When will it end

ShinerBock wrote:

FishOnOne wrote:


Cummins has the biggest displacement?

Link

Yes, the Cummins 6.7L has the biggest displacement of the three. Doing the math with the bore, stroke, and number of cylinders; the 6.7L Powerstroke comes out to be 406.16 (406) cid and the 6.7L Cummins 407.59 (408) cid.

Even Ford lists it as a 406..... LINK

And Truck Trend...... LINK

And Ford again(page 75)...... LINK


So I am not where that diesel hub website is getting their numbers. Especially when simply doing the math will prove that it is false.

You're correct.... I doubt anyone will go with 409cu anyways as this number is legendary.

FishOnOne wrote:


Cummins has the biggest displacement?

Link

Yes, the Cummins 6.7L has the biggest displacement of the three. Doing the math with the bore, stroke, and number of cylinders; the 6.7L Powerstroke comes out to be 406.16 (406) cid and the 6.7L Cummins 407.59 (408) cid.

Even Ford lists it as a 406..... LINK

And Truck Trend...... LINK

And Ford again(page 75)...... LINK


So I am not where that diesel hub website is getting their numbers. Especially when simply doing the math will prove that it is false.

FishOnOne wrote:
Cummins has the biggest displacement?

Link

Does Ford or GM have a BIGGER displacement? If not, then yes, Cummins (tied with Ford) has the biggest displacement.;)

Come on Fishie, as much as you like to troll and argue semantics, you're really picking this fight?

ShinerBock wrote:

FishOnOne wrote:


I agree and understand your point. I guess I was pointing out in previous tests there has been no real coorilation to compression ratio with these particular trucks since there are so many variables at play. And I do find this stuff interesting as well.

I didn't say there was a direct correlation. I just said it was interesting. I also pointed out some of the other factors that have effect on fuel efficiency in that very same post like turbo charger efficiency at certain rpms and fuel pressures. The Cummins higher compression ratio and how the turbocharger was designed for lower rpm efficiency plays a big part as to why it generally achieves the best fuel economy of the three even though it has the biggest displacement.

Cummins has the biggest displacement?

Link

FishOnOne wrote:


I agree and understand your point. I guess I was pointing out in previous tests there has been no real coorilation to compression ratio with these particular trucks since there are so many variables at play. And I do find this stuff interesting as well.

I didn't say there was a direct correlation. I just said it was interesting. I also pointed out some of the other factors that have effect on fuel efficiency in that very same post like turbo charger efficiency at certain rpms and fuel pressures. The Cummins higher compression ratio and how the turbocharger was designed for lower rpm efficiency plays a big part as to why it generally achieves the best fuel economy of the three even though it has the biggest displacement.

ShinerBock wrote:

FishOnOne wrote:

I agree in general with the compression ratio but add a turbo and you add another variable with compression. The Duramax has actually at one time (LBZ) reduced compression, but improved performance and fuel economy over the previous gen which started out at 17.5

Even with a turbo, compression ratio still plays a factor in getting more energy out a drop a fuel. However, as with the other examples I have given, this is not the only reason for better fuel economy. GM was able to improve fuel economy and power through more aggressive tuning which backs up my previous statements.

Also, if you read what I stated earlier again I said "Interestingly, this compression ratio spread matched up perfectly with PUTC's last diesel truck comparison." meaning that I found it interesting that compression ratio spread matched up perfectly to the PUTC test. You can disagree with me or not, but I will still find it interesting.

The real world fuel economy on Fuelly.com shows a different story though. There the average fuel economy for 2014-2017 3/4 tons shows GM at 14.6 mpg and the Ford at 14.2 mpg. However, Cummins is still ahead of the both of them with an average of 15.7 mpg. Regardless I still find the compression ratio and PUTC test fuel economy spreads being very close..... interesting.

I agree and understand your point. I guess I was pointing out in previous tests there has been no real coorilation to compression ratio with these particular trucks since there are so many variables at play. And I do find this stuff interesting as well.

FishOnOne wrote:

I agree in general with the compression ratio but add a turbo and you add another variable with compression. The Duramax has actually at one time (LBZ) reduced compression, but improved performance and fuel economy over the previous gen which started out at 17.5

Even with a turbo, compression ratio still plays a factor in getting more energy out a drop a fuel. However, as with the other examples I have given, this is not the only reason for better fuel economy. GM was able to improve fuel economy and power through more aggressive tuning which backs up my previous statements.

Also, if you read what I stated earlier again I said "Interestingly, this compression ratio spread matched up perfectly with PUTC's last diesel truck comparison." meaning that I found it interesting that compression ratio spread matched up perfectly to the PUTC test. You can disagree with me or not, but I will still find it interesting.

The real world fuel economy on Fuelly.com shows a different story though. There the average fuel economy for 2014-2017 3/4 tons shows GM at 14.6 mpg and the Ford at 14.2 mpg. However, Cummins is still ahead of the both of them with an average of 15.7 mpg. Regardless I still find the compression ratio and PUTC test fuel economy spreads being very close..... interesting.

ShinerBock wrote:

OldSmokey wrote:


nature of the beast.. gas engines make hp at high rpm. only way to reduce rpm and keep power is with a turbo or two like the ecoboost.. which is anything but eco.

Not necessarily. An engines stroke length and cam profile has a lot to do with when it reaches peak torque as well. The old Ford I6 300(4.9L) made peak torque at 1,600 rpms and later models did at 2,000 spm due to it's almost 4 inch stroke. Truck variants of the Chevy 350(5.7L) made peak torque at 2,400 rpm due to their cam profile.

Naturally aspirated under square bored engines has a lot to do with it as well.

ShinerBock wrote:

FishOnOne wrote:


I disagree with the compression ratio analogy as we've seen varying performance from all three.

What we don't know are the conditions in which each manufacturer violates emission standards.

Believe what you want to believe, but that doesn't mean that you can't change the fact that a higher compression ratio will improve fuel economy. Maybe you should brush up on your engine knowledge. What's the connection between compression ratio and fuel economy?

And yes, we don't know the conditions in which each manufacturer violated emissions standards since none has been proven and the lawsuit is from a law firm with a history of frivolous emissions cases. So to this point you can't say one has over the other. Although, even the lawsuit claims that it happens over time and the trucks that were tested in the PUTC test were new.

Oh, and if the the Cummins or GM diesels do not meet emissions, don't you think the EPA would have put a stop sale on them like they did with the Ecodiesel and VW diesels by now?

I agree in general with the compression ratio but add a turbo and you add another variable with compression. The Duramax has actually at one time (LBZ) reduced compression, but improved performance and fuel economy over the previous gen which started out at 17.5

FishOnOne wrote:


I disagree with the compression ratio analogy as we've seen varying performance from all three.

What we don't know are the conditions in which each manufacturer violates emission standards.

Believe what you want to believe, but that doesn't mean that you can change the fact that a higher compression ratio will improve fuel economy. Maybe you should brush up on your engine knowledge. What's the connection between compression ratio and fuel economy?

And yes, we don't know the conditions in which each manufacturer violated emissions standards since none has been proven and the lawsuit is from a law firm with a history of frivolous emissions cases. So to this point you can't say one has over the other. Although, even the lawsuit claims that it happens over time and the trucks that were tested in the PUTC test were new.

Oh, and if the the Cummins or GM diesels do not meet emissions, don't you think the EPA would have put a stop sale on them like they did with the Ecodiesel and VW diesels by now?