Horse-torque Duramax vs. Cummins

[Muff]

Seems like us duramax guys are still behind the cummins guys when it comes to big horsepower competition trucks, im speaking from sled pulling experience not dyno numbers or drag racing. What are we lacking? Just not enough R&D? More years of testing different nozzles, nozzle spray angles, pistons, heads, etc. etc....would a switch to a mechanical fuel system aid in bringing us closer together?

Just creating this topic to get a different style discussion going on with guys who have expierence in big horsepower applications to see what everybody else is thinking.

Is it more cost effective to just build a cummins? Are they a better performing powerplant at 1500hp+?

Interested to hear what you guys have to say :thumb:

 

[TheBac]

I6 vs V8, we will never make the tq numbers that they can. IMO simple as that.

 

[gmduramax]

I6 vs V8, we will never make the tq numbers that they can. IMO simple as that.

They just make their torque at a lower rpm I believe, IIRC when dmitri would dyno woudnt his torque numbers be close with cummins trucks?


I think cummins motor is stronger than the Duramax. Stock and built.

 

[PureHybrid]

They just make their torque at a lower rpm I believe, IIRC when dmitri would dyno woudnt his torque numbers be close with cummins trucks?


I think cummins motor is stronger than the Duramax. Stock and built.

Stock casting isn't any stronger than a duramax. Most Cummins guys that pull are running a deckplate anyhow.

For the Cummins common rail, it's pretty on par with the Duramax (pending your wallet size). Once you go mechanical injection it's a whole other world. I just think guys are more willing to dump loads of cash into the i6 platform vs others. The cranks actually hold up LOL

 

[Chevy1925]

Stock casting isn't any stronger than a duramax. Most Cummins guys that pull are running a deckplate anyhow.

For the Cummins common rail, it's pretty on par with the Duramax (pending your wallet size). Once you go mechanical injection it's a whole other world. I just think guys are more willing to dump loads of cash into the i6 platform vs others. The cranks actually hold up LOL

Actually, their stock cranks are no better above 1k hp. They still snap lol

 

[hondarider552]

I haven't seen any Cummins forums that have a running pole of failed crankshafts...

 

[hondarider552]

But then again, I haven't found a Cummins forum in 10 years that's worth a crap, besides compD and I haven't been on there since 2014 haha.

 

[ikeG]

I6 vs V8, we will never make the tq numbers that they can. IMO simple as that.

Top performing trucks never run rpms close to their peak torque numbers. In fact, especially in a d.o.t. tire class, torque is your enemy.

Let me rephrase that, you try to stay away from your peak torque rpm. For instance, in any of the single charger classes, you want to to run down the track 4500-5500 rpms, depending on the power level. Peak torque is at roughly 3000 rpms on most setups.

 

[Ne-max]

Many pulling classes rules favor the cummins engines.

 

[zakkb787]

My thoughts are on par with Tom. Never get a v8 to have the torque an in-line 6 can produce with the same mods.

 

[PureHybrid]

Same cubic inches will produce similar torque output. The bore / stroke / cylinder configuration will dictate at what RPM.

 

[PureHybrid]

Actually, their stock cranks are no better above 1k hp. They still snap lol

No better? Keep dreaming. Nobody even considers an aftermarket crank for a Cummins till 1500+

Might snap the drive flange from all that low end tq bruh :roflmao:

 

[Hambone]

Correct me if I’m wrong but isn’t a I6 pretty well balanced where a V8 takes more counter weight to balance which just adds more rotating mass?
Should also be noted that there is way more than just HP/TQ that wins Pulling/Racing
And usually it boils down to who can cheat the best and not get caught lol:roflmao:

 

[IOWA LLY]

My thoughts are on par with Tom. Never get a v8 to have the torque an in-line 6 can produce with the same mods.

I6 vs V8, we will never make the tq numbers that they can. IMO simple as that.

That’s has nothing whatsoever to do with it. I get so sick of hearing this argument. The internal parts don’t know if they are in an inline 6 or a V8 or whatever. There is nothing magical about an inline 6.

Rod length has everything to do with torque output in a Diesel. That is the primary reason why you typically see a Cummins engine make more torque then a Duramax.

Having said all that, the Cummins engine is physically much bigger then the Duramax. Which means more room for things like deck plates, crank stroke, rod length, etc. The Duramax will always be somewhat limited compared to a Cummins simply because we don’t have the room in he bottom end to do some of the things the Cummins guys can do.

Strength is also a factor but the Cummins engines have their own issues there as well. Don’t let the Cummins guys fool you, their engine was actually scrapped because it was considered junk by the original design team and dodge revived it in an attempt to save their trucks and their market share. Which worked obviously.


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[Chevy1925]

No better? Keep dreaming. Nobody even considers an aftermarket crank for a Cummins till 1500+



Might snap the drive flange from all that low end tq bruh :roflmao:

I haven't seen any Cummins forums that have a running pole of failed crankshafts...

Don’t have to believe me. Beyond 1000, reliability of the stock crank drops quite a bit. They don’t die the same way ours does but they have their reasons

I’ve been pretty in depth in cummins stuff for a bit

 

[zakkb787]

James I’m really not trying to pick a fight here because I know I will lose but that’s kinda exactly what I was saying... sure with the same size bore and stroke an in-line 6 vs a v8 is a no brainer. The 6 would be quite a bit smaller and not produce near the power and torque the v8 would. But. But a 6.6 duramax beside a 6.7 Cummins (not exactly the same but similar size motors liter wise) the Cummins is a torque beast. The duramax will be a better revving probably higher hp engine but the Cummins just tows amazingly. It’s not just because the in-line 6 is magical, but physically a lot of the parts are bigger because the liter numbers are similar. Therefore. Cummins has more torque BECAUSE it’s 2 less cylinders and still the same size. Just my .02. Again I don’t want to start another fight on a thread cause no one wants that. So please don’t take anything the wrong way lol

 

[Chevy1925]

Oh I’m not in the torque battle going on. I’m just saying where the weak point for the stock crank is hp wise.

 

[Ne-max]

I see just as many cummins blocks fail as duramax cranks break

 

[Muff]

Oh I’m not in the torque battle going on. I’m just saying where the weak point for the stock crank is hp wise.

can you elaborate on this at all James?

I see just as many cummins blocks fail as duramax cranks break

can you elaborate on this at all as well?

 

[Firefightkev]

Correct me if I’m wrong but isn’t a I6 pretty well balanced where a V8 takes more counter weight to balance which just adds more rotating mass?
Should also be noted that there is way more than just HP/TQ that wins Pulling/Racing
And usually it boils down to who can cheat the best and not get caught lol:roflmao:

Tom Brady? :roflmao: