Horse-torque Duramax vs. Cummins

clrussell

pro-procrastinator
Sep 23, 2013
5,928
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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:

100% agree on the last line
 

joshd472

New member
Oct 10, 2016
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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

You actually done a good job of explaining your theory and I agree with it.
 

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,517
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Central OH
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

But does the 6.7 REALLY have more tq? In factory trim maybe a little (pending what year), but that all comes down to the factory calibration. It might FEEL like it does, but it's just the delivery method. An engine with 900lbft at 1500rpm will be more fun to drive than an engine with 900lbft at 2000rpm.

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.

Call around to diesel shops and ask for a 1200hp Cummins long block, guess how many sell you an aftermarket crank? Slim to none, it's not a common failure point. Obviously some parts can and will fail at any power level.

can you elaborate on this at all as well?

They like to split the cylinder walls into the water jacket.
 

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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But does the 6.7 REALLY have more tq? In factory trim maybe a little (pending what year), but that all comes down to the factory calibration. It might FEEL like it does, but it's just the delivery method. An engine with 900lbft at 1500rpm will be more fun to drive than an engine with 900lbft at 2000rpm.







Call around to diesel shops and ask for a 1200hp Cummins long block, guess how many sell you an aftermarket crank? Slim to none, it's not a common failure point. Obviously some parts can and will fail at any power level.







They like to split the cylinder walls into the water jacket.



:thumb:
 

zakkb787

<that’s not me...
Sep 29, 2014
2,340
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Granite Falls NC
Jesse I guess what I’m saying is while the numbers will be the same, like you said they hit lower than the v8 guys do. So. In a way they have more torque as they produce more at lower rpm but then again it’s the same because it’s the same peak numbers. So I guess a more accurate way to say it they’re more torquey? Maybe that makes sense. I don’t know it’s to early for this :roflmao:don’t know nothin bout cranks and blocks.
 

Muff

Just Learning
Oct 7, 2013
1,063
0
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Butler, Pa
Jesse I guess what I’m saying is while the numbers will be the same, like you said they hit lower than the v8 guys do. So. In a way they have more torque as they produce more at lower rpm but then again it’s the same because it’s the same peak numbers. So I guess a more accurate way to say it they’re more torquey? Maybe that makes sense. I don’t know it’s to early for this :roflmao:don’t know nothin bout cranks and blocks.

You do not know anything about the topic of this thread please refrain from contaminaing it with mumbo jumbo. (Do not take any offense please). Trying to make an informational thread with lots of good content which we are lacking on this forum lately.

Thread subject. What do we need to do to become more competive at Big hp 13-1500+. If your desiring 1500+ in a competion platform is it smarter to build a cummins.
 

Hambone

Always learning
Jan 24, 2016
572
0
16
Florida
Aren’t aluminum rods making there way into the big Hp builds now?
Top fuel motors have been using them along time with good success but you only get a few passes before they are toast
 

ikeG

Oughta Know Better
Apr 19, 2011
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Aren’t aluminum rods making there way into the big Hp builds now?
Top fuel motors have been using them along time with good success but you only get a few passes before they are toast
Wagler has been using them for a while. Kusilek's Cummins Killer most notably

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ikeG

Oughta Know Better
Apr 19, 2011
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You do not know anything about the topic of this thread please refrain from contaminaing it with mumbo jumbo. (Do not take any offense please). Trying to make an informational thread with lots of good content which we are lacking on this forum lately.

Thread subject. What do we need to do to become more competive at Big hp 13-1500+. If your desiring 1500+ in a competion platform is it smarter to build a cummins.
The thing with pulling is if you are not a 100% diy guy, you can have turn key, class leading power just by writing a check to companies like haisley & scheid. I'm talking best of the best, pump set already, dyno-tuned, just bolt in(which they'll do that for you too). All in-house. Just like ordering a rousch Yates engine for late model racing. And guess what they specialize in: Cummins. For decades, they've been winning in pulling.

With a dmax, it's a lot more difficult. Lack of similar shops, the wiring headache, more difficult exhaust plumbing, etc. Although shops like werhli, Danville, hsp will do it all for you, it just hasn't taken off like the 6 cyl crowd. Seems like Werhli has been doing bit more of this, including chassis as of last few years.

I don't think it's that a dmax can't produce a dyno graph good enough, it's just that it's more difficult. If I had to add up all the hours I have in our truck over the years, it seems like it would be impossible to give someone a bill for that.

This is my two cents coming from pulling experience, no drag racing experience other than some goofing around in grocery getters.

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diesel-max

Haisley Never heard of her
Oct 20, 2011
172
16
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IN
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:



I'd have to agree, we are lacking. I for sure accredit the Cummins worlds success to MANY years of development on the Duramax, no matter how far we advance they still have 12 years on us.

Although there is great companies specializing and working greatly with Duramax stuff, I feel that there is no one doing quite what Haisley, Scheid ect. do.

With dynoing in extreme controlled ways, one small thing at a time trying EVERYTHING. With Mark having his dyno in recent years is awesome as now we have a great guru going at testing in a controlled educated way.
Also with every joe blow and his brother it seems build 'mechanical' injectors any more, so there is tons of fuel side testing.

With Exergy and S&S in the market honestly in 'short years' compared to mechanical builders we now have testing coming that mechanical guys did YEARS ago.

I know S&S is going to be doing some testing this winter on some nozzle's and such. Which I haven't seen a whole lot of done by others yet. Also with Them having a dyno in place and having some people to be able to work with right in house I think is going to help us out a ton!

Also, I've yet to see extensive piston bowl testing... I'd hate to see how many different designs and money have went into testing that in the Cummins world... and piston testing with different injectors/angles..

These are just a few examples, sure a few people may have tested this or that but nothing like the Cummins world. They test as much wild stuff as the SuperFarm guys LOL

In the world of pulling its hard to be bias on any products until you just flat test EVERYTHING. Some things will all ways suck but you never know until you try. I've been to ALOT of engine dynos, at many different places and have seen some of the smallest wildest things you'd never think of make power... but those small tricks come from YEARS of testing.

But what do I know.:thumb:
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,759
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The thing with pulling is if you are not a 100% diy guy, you can have turn key, class leading power just by writing a check to companies like haisley & scheid. I'm talking best of the best, pump set already, dyno-tuned, just bolt in(which they'll do that for you too). All in-house. Just like ordering a rousch Yates engine for late model racing. And guess what they specialize in: Cummins. For decades, they've been winning in pulling.

With a dmax, it's a lot more difficult. Lack of similar shops, the wiring headache, more difficult exhaust plumbing, etc. Although shops like werhli, Danville, hsp will do it all for you, it just hasn't taken off like the 6 cyl crowd. Seems like Werhli has been doing bit more of this, including chassis as of last few years.

I don't think it's that a dmax can't produce a dyno graph good enough, it's just that it's more difficult. If I had to add up all the hours I have in our truck over the years, it seems like it would be impossible to give someone a bill for that.

This is my two cents coming from pulling experience, no drag racing experience other than some goofing around in grocery getters.

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^^this. the cummins boys have the following to keep the drive and research way up and many more guys with pocket books that open up large bills to keep pushing it. Wagler is really the only ones pushing a dmax and R&Ding the engine to get on par with a cummins and even still, the following of dmax guys to be at that same level is very low.

you could say the "Cummins economy" is much larger than the "Duramax economy" at this time but we are progressing at a decent rate.
 

ikeG

Oughta Know Better
Apr 19, 2011
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The trickle down effect from 50+ years of diesel tractor sled pulling only helps the mechanical Cummins, not us. Look at lavon Miller's ucc dyno setup. Triple chargers and a sigma pump. Super stock diesel tractors made that much power with those parts 20(guesstimate) years ago.....

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diesel-max

Haisley Never heard of her
Oct 20, 2011
172
16
18
IN
^^this. the cummins boys have the following to keep the drive and research way up and many more guys with pocket books that open up large bills to keep pushing it. Wagler is really the only ones pushing a dmax and R&Ding the engine to get on par with a cummins and even still, the following of dmax guys to be at that same level is very low.

you could say the "Cummins economy" is much larger than the "Duramax economy" at this time but we are progressing at a decent rate.

I give great credit for what Jeremy has done and done for me, I understand from a business side of things why he has to but, he seems to have 1 million projects going and nothing seems to be 100% dialed perfect. Nothing against him, but I would like to see things taken and perfected one at a time.

Haisley is 100% dedicated to Cummins truck pulling, mind you - you can buy parts for some street/strip stuff here and there. but walk in their door and it is Cummins truck pulling 101. There is a reason they are the best. Hands down. There is no one 100% Duramax only PULLING only.
 

Ne-max

I like turtles
Nov 15, 2011
3,361
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I give great credit for what Jeremy has done and done for me, I understand from a business side of things why he has to but, he seems to have 1 million projects going and nothing seems to be 100% dialed perfect. Nothing against him, but I would like to see things taken and perfected one at a time.

Haisley is 100% dedicated to Cummins truck pulling, mind you - you can buy parts for some street/strip stuff here and there. but walk in their door and it is Cummins truck pulling 101. There is a reason they are the best. Hands down. There is no one 100% Duramax only PULLING only.

I agree with this 100% DX this. DX that. Get the thing dialed in and figured out before you promote it. I have yet seen one solid pull, run or dyno from it. All it does is revvs up in parking lots. He has some bad ads products but no details to them.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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I give great credit for what Jeremy has done and done for me, I understand from a business side of things why he has to but, he seems to have 1 million projects going and nothing seems to be 100% dialed perfect. Nothing against him, but I would like to see things taken and perfected one at a time.

Haisley is 100% dedicated to Cummins truck pulling, mind you - you can buy parts for some street/strip stuff here and there. but walk in their door and it is Cummins truck pulling 101. There is a reason they are the best. Hands down. There is no one 100% Duramax only PULLING only.

I agree with this 100% DX this. DX that. Get the thing dialed in and figured out before you promote it. I have yet seen one solid pull, run or dyno from it. All it does is revvs up in parking lots. He has some bad ads products but no details to them.

jeremy has to market this way to get money in the door though, so i see both sides. he has not had the years and years of r&d that cummins has seen along with following. he has to get capital to progress, that means money from you and i and there are only so many of us to go around so getting guys to switch or bringing new money in has to be done. 20-25 years ago, Haisley was in the same shoes as Wagler. You do all you can to market what you have to generate cash flow. jeremys stuff may not be 100% the best but it works and it only gets better from what ive seen. hell i think alot of his stuff at 90% is better than stuff i seen from places thats 110% lol.

We have a bad ass platform to build from, its a matter of getting the amount of racers needed and cash to go with. Fleece is larger in cummins now that dmax in pulling, that tells ya something there too.
 

diesel-max

Haisley Never heard of her
Oct 20, 2011
172
16
18
IN
I give great credit for what Jeremy has done and done for me, I understand from a business side of things why he has to but, he seems to have 1 million projects going and nothing seems to be 100% dialed perfect. Nothing against him, but I would like to see things taken and perfected one at a time.

I'm going to just Quote myself in this post as I reread my first line in response to the last post.
 

IOWA LLY

Yes, its really me
Feb 23, 2007
2,275
4
0
The trickle down effect from 50+ years of diesel tractor sled pulling only helps the mechanical Cummins, not us. Look at lavon Miller's ucc dyno setup. Triple chargers and a sigma pump. Super stock diesel tractors made that much power with those parts 20(guesstimate) years ago.....

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This is very true but a lot of the technology crosses over. Turbo technology for example is one of the biggest game changers in Diesel performance in the last 5-10 year’s.

I think the the biggest challenge in getting big Duramax power for sled pulling at this point is lack of bottom end room. Longer stroke may or may not help, but a deck plate and longer rods certainly would. In my opinion. At the very least it would allow them to make more torque. I don’t agree with not using peak torque for sled pulling. I’ve seen enough winning setups that rely more on torque then peak horsepower to go along with the “spin it to win it” theory. Just my experience and 2 cents. Not trying to pick a fight.


I also think that we have a ways to go on the fuel side of things to match the P and Sigma pumps. And that might also require better controllers. Not just injector and CP3 technology.


I think with company’s like Wagler, Exergy and S&S working on some very important aspects we will see some big gains in the next year or 2. I also think that the booming Trump economy will play as big a part in that as anything. Diesel stuff seems to picking back up in my area substantially.


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ikeG

Oughta Know Better
Apr 19, 2011
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Watch this video. More importantly, listen to the trucks. https://youtu.be/fqv_u1O9A1E

Which of the trucks is using it's peak torque? My point was this: when limited to d.o.t. tires, and at this power level, you try to stay well above your peak torque level.

Torque is a by-product of putting in the work to make the most power you can. But torque can work against you on dirt. For example, our engine made it's peak torque @ just shy of 3k rpm. And the curve goes down from there. Peak hp @ 3450 rpm. Thing is, we never want to run rpms this low down the track. If you geared your truck to run an rpm range right in the thick of the torque curve, 1- it would never keep a class-competitive sized charger lit & 2-it would eat up drivetrain and engine parts worse than we already do.

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