How it does this new Juiced up 2024 second gen l5p Duramax diesel engine tow with a load behind it. Well, today we’re going to find [ Applause, ], [, Music, ] out welcome back to the channel guys, I’m Alex. We got this 2024 Duramax with us and we have our 14,000lb trailer setup hooked up to this truck we’re ready to tow my 120 m Loop. This second gen l5p got a little bit of a bump and power, we’re now putting out 470 horsepower as well as 975 LBT of torque, and I’m pretty excited to see if this Duramax can now give the old Power Stroke a run for its money. As I mentioned last week, this updated Duramax has a new fueling system, updated pistons, and it’s now giving this engine a Max towing capacity of 21,600 lb in a crew cab 4×4 configuration up from 18,200 lb, so a pretty significant jump in towing capacities with this updated Duramax, as per usual with our 14,000lb trailer, we use the exact same trailer same load, same load, location, giving us the same tongue weight roughly 1,400 lb.
We also Drive the exact same 120, Mi Towing Loop, ideally giving us a very good comparison between truck and engine. Well, we got this V8 rumbl in here and she is thirsty for some miles so we’ll get this thing on the road first off, however, we’re going to do our offline acceleration test see how well this truck pulls a load from a standstill honestly, First Impressions, it Feels very very similar to the first gen l5p Duramax. I honestly can’t notice too much of a difference. Another thing I’m noticing right off the bat here is the exhaust brake. I mean it’s fully on it’s.
I guess it’s better, but it’s just still not in the realm of that common engine. Now, speaking of acceleration test, I’m excited to do with this truck because well, this has a 10-speed Allison Transmission that can fully lock up the torque converter in first gear, hopefully giving this truck a really nice launch off the line, we’re going to go 0 to 50 Km an hour put her in four-wheel drive and just see what she’s got 3 2 1 to the floor. 50 km an hour. Take two 3 2 1 to the floor. Oh yeah!
She definitely has some freaking B to her in first gear. It’S time for our acceleration test getting up to speed on the highway, we’ll go 60 km an hour to 110, roughly 70 mph 60 km an hour to to the floor. Oh yeah, 110. There we go and we’ll see where that time ranks you guys will know where it ranks um, but unfortunately I don’t not yet all right. We got a little bit of a different camera setup today.
Let me know what you guys think, but my prediction for our Towing run today with the 66 durmax um. I’M really excited to see how the exhaust brake performs looking forward to that. Secondly, um I just like I touched on earlier in the video I feel like this Duramax is going to struggle a little bit with that low-end torque um. So I think we might see a little bit more downshifting than something like the cumin, although the cumin only has a six-speed transmission. So it’s a little bit of a comparison, apples and oranges, but that’s my prediction.
I think the Duramax may not be able to keep up to something like the power stroke that has a purposely extended stroke to gain that lowend torque, but uh. Only time will tell now that right there is a little bit of a load. If I do save Zone myself, woo look at that thing. What do we got pulling this? Oh good old, Kenworth, all right?
Oh, how dare I a freaking Peter Built our first h on the Loop, not very steep, but it’s pretty darn long and while we’re revving at 1,800 RPM, which is actually a lot lower than I would have predicted with this Duramax like to see it um. For example, with the 66 gas engine I told a couple weeks ago, we were at like 3500 RPM on this exact stretch of road with the same load, obviously um. So this thex is making very quick work of this trailer. I mean even the comons with that massive download Torque was only Reven at like 1600 RPM didn’t even shift gears. This thing seems to have not shifted gears either, which is pretty impressive.
Again, I thought for sure we were going to have to downshift but uh. This thing just keeps on trucking a couple weeks ago I tow with the 6.6 L gas engine with the 10-speed Allis and transmission. Like I’ve mentioned a couple times, and I said that that engine was now in real competition with the 6.6 L Duramax.
I stand by it um. You know that engine is now pushing or able to tow up to like 18,600 lb, which is truly in desel engine territory, but towing with the diesel is such a GameChanger. It is night and day it’s just so much easier. You guys saw when we were going up that hill. This thing was like 2,000, less RPM, it’s not going to drink as much fuel.
It just makes your life so much easier. So if you’re, okay, with fronting a little bit extra money and having a more maintenance cost on the diesel, it’ll make your life so much easier. When towing and speaking of fuel economy we’re averaging 21.4 L per 100 km, which is about 11 m per gallon and well, the power stroke finished our course. With 12.
m per gallon, the cummin finished with 11
9, So currently we’re a little bit behind there, but we’ll have to check in at the end of our course and see those numbers. But what I want to talk about and continue our discussion about gas vers diesel, the 6.6 L gaser engine was sitting at like 7 miles per gallon or roughly like 32 33 lers per 100 kilm, so this engine currently is using using about a third less fuel. So when it comes to Towing diesel engines are just so much more efficient doesn’t mean in the life of the engine. It’S going to be cheaper, but certainly when towing a load, a diesel engine is going to um, make things a little bit less expensive, expensive.
The time has come we’re going to see how well this updated engine brake does with 14,000 lb behind it down our Hill, all right, so cruise control set at 110 and uh all right. First downshift 2500 rpm holding us pretty steady, actually 113 km an hour not too bad again. I am a little bit surprised, happily surprised with the Duramax it’s going to hold us at 113. That is really good. That is actually that’s better than the power stroke.
The Cummins was better but well. Cumins just has a dynamite engine brake sorry, exhaust breake, yeah, that’s uh! That is a massive Improvement wow. Last time I had the Duramax on this course. Um the exhaust brake was pretty pretty much not there.
I actually had to hit the brakes myself to slow the thing down the truck down yeah. They have done some tweaking to that exhaust brake and it is certainly working much much better uhoh. This thing’s got the hazards on can’t pull the load. This thing needs a Duramax in it. That’S what it’s missing put the Duramax engine in her she’ pull those logs up the hill, no problem.
What we got here – oh yeah, Western Star, let’s go probably got a Detroit Diesel 16 in there I’d guess: dd15. Maybe this exhaust breake is no joke holy right back down to 110, happily surprised how well this exhaust break is working. This Duramax really really like that, because Barone, that was one of the weaknesses of the first gen l5p in my opinion, was that weak exhaust break. We made her halfway with the old Duramax, I hate to say it, but I’m kind of liking, this truck I’m kind of liking it it’s pulling this load very well. The engine braking is awesome.
It’S the low-end power is there where I didn’t think it would be. This second gen l5p making me look bad with my predictions, but I like to see it on the backstretch of our Towing Loop. We got a lot more Hills and uh perfect to see how this diesel engine’s going to take them. Oh yeah, let’s get her working. Let’S get her working 2,000 RPM!
Oh no, sweat! Nothing! Oh boy! This Duramax not even sweating a little well in the distance. You can see the Beast: our number one hill, our exhaust breake, just working wonderfully.
Oh yeah, oh right back to 110. That is actually really really good, wow beautiful view back to the road all right here we go, let’s see, what’s going on here, all right 109 km an hour, downshift 110. What are we even doing here? This Duramax is walking all over my Towing loop, we’re like 2100 RPM. Oh my I I well.
First of all, that’s better than the power stroke. It puts the 67 Commons to Absolute. Shame, unfortunately, guys I love the cumin but uh. It is what it is. This thing’s barely turning over pulling this hill.
That is impressive. That literally may have been the best run up that hill of any engine I’ve tested granted. I have not tested the high output Power Stroke, but GM Duramax bringing the heat holy like look at our transmission. Temp, 59 C, it’s not even hot after we just pulled that big hill too holy. This thing just pulls up so well.
I was so completely wrong about my prediction about this thing not having enough flow and torque, and it would need to downshift what was I thinking. We got our final Hill here. Let’S see what this Duramax has [ Music ] got just wonderful, it doesn’t even lose speed. Okay, we dropped keter there down, shift right away, love to see it. The 67 [ __ ] logged all the way up here.
The power stroke was fine, but this Duramax is just crushing this Towing Loop. We are averaging 20.5 L per 100 km, which is roughly like 10.8 m per gallon. That is a fair bit worse fuel economy than first of all, the power stroke that got 12.
MP G G, as well as the cumin that finished with 11
9 and interestingly enough, when I was doing research for this truck, I found quite a few people commenting on poor fuel economy out of this engine. I will be doing a full-blown fuel economy test with this truck in a later video. So look forward to that, but yeah not the best fuel economy out of um the competition, oh yeah, just rips Jesus. This thing pulls well. We unloaded the trailer and, as you guys can probably tell this second gen l5p Duramax engine is growing on me.
A little bit um, I was vastly incorrect about my low-end torque Theory. There um this thing plenty of bottom end, torque good, on GM, really like what they’re doing with this engine – and I was incredibly happily surprised with the updated exhaust brake performance, the old Duramax or the first gen l5p. In my opinion, the exhaust brake was just. It was almost non-existent. This thing you notice it and it works very well and well in terms of performance as a whole.
This truck this engine. It is probably one of the best, if not the best engine I’ve had on my Towing loop, at least, which is pretty darn impressive. I was not expecting that out of this. This truck and engine combination. However, that being said next week or later down the line here we’ll be talking about some engine issues, because let me tell you this engine is not perfect, so don’t think otherwise.
Let me know what you guys think: do you agree with my assessment of this truck on my Towing course, or do you think I’m maybe a little bit fullish? Let me know what you think, as always guys if you like the video, don’t forget to leave that thumbs up and well, if you like, cool stuff like this, we got a couple more Duramax videos on the way, so don’t miss them enough of me, we see You in the next freaking video Jesus Christ,
