Hi there new to this I have a p38 2.5 dt manual that I am hopping to put a cummins conversion does anyone on here know if it can be done I know I can make engine fit I think my problem is going to be with gear box can I use my original box transfer box with a adapted bell housing or is there conversion kits available any help appreciated
300bhp/ton
Well-Known Member
Which Cummins, they make loads of engines.
300bhp/ton
Well-Known Member
I have no direct experience on either. But I know of both engines.
The 6BT (5.9) is very cool and as most know used in the Dodge Ram.
However I'd have to ask what are you trying to achieve? The 6BT weighs about 900lbs!!!! And will make the RR nose heavy, so arguably less good on or off road with such an engine.
The 4BT is also heavy all things considered and in most cases will not be offering the power or performance. It might outperform the BMW 2.5, but a BMW 3.0 litre is likely a much easier swap and would for all intensive purposes perform better.
In fact a good 4.6 RV8 is a nice engine in a p38 and you can always add a turbo for more performance.
Biggest issues will be electronics I suspect. The body control module and engine module talk to each other. So retaining the factory alarm system might pose a few issues, as might getting all the items to work as they should. I'm sure it is all possible, but probably well beyond my skill set.
I can't see the gearbox being any good with either engine. And maybe not the Borg Warner transfer box either. Axles and diffs will also be a weak spot, especially for the 6BT.
As said, it really depends on what you are trying to achieve with the project though.
The 6BT (5.9) is very cool and as most know used in the Dodge Ram.
However I'd have to ask what are you trying to achieve? The 6BT weighs about 900lbs!!!! And will make the RR nose heavy, so arguably less good on or off road with such an engine.
The 4BT is also heavy all things considered and in most cases will not be offering the power or performance. It might outperform the BMW 2.5, but a BMW 3.0 litre is likely a much easier swap and would for all intensive purposes perform better.
In fact a good 4.6 RV8 is a nice engine in a p38 and you can always add a turbo for more performance.
Biggest issues will be electronics I suspect. The body control module and engine module talk to each other. So retaining the factory alarm system might pose a few issues, as might getting all the items to work as they should. I'm sure it is all possible, but probably well beyond my skill set.
I can't see the gearbox being any good with either engine. And maybe not the Borg Warner transfer box either. Axles and diffs will also be a weak spot, especially for the 6BT.
As said, it really depends on what you are trying to achieve with the project though.
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weemac
Well-Known Member
Britannica Restorations (Canada) posted some stuff on YouTube earlier this year about a 4BT conversion. Think it's for a Defender but the logic will be the same. Might be worth a look as he weighs up the pros and cons and I reckon he knows what he's on about 
EDIT: No affiliation but as a fellow Northerner, I enjoy the Yorkshire wit
EDIT: No affiliation but as a fellow Northerner, I enjoy the Yorkshire wit
300bhp/ton
Well-Known Member
Is that the 4BT or the new 2.8 that they are offering as bolt in kit for the Jeep Wrangler? The 4BT is 3.9 litres and quite and old design and weighs a lot. The new 2.8 is more akin to the Td5/Puma engine. It's nice, but also will be similar performance levels to a Td5 or even the BMW 2.5 in the p38.
weemac
Well-Known Member
Apologies. It's the R2.8 Cummins. Food for thought for the OP.
300bhp/ton
Well-Known Member
A good vid I'm sure, but I think the 2.8 is in the region of $9000 USD. So you'd have to really want it. And only 161hp.
and then add another 5-6k for the other stuff needed
weemac
Well-Known Member
As I remember, that's basically his conclusion. Unless you've got dollar bills coming out yer bum 'ole, there really is no value in it.
300bhp/ton
Well-Known Member
Don't get me wrong, a Cummins swap is a pretty cool project. But I can't see it being cheap or quick to perform and lots potential pitfalls.
what kind of suspension modifications and break modification. Is that vehicle even rated for that much weight
Most LR vehicles are rated at 3.5t and yes P38 is through the whole range I am sure.
J
300bhp/ton
Well-Known Member
All LR's with a ladder chassis since the early 1980's have been rated at 3.5 tonne (3500kg) tow rating. At least for UK/EU markets. Brakes and suspension are likely fine for this and the trailer would need to be braked anyhow.
300bhp/ton
Well-Known Member
If you do a lot of heavy towing and as much of a fan I am of Land Rovers, maybe an American pickup would be a better bet longer term.
Some of the modern ones are rated between 11,000 - 16,000lbs (5000 - 7272kg) and are built to be able to handle this even at high altitude and steep inclines. The older trucks are generally just as capable too. Chevy, Ford and Dodge all offer diesels or you could look at LPG'ing a petrol one.
Some of the modern ones are rated between 11,000 - 16,000lbs (5000 - 7272kg) and are built to be able to handle this even at high altitude and steep inclines. The older trucks are generally just as capable too. Chevy, Ford and Dodge all offer diesels or you could look at LPG'ing a petrol one.
It is a thought but access to some marinas is limited and range rover is nimble enough thinking along lines of your first suggestion of the 3.0 BMW engine
Witch seems more viable for my needs and deep more cost effective do you know what power difference would be down this route your advice is very much appreciated
Witch seems more viable for my needs and deep more cost effective do you know what power difference would be down this route your advice is very much appreciated
300bhp/ton
Well-Known Member
The BMW 3.0 M57 was used in the Range Rover L322. As well as many BMW cars.
Stock power is pretty good and they are very tunable. Lots of people race them and you can buy stand alone ECU's for them (pricey though). However butchering something like an old 5 Series might be the cheapest way.
I think the lowest output for the 3.0 litre was around 177hp in the RR. Most applications are over 200hp and around 280hp was the highest offered stock from BMW.
https://en.wikipedia.org/wiki/BMW_M57
People have fitted these to Defenders and I'm sure I've seen some p38's online running them too. Certainly worth a Google.
Stock power is pretty good and they are very tunable. Lots of people race them and you can buy stand alone ECU's for them (pricey though). However butchering something like an old 5 Series might be the cheapest way.
I think the lowest output for the 3.0 litre was around 177hp in the RR. Most applications are over 200hp and around 280hp was the highest offered stock from BMW.
https://en.wikipedia.org/wiki/BMW_M57
People have fitted these to Defenders and I'm sure I've seen some p38's online running them too. Certainly worth a Google.
