Cummins Repower ISF 2.8 for Defenders

vintagepatina

Well-known member
im not sure where you get the impression that i'm wrong, but i can assure you that i'm not. overdrive gears are the weakest in the transmission. they are not designed for being driven at full load. pick any 5 speed light truck gearbox, even the exalted nv4500, and load it up in 5th and it will destroy it over time.
 

AdamSanta85

Well-known member
charming intellectual you are. but, it's obvious you dont know how a manual gearbox works. so move on.

What are you trying to accomplish here?

You have turned a reasonable question, if the R2.8 can provide an easy 75mph highway driving experience, into an solo argument about 5th gear strength.

Go pick a fight somewhere else.
 

vintagepatina

Well-known member
im not picking a fight. im exploring your performance expectations and discussing what might work/not work. in other words, exactly on topic.

even if a R2.8 will pull 65 to 75 in 5th gear, loaded, in 3 seconds flat you shouldnt do it because it will destroy the R380 putting that much torque through 5th. get it?
 

Red90

Well-known member
On a stock Defender, you need about 44 kW at the engine at 75 mph (120 km/h). The 2.8 will have around 88 kW available in 5th. Should be able to pull a 6% grade or so. The TDI is around 60 kW (in perfect condition) at that speed and can maybe manage a 2% grade.
 

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ezzzzzzz

Well-known member
im not picking a fight. im exploring your performance expectations and discussing what might work/not work. in other words, exactly on topic.

even if a R2.8 will pull 65 to 75 in 5th gear, loaded, in 3 seconds flat you shouldnt do it because it will destroy the R380 putting that much torque through 5th. get it?


While the 5th gear set is not as stout as the lower gears it is a mute point. The R2.2 will not produce the torque required to drive the vehicle at full load at 75mph up a good grade. EGT, if nothing else, will hinder the progression. The driver will inevitably have to downshift and move to the right lane to keep momentum.
 

Uncle Douglas

Well-known member
Callsign: delete
I'd dont get where this thread has gone. Where did not shifting come from ? Why ? How does maintaining a particular speed have anything to do with not shifting ? Fwiw sprinter's have a 6 speed auto and if operating properly you shouldnt feel when it shifts.

I guess this talk of pulling grades depends on your definition of a grade. The Cummins makes its max torque @ down around 15-1600 rpm so yes it will be happy in top gear cruising.

Most interstates are limited to 6% with exceptions to 7% in mountain areas like Colorado.

John has shown the Cummins has the torque to pull a 6% grade but that depends on a myriad of things like tire height, weight, gearing etc. I stated several times the first truck we built was a purpose built off road machine. No I havent driven it 75 mph, I just dont want to go there. It has 12.5 x 35 directional mud terrain tires 4+ inches of lift and slinky suspension, full external cage etc, 4:10's with lockers etc. I have no doubt it will do 75. The Cummins gear ratio calculator showed the truck shifting into 6th gear around 88mph.
If you have climbed some of the Colorado passes on I70 you know some of those grades are 12 miles long. My 2000 F250 with a fairly modified 7.3 computer controled powerstroke doesnt pull those grades without shifting.

HP and torque specs for the current 3.0 liter diesel sprinter van that you guys are holding up as a litmus test are 188 hp, 325 lb-ft.

Those engines are Tier (2010 and up) 3 diesels. The Cummins 2.8 is still the desireable Tier 1 (pre 2004). Tier 2 was 2004-2010. These tiers are emissions standards required of manufacturers. Retrofiting a Tier 2 or 3 diesel into a defender would be daunting. I personally wouldn't want to retro fit anything that requires DEF.

Personally, I think these are awesome retrofit engines for defenders. Having gone back and forth with Dave Ashcroft he feels strongly that the latest itteration of his r380 stumpy with HD bearings will hold up well to the R2.8.
I hope so, he's building me three that are supposed to ready to ship Friday.
 

AdamSanta85

Well-known member
I stated several times the first truck we built was a purpose built off road machine. No I havent driven it 75 mph, I just dont want to go there. It has 12.5 x 35 directional mud terrain tires 4+ inches of lift and slinky suspension, full external cage etc, 4:10's with lockers etc. I have no doubt it will do 75. The Cummins gear ratio calculator showed the truck shifting into 6th gear around 88mph.

Thanks. On the next truck you do, if you get a chance to highway test it, can you report back about how it feels vs a Rover TDI?

I am not concerned about climbing grades, just keeping up with LI traffic on hot windy days without thinking about EGT's.
 

donb

Well-known member
I'd dont get where this thread has gone. Where did not shifting come from ? Why ? Fwiw sprinter's have a 6 speed auto and if operating properly you shouldnt feel when it shifts.

I guess this talk of pulling grades depends on your definition of a grade.

Most interstates are limited to 6% with exceptions to 7% in mountain areas like Colorado.

John has shown the Cummins has the torque to pull a 6% grade but that depends on a myriad of things like tire height, weight, gearing etc.
If you have climbed some of the Colorado passes on I70 you know some of those grades are 12 miles long. My 2000 F250 with a fairly modified 7.3 computer controled powerstroke doesnt pull those grades without shifting.

HP and torque specs for the current 3.0 liter diesel sprinter van that you guys are holding up as a litmus test are 188 hp, 325 lb-ft.

Those engines are Tier (2010 and up) 3 diesels. The Cummins is still the desireable Tier 1 (pre 2004). Tier 2 was 2004-2010. These tiers are emissions requirements required of manufacturers. Retrofiting a Tier 2 or 3 diesel into a defender would be daunting. I personally wouldn't want to retro fit anything that requires DEF.

Personally, I think these are awesome retrofit engines for defenders. Having gone back and forth with Dave Ashcroft he feels strongly that the latest itteration of his r380 with the short mainshaft and HD bearings will hold up well to the R2.8.
I hope so, he's building me three that are supposed to ready Friday.


My daily driver is a 2015 Duramax. Loaded with ski gear and people that thing will pull up grades in Vermont like no other vehicle I've driven. Towing my 110 was nothing for it. It's freaking nice until it broke a couple of times this year and it's off to the dealer and a week+ wait for parts. I'm not sure I'd like to own it with some age and miles on the drivetrain.



I never knew about the different Tiers of diesel engines - thanks for that info.


Great news on the HD shorty R380. I'll be interested to hear how that works out.


I feel that if you have a LR that was imported as a diesel and you need more power and have the funds this makes a lot of sense. It's probably me being paranoid but what if you have a 2.5NA, converted it to a gas powered LS now, then years down the road the government wouldn't let you swap back to diesel? Not saying it will happen for sure and I read about gas to diesel swaps all the time but...
 

Uncle Douglas

Well-known member
Callsign: delete
Thanks. On the next truck you do, if you get a chance to highway test it, can you report back about how it feels vs a Rover TDI?

I am not concerned about climbing grades, just keeping up with LI traffic on hot windy days without thinking about EGT's.

There is no comparison to the rover tdi. It is somewhat disappointing the owner of the first truck doesn't have the time to come on the forums and shout out how happy he is with the engine. In way of endorsement, he's bought a diesel lhd white 110 out of France that I just picked up @ port of Baltimore last week and it is one of the three Cummins builds with r380's we have going now. Another is a lhd 90 from Italy for a female exec @ Microsoft who intends to do a blog as she drives it back to Seattle from Virginia's Blue Ridge Mountains. Third is a rhd SA 110 with galvanized chassis going to Wisconsin. All will have the new 380's with Ashcrofts upgraded 1.2 transfercases (sleeved and HD cross pin).


From my experience on the LIE, a 2.8 in a 90 would be fun for a couple days but then I'd have to move.
 

rocky

NAS-ROW Addict
There is no comparison to the rover tdi. It is somewhat disappointing the owner of the first truck doesn't have the time to come on the forums and shout out how happy he is with the engine.

I'm with you on the lack of actual owner feedback as well. Surely they didn't park the trucks and forget? Getting and giving feedback both bad and good is really valuable. No feedback is frustrating.
 

Uncle Douglas

Well-known member
Callsign: delete
Surely they didn't park the trucks and forget? Getting and giving feedback both bad and good is really valuable. No feedback is frustrating.

No, as I said he's bought another defender for us to convert. Is there a more enthusiastic /glowing endorsement ?
 

Red90

Well-known member
Having gone back and forth with Dave Ashcroft he feels strongly that the latest iteration of his r380 stumpy with HD bearings will hold up well to the R2.8.

But there is this anonymous guy on the internet and he says it will explode in 5 minutes. Apparently he drives in 4th gear and uses 5th only when coasting downhill with a tailwind. Stay tuned to find out who knows more about gearbox strength.

Power and torque should be on par with a tuned TD5 and there are thousands of them running around. I have this little suspicion that Dave might actually have some facts behind what he is stating.

What are you planning for a clutch?
 

brdhmltn

Well-known member
Having gone back and forth with Dave Ashcroft he feels strongly that the latest itteration of his r380 stumpy with HD bearings will hold up well to the R2.8.
I hope so, he's building me three that are supposed to ready to ship Friday.


Mine should be ready late this week or early next week as well. I?ll be more close to a stock setup. R380, stock 3.54 axles. Planning to start with 1.2 lt230 and go from there.

I?ll be waiting on adapters from axis at that point.

Do you know if Dave was only considering the base tune of the R2.8? There is the 200hp tune and they already have talked about a third tune later this year.


Sent from my iPhone using Tapatalk
 

Uncle Douglas

Well-known member
Callsign: delete
Brittany @ Cummins told me we are pretty much maxed out due to the hardware, ie upping the tune isn't likely to get more out of the engine without changing injectors, turbo etc. She indicated @ this point the tune changes are intended to improve emissions, efficiency, and engine life.

IMO no real need for more diesel in a defender. If I was building a 145 that I intended to run heavily laden or tow 10k with regularly then I'd choose a different engine like an LS.
 
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