more than 25 mpg because it is a 3/4 ton w/4.10s. If you have a 4L80, keep it. It is tons better than a 700. All you have to do is give it a throttle position sensor and rpm input, and it works fine.

marcdeluca: Does it sound loud in the cab, or is the noise level elevated on the youtube videos?

Not a bad idea to refresh the trans while you are there. 4BT's have prodigious torque.

and they can be turned up just a little ;)

It was in the last diesel power magazine. It only had like 180 hp. It isn't like he was looking for a ton of power,just more mpg's.

Yeah I remember the article. I was surprised that the owner said it got 40 mpg. I think that a 30 mpg Sub would be awesome while 40 is unimaginable.

Yeah I remember the article. I was surprised that the owner said it got 40 mpg. I think that a 30 mpg Sub would be awesome while 40 is unimaginable.

40 sounds almost too good to be true.

30 is definately in reach though.

The 4BTs arent super loud. Just at idle, just like any other cummins.

Although if you have the time I would lay down some dynomat and insulations throughout the cab of the burb.

As for the trans, a standalone controller and diesel converter will get you rolling. As mentioned the throttle sensor and RPm input are the biggest hurdles.

a 6.5 would be cheaper and easier but wheres the fun in that.

plus you can get more power out of the 4BT safely. Theyre the same as the 6 but with 2 cylinders chopped off.

it is a 12v p-pumped engine with 2 less cylinders. The 12v 6BTA is a great engine. Try to get one that is already turbo'd. you can buy injectors cheap( $400 or less) and add another 60HP/120TQ