New gas engine?

[Scottly]

A lot of discussion about the Hurricane motor and the 2500/3500HD trucks. What about the possibility that the "new" 6.7L gas engine that Cummins has ending up in the HD trucks? Seems like the diesel is going to be bumped to 7.2L...Seems like that gas engine has been in development for a few years and I'm not sure where else Cummins would have a market for it. Thoughts?

 

[tjfdesmo]

A gas version of the Cummins, even with an aluminum head, will be way, way heavier than a Hemi, thus making their insufficient payload problem even worse. Maybe commercial chassis applications. I can also see Freightliner using it in a gasser motorhome chassis to take a bite out of Ferd's dominance in that market.

 

[rzr6-4]

A gas version of the Cummins, even with an aluminum head, will be way, way heavier than a Hemi, thus making their insufficient payload problem even worse. Maybe commercial chassis applications. I can also see Freightliner using it in a gasser motorhome chassis to take a bite out of Ferd's dominance in that market.

Different heads, I would assume NA so getting rid of turbos will save weight and complexity, smaller cooling system, fuel system would be simpler. It will certainly still be heavy but maybe not as bad as you think.

That hurricane has good power and tq on paper but you have to work it harder to get it. I can't imagine wanting to pull 24K across the state in a 2500 with a little turbo 3L, some larger NA motor would be the way to go. 6.7 Cummins block is a little overkill, but something.

Some people already say that the hemi is a race car motor and not a good choice for a truck, a turbo 3L would be way worse.

 

[tjfdesmo]

Different heads, I would assume NA so getting rid of turbos will save weight and complexity, smaller cooling system, fuel system would be simpler. It will certainly still be heavy but maybe not as bad as you think.

That hurricane has good power and tq on paper but you have to work it harder to get it. I can't imagine wanting to pull 24K across the state in a 2500 with a little turbo 3L, some larger NA motor would be the way to go. 6.7 Cummins block is a little overkill, but something.

Some people already say that the hemi is a race car motor and not a good choice for a truck, a turbo 3L would be way worse.

AFAIK it is turbocharged. I'd venture to say a 6.7 shortblock alone weighs more than a fully dressed 6.4 Hemi. I have gone across the scales in a 6.4 gasser at 23,160.

 

[rzr6-4]

AFAIK it is turbocharged. I'd venture to say a 6.7 shortblock alone weighs more than a fully dressed 6.4 Hemi.

That would be very strange. From the little reading I did, I'm seeing power ratings in the 320-350hp range. 6.7L turbo I would think you would make 400+ on accident. That's a lot of extra complexity and weight to carry around just to make less power than the 6.4. All that said though, it still has the same bore/stroke geometry as the diesel, which is why it is also supposed to have 660lbft of tq. So I guess it's similar in that way.

From what I am seeing:
Cummins block = 700lb
Cummins fully built = 1070lb (hopefully lighter in gas form but still likely in the 1k neighborhood.)
Full built 6.4 = 580lb
Full built 5.7 = 500lb

Your weight hypothesis seems be correct.

 

[tjfdesmo]

That would be very strange. From the little reading I did, I'm seeing power ratings in the 320-350hp range. 6.7L turbo I would think you would make 400+ on accident. That's a lot of extra complexity and weight to carry around just to make less power than the 6.4. All that said though, it still has the same bore/stroke geometry as the diesel, which is why it is also supposed to have 660lbft of tq. So I guess it's similar in that way.

From what I am seeing:
Cummins block = 700lb
Cummins fully built = 1070lb (hopefully lighter in gas form but still likely in the 1k neighborhood.)
Full built 6.4 = 580lb
Full built 5.7 = 500lb

Your weight hypothesis seems be correct.

It's similar torque because of the turbo. Low horsepower is due to long stroke, tall deck design, and high reciprocating weight limiting RPM potential. Secondly, less valve area with fewer cylinders will limit top-end horsepower potential.

 

[2003F350]

You would be surprised how light an all-aluminum I6 could actually end up being. Because let's face it, it likely WILL be an aluminum block with steel cylinder sleeve inserts. It wouldn't surprise me if they come in a LOT lower in weight than a CTD, and possibly in the ballpark or less than a Hemi.

 

[Ratman6161]

Different heads, I would assume NA so getting rid of turbos will save weight and complexity, smaller cooling system, fuel system would be simpler. It will certainly still be heavy but maybe not as bad as you think.

That hurricane has good power and tq on paper but you have to work it harder to get it. I can't imagine wanting to pull 24K across the state in a 2500 with a little turbo 3L, some larger NA motor would be the way to go. 6.7 Cummins block is a little overkill, but something.

Some people already say that the hemi is a race car motor and not a good choice for a truck, a turbo 3L would be way worse.

Some people might say it, but the 6.4L truck Hemi nis in no way a " race car motor". Ram ills it as an "HD" engine. Though it's the same basic design, it really is a very different engine than the 6.4L SRT found in cars and SUV's. I agree with you on a 3L gas turbo being bad in an HD truck though. Just look at Ford. They have been using their Eco Boost engine es in F150s and other places for years but fore the 250 a d 350 it's the 7.3 and 6.8. Finally, I think the poor payload numbers and high prices are something I'd li,e to see addressed before worrying about replacing the 6.4..

 

[Wild one]

Some people might say it, but the 6.4L truck Hemi nis in no way a " race car motor". Ram ills it as an "HD" engine. Though it's the same basic design, it really is a very different engine than the 6.4L SRT found in cars and SUV's. I agree with you on a 3L gas turbo being bad in an HD truck though. Just look at Ford. They have been using their Eco Boost engine es in F150s and other places for years but fore the 250 a d 350 it's the 7.3 and 6.8. Finally, I think the poor payload numbers and high prices are something I'd li,e to see addressed before worrying about replacing the 6.4..

Other then compression ratio / camshaft and intake manifold,there's not any real differances between a truck 6.4 and a pass car 6.4,both use the same crank and rods and after 2018 the same BGE block.The truck 6.4 actually uses the same basic heads as the Hellcats use.With a spring and valve change the truck heads become a hellcat head with a naturally aspirated intake manifold bolt pattern.

 

[Riccochet]

The specs on the Cummins ISB6.7 gas engine are not good. Well, the torque is good at 660 ft/lbs, but only 325 HP in the high output trim with the standard output at 250 HP. And it weighs as much as the diesel version. Meaning it'd be a SLOW PIG.

I don't want that. Nope.

Give us a 7.0L 426 pushrod V8. Make it do 475 HP and 500 ft/lbs.

 

[rzr6-4]

Give us a 7.0L 426 pushrod V8. Make it do 475 HP and 500 ft/lbs.

So just a massive new LS motor.

 

[tjfdesmo]

You would be surprised how light an all-aluminum I6 could actually end up being. Because let's face it, it likely WILL be an aluminum block with steel cylinder sleeve inserts. It wouldn't surprise me if they come in a LOT lower in weight than a CTD, and possibly in the ballpark or less than a Hemi.

Except Cummins has said the Octane gasoline engine is "identical from the head gasket down", so that means the bottom end is just as heavy as the diesel.

 

[06 Dodge]

The specs on the Cummins ISB6.7 gas engine are not good. Well, the torque is good at 660 ft/lbs, but only 325 HP in the high output trim with the standard output at 250 HP. And it weighs as much as the diesel version. Meaning it'd be a SLOW PIG.

I don't want that. Nope.

Give us a 7.0L 426 pushrod V8. Make it do 475 HP and 500 ft/lbs.

I'll take TQ over HP 24/7/365

 

[Wild one]

So just a massive new LS motor.

With better heads,the best LS heads are still a far cry from the Apache or truck 6.4 heads,lol
One of the reasons why a late model Mopar engine produces more power per pound of nitrous compared to the LS's is because the heads flow more,and the intake port is big enough to handle the atmosphere oxygen displacement you get when injecting nitrous

 

[Riccochet]

I'll take TQ over HP 24/7/365

Torque is fun until you need to accelerate. It's really fun taking 3 minutes to hit 60 MPH, said no one ever.

Torque in a street car, sure, give me all the torques from stop light to stop light. Torque in a HD truck, fine, it's needed, but getting up to highway speed is painful without horsepower.

 

[Riccochet]

With better heads,the best LS heads are still a far cry from the Apache or truck 6.4 heads,lol
One of the reasons why a late model Mopar engine produces more power per pound of nitrous compared to the LS's is because the heads flow more,and the intake port is big enough to handle the atmosphere oxygen displacement you get when injecting nitrous

Also the reason why every nitro engine in NHRA is a Hemi.

 

[nlambert182]

Considering I saw the 7.2L Cummins prototype engine in person back ~2009/2010 and it still hasn't came out yet... I don't know that it ever will. I wish it would. They'd be better off cramming the X10 into the 2500/3500 chassis. It's already fuel agnostic, so there will be diesel and gas variants of the same base engine that were designed that way instead of trying to retrofit a 6.7 to do the same thing.

Not sure what I feel about the gas engine yet. I am not a fan of gas engines for heavy towing anyhow (personal preference) but I don't see how it could be a benefit if it weighs as much as the 6.7 diesel version. Less HP/Less TQ (than the diesel), no weight savings, and likely even worse mpg than the 6.4.

 

[Riccochet]

Considering I saw the 7.2L Cummins prototype engine in person back ~2009/2010 and it still hasn't came out yet... I don't know that it ever will. I wish it would. They'd be better off cramming the X10 into the 2500/3500 chassis. It's already fuel agnostic, so there will be diesel and gas variants of the same base engine that were designed that way instead of trying to retrofit a 6.7 to do the same thing.

Not sure what I feel about the gas engine yet. I am not a fan of gas engines for heavy towing anyhow (personal preference) but I don't see how it could be a benefit if it weighs as much as the 6.7 diesel version. Less HP/Less TQ (than the diesel), no weight savings, and likely even worse mpg than the 6.4.

Cummins had the 7.2 developed. Problem is our .gov decides to freebase a big pile of stupid and change the regulations which puts Cummins back to the drawing board every couple years.

And honestly the HP and torque wars has hit the point of ridiculousness. We get it, all the HP and all the torque. But it really doesn't equate to a better towing experience. You hit the wall of diminished returns where all the extra power and torque are meaningless in real world applications. What we had 5+ years ago will effortlessly tow up the steepest grades in the country. Do you need 1500 ft/lbs to tow a 20,000 lb 5th wheel? No. You're not going to see a difference between 1000 ft/lbs and 1500 ft/lbs at 55-65 MPH up grade. Both won't even be breaking a sweat.

I feel like they should be focusing on efficiency a bit more at this point. Same trailer towed with a 2015 or 2024 3500 or F350 will get roughly the same fuel efficiency. Make some gains here, the power is good.

 

[Wild one]

Also the reason why every nitro engine in NHRA is a Hemi.

It's Hemi based that's about all,lol
The early Hemi's are alot differant then the 3rd Gen Hemi's,which aren't really a Hemispherical combustion chamber like the real early Gen 1 and Gen 2 hemi's were

 

[tjfdesmo]

Lest anyone thinks Cummins is a victim, they are as woke a company as you will ever find anywhere. Rainbow flags, DEI aplenty, supported BLM, and signed onto letters condemning Trump for trying to undo strangling environmental regulations. The prior CEO, Linebarger, was insane with this crap.