Engine Swap: Cummins R2.8

[BroncoManSam]

Another quick video:
https://www.youtube.com/watch?v=M2Psvz1y6PQ

Initial impressions:
The R2.8 is really smooth for a diesel and not as loud as I expected. There was no noticeable diesel smell just standing around listening to it idle. I had to get my nose right to the tail pipe to really smell it.

Driving around the neighborhood, its a little sluggish off the line, but the boost comes on quick and then it really pulls hard, even at low rpm. Below 2000rpm, this engine pulls better than my 351W did. I will say the transmission adapter added a lot of rotating weight which doesn't help the engine get up to speed. Overall driving was pleasant. One surprise was chirping the rear tires by getting out of the gas quickly. I tried it a few times just to be sure, but in low gears, the engine pulls down fast, maybe due to the throttle body in the intake.

I need to button up a few things tomorrow and double check everything is tight and leak free, then I'll go for a longer drive.

This is incredible. Thanks so much for sharing. I’m starting the process of putting the R2.8 in my ‘73, with the Tremec TR4050, so all this information you have here is invaluable, thank you. Can’t wait to see more videos and pictures.


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[904Bronco]

Congrats sir, no better feeling than turning that key and bringing a long build to Life.
May the long drive go as well as the one around the neighborhood.

Doug

 

[Digger556]

I drove the Bronco to work on Friday. Nothing eventful, but fuel consumption is noticeably lower than the 351. Based on the 1/4 tank I've burned so far, I'm getting roughly twice the range, putting me in the mid-20s for mileage around town. I'll need to burn a few tanks to get a solid number, but it's encouraging so far.

Here is a video from one of my test drives.
[youtube]UxqB25a_48I[/youtube]

https://www.youtube.com/watch?v=UxqB25a_48I

 

[ntsqd]

As a driver of diesels I know that they're hard to directly compare, but I'm going to ask you anyway. How does it compare in driving it? I saw the you mentioned the extra inertia in the flywheel assembly, I'm sure that reduces throttle response.

 

[LoneRanger]

Great write up, very well done!

L.R.

 

[Digger556]

As a driver of diesels I know that they're hard to directly compare, but I'm going to ask you anyway. How does it compare in driving it? I saw the you mentioned the extra inertia in the flywheel assembly, I'm sure that reduces throttle response.

It's been interesting. Definitely a little more sluggish right off idle than I expected, but give it a second and that boost comes on and it pulls hard.

I've adjusted my driving style to apply gas sooner and harder when letting the clutch out and that has negated the difference between the two engines. To be fair, the 351 was well built for power and was snappy off the line. The R2.8 would compare even better against a stock 302.

Overall drivability is great IMO. The truck, even with 37s, has no issue moving with traffic. Rolling down the road, you step on it and the turbo responds quickly and with 15-20 psi of boost, the Bronco gains speed fast, even in overdrive.

 

[71 CA Bronco]

Well done.

I'm not sure comparing a 351 is fair. Sounds like it just drives like a diesel. They have their purpose. I drove one for ten years. It always lumbered on take off then spooled up nicely. Bullet proof though. I drove it over 200k miles with virtually no maintenance other than oil changes. It made better mileage than my wife's Honda Pilot. I miss that truck. I should have never sold it.

 

[Digger556]

It's worth mentioning that I have maintained all the emission equipment and the stock tune. From my vantage in the driver's seat, looking at the tailpipe, I cannot see visible smoke when accelerating.

I imagine this engine is capable of snappier performance off idle at the expensive of emissions, but it is not tuned that way. You can tell the fuel rolls on more slowly than my 7.3 Powerstroke.

 

[EB70]

How's the MPG doing with this? I really appreciate your posting this.

 

[Digger556]

How's the MPG doing with this? I really appreciate your posting this.

I wish I could tell you, but I just haven't burned enough fuel to know for sure.

I dumped some fuel in it when I first fired the engine and burned about a 1/4 tank before filling it all the way. I've driven 400 miles but only 205 since I filled the tank. My estimate right now is 20-22 mpg driving a mix of interstate and stop-and-go traffic.

 

[Digger556]

Got my first mileage read today.

23 mpg driving a mix of 75 mph interstate and stop-n-go commuter traffic. I think that is respectable for a Bronco on 37s with 5" of lift

 

[markw]

That’s impressive!


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[marjama]

Love it - nice work! Congrats on getting it back on the road! I try not to look at your thread too often so I won't get the itch to do a 2.8 swap into anything. Yet.

 

[Digger556]

2 month update:

- Miles driven: ~4000

- Average tank: 23 mpg

- Worst tank: 22 mpg

- Best tank: 24.5 mpg

- First trip off road went real well. The Cummins is a solid performer on the trail. Good low end torque, feels unstallable in the rocks, runs 176-180F all day and sips fuel. Even on a 9 hour trail day, the Bronco still average 22 mpg on that tank. One of the best parts, it doesn't smell like a diesel. Both groups I led said they didn't smell the engine.
https://www.youtube.com/watch?v=w2IDZH6yXE0

- Towing the camper: The Cummins did better than expected. I was apprehensive that 161 HP would be enough to push two bricks down the road, but I could generally cruise at 65-70 mph, which is plenty fast around the mountains of Colorado. Not only was I able to keep up with traffic, on some hills I was even the one doing the passing.;D
Towing the camper would drop my F250's mileage from 20 to 13. With the Bronco, I was pulling a solid 17mpg. I was able to make a 500 mile trip on less than a tank and a half.
The bad news is on the really steep, long grades at full throttle, the cooling system is not quite keeping up. While the radiator could keep up with a 375HP V8, I think the additional heat load of the CAC is too much. Right now I'm focusing on improving the air flow through the radiator by plugging the gaps and improving the venting.

- Misc stuff: I've been putting the Bronco to work hauling equipment and removing trees. You know, for science. I won't be towing cars or anything, but it handles 3500 lbs without issue.

 

[JeffG]

Very impressive update. That engine will give you years of happiness.

 

[toddz69]

Very impressive, Digger! So cool to hear that after all your hard work that it's working so well.

Todd Z.

 

[Yeller]

I have a similar cooling issue caused by an air bubble from the bumper and winch blocking airflow. It mostly raises its head when it the ambient temps are high (95+) but I can slow from 75 to 60 and watch the temp drop. It doesn’t just shoot up, it slowly builds, takes 25-30 miles to get up to where I’m uncomfortable. I’m sure it’s from the height of the radiator to bumper and winch relationship. Not saying this is it just sharing experiences. Spectacular build and am glad you are happy with the outcome.

 

[Digger556]

Yeller, thanks for sharing your experience. I've been running around with the winch installed and I've been wondering if it was messing up my air flow. It worked fine with the V8, but again I have a CAC now. I had a similar experience after returning from my trip where I can watch the temp slowly rise at 75-80 mph over 20-30 miles. I dont remember it doing that before installing the winch.

I bought a digital manometer and have been taking measurements to baseline an improvements in airflow. It's probably worth pulling the winch and retesting.

 

[Yeller]

Mine is exaggerated, the winch/bumper is high and the radiator is mounted 3" lower to protect it if I do something dumb like put it on its lid.... and there is no skirting on the sides to force the air through the radiator. The trans cooler is in that spot as well, trans temp doesn't increase so that may be part of the equation of the cooling pack not performing well at higher interstate speeds. 65 and slower never seems to be an issue, fuel mileage is about 25% better too over 75 LOL

 

[EB70]

That is excellent news. It is on my radar for later to do that swap. Everybody says "who cares about mileage". I was that guy. Until I moved 50 miles from town.