6.4 2500- A different perspective

[6.4 dude]

My 12' 5.7 had mds.....

 

[SouthTexan]

Mds debuted in the 5.7l hemi in 1500 trucks in

You are correct. It was the 8-speed that gave it the jump in fuel economy.

 

[MANual_puller]

My 12' 5.7 had mds.....

In a 2500 or 1500?

 

[reek]

this is anecdotal but, I just got back from a 4 day round trip to Monterey from Sacramento. 2015 ram 2500 6.4 4x4 CC 4.10 rear end, always drive with MDS turned off. Lots of hills around Monterey, traveling at 70 -80 mph mostly highway. 17 miles/gallon. Usually, driving around town and stop/go to work 11-12 mpg

My 08 tundra 5.7 with 4.30 rear end quad cab 4x4 always got around 16 -18 highway.

My 14 ram 1500 5.7 QC 4x4 6 speed, mds off, with 3.55 rear end got around 16-18 highway also.

 

[SouthTexan]

this is anecdotal but, I just got back from a 4 day round trip to Monterey from Sacramento. 2015 ram 2500 6.4 4x4 CC 4.10 rear end, always drive with MDS turned off. Lots of hills around Monterey, traveling at 70 -80 mph mostly highway. 17 miles/gallon. Usually, driving around town and stop/go to work 11-12 mpg

My 08 tundra 5.7 with 4.30 rear end quad cab 4x4 always got around 16 -18 highway.

My 14 ram 1500 5.7 QC 4x4 6 speed, mds off, with 3.55 rear end got around 16-18 highway also.

EVIC or hand calculation?

 

[reek]

EVIC or hand calculation?

trip meter/odo divided by gallons per gas stop. I really don't trust the EVIC on gas mileage nor that oil change meter either. I don't know if tire pressure made a difference but I had 60 psi front 80 psi rears - forgot to deflate before I took off after doing some hauling prior. AC was off, does that even matter these days for fuel economy?

 

[River19]

I'm sorry guys but this is really splitting hairs here.......in the real world, or at least the one I drive in.....there is no real meaningful difference between 14.9mpg and 16mpg for me. On a hunting trip driving from New England to MT or SD it is the difference of $20 each way on a $300 gas bill......to me that is virtually no difference whatsoever.

At that point, it will come down to payload, features and price a heck of a lot more than fuel economy.

The Eco Diesel is the first rig that really had enough of an improvement in fuel economy to make me take notice. Every gasser seems to be a 14-17mpg rig with occasional better performances and worse performances. It is what it is. The biggest difference in the past 15 years has been that while the fuel economy is very similar, the power levels have almost doubled for that economy.

 

[drittal]

^^^ Ed Zachary ^^^

All the little improvement add up over time, but currently the big gas options in 150/1500 are within 1mpg in real world usage. Same for the 6.0/6.2/6.4 with the Ram having the lead.

 

[SouthTexan]

I'm sorry guys but this is really splitting hairs here.......in the real world, or at least the one I drive in.....there is no real meaningful difference between 14.9mpg and 16mpg for me. On a hunting trip driving from New England to MT or SD it is the difference of $20 each way on a $300 gas bill......to me that is virtually no difference whatsoever.

At that point, it will come down to payload, features and price a heck of a lot more than fuel economy.

The Eco Diesel is the first rig that really had enough of an improvement in fuel economy to make me take notice. Every gasser seems to be a 14-17mpg rig with occasional better performances and worse performances. It is what it is. The biggest difference in the past 15 years has been that while the fuel economy is very similar, the power levels have almost doubled for that economy.

This is more a case where Drittal wants to challenge what is said just because it was me who said it and anything I say is automatically seen as negative or malicious even when it is not.

My point was that when the Ecoboost came out, it did deliver better mileage than other V8 engines while also having better performance and capabilities than most V8s at the time. It was outperforming the big GM 6.2L (non Ecotec) while returning better fuel economy than the substantially less powerful GM 5.3L (non Ecotec) which had the best V8 fuel economy at the time. Yes the difference is small as are most fuel economy improvements that are made to the more powerful half ton engine option, but that was not my point.

The thing with the Ecodiesel is that you loose performance, payload, and tow rating to gain fuel mileage to where engines like the Ecoboost you gained performance, payload, and towing rating while still gaining some fuel mileage. Then again, does't less powerful and capable engine options usually get less fuel economy than their more powerful and capable options(except for HD trucks)?

Taking a look at it though, I would have to wonder why someone that doesn't tow that much weight or very often would even get the Ecodiesel over the 3.6L. The 3.6L has better performance, better payload, and their tow ratings are not that much different gear ratio for gear ratio with even being the same in some configurations. Add the fact that Fuelly has the 3.6L at averaging 20 mpg and the Ecodiesel averaging 22.5 mpg, the fuel cost would be more for the Ecodiesel given prices being at $1.50 for regular and diesel being $.20 more. I can see paying more for better performance and more capabilities even if the fuel mileage was less, but not for less performance and less capabilities.

 

[SouthTexan]

trip meter/odo divided by gallons per gas stop. I really don't trust the EVIC on gas mileage nor that oil change meter either. I don't know if tire pressure made a difference but I had 60 psi front 80 psi rears - forgot to deflate before I took off after doing some hauling prior. AC was off, does that even matter these days for fuel economy?

The parasitic drain from the A/C does not matter that much with bigger engines as it does with small ones.

 

[drittal]

However if you compared it to other vehicles that it was as capable and with the same or better performance like the Ford 6.2L, GM 6.2L, Ram 5.7L, and Tundra 5.7L; it got pretty good fuel mileage. Heck, just looking at Fuelly.com would show you that if you got a 17.5 mpg average then you are doing better than even today's V8s that now have MDS and 8 speeds since most of those are getting between 16-17 mpg average.

It's more of you said my 2012 EcoBoost did better than today's V8's with MDS and 8 speeds.

I showed that was false. Ford didn't reinvent the wheel with the EcoBoost. They unfortunately gave it a misleading name.

My parents traded off their 4cyl ecoboost Escape because it could barely touch 20mpg. Their Jeep Cherokee gets 25-26.

It's amazing how your story changes... :eyeroll

My point was that when the Ecoboost came out, it did deliver better mileage than other V8 engines while also having better performance and capabilities than most V8s at the time. It was outperforming the big GM 6.2L (non Ecotec) while returning better fuel economy than the substantially less powerful GM 5.3L (non Ecotec) which had the best V8 fuel economy at the time.

 

[MANual_puller]

Add the fact that Fuelly has the 3.6L at averaging 20 mpg and the Ecodiesel averaging 22.5 mpg, the fuel cost would be more for the Ecodiesel given prices being at $1.50 for regular and diesel being $.20 more. I can see paying more for better performance and more capabilities even if the fuel mileage was less, but not for less performance and less capabilities.

What's stupid about this is that back in the late 90s and early 2000s a diesel in a 3/4 ton could get that 22.5 mpg with a little tuning. Nowadays that's "eco" in a half ton. Utterly stupid what the epa has done to the auto industry. Just my 2 cents. That ecodiesel could do amazing things if they would just quit choking the diesels. Ponying up extra cash for the ecodiesel and then having to shell out more cash to delete it just to get the cost/mile comparable with other engines seems silly. One would have to drive it a long time for that to pencil out. Also, anyone heard of an ecodiesel being successfully deleted? That's the next problem with it lol

 

[MANual_puller]

It's more of you said my 2012 EcoBoost did better than today's V8's with MDS and 8 speeds.

I showed that was false. Ford didn't reinvent the wheel with the EcoBoost. They unfortunately gave it a misleading name.

My parents traded off their 4cyl ecoboost Escape because it could barely touch 20mpg. Their Jeep Cherokee gets 25-26.

Absolutely. So the ecoboost has a lower bore x stroke displacement. Doesn't mean anything because it displaces more air by using a turbo. Actual displaced air is comparable to most v8 engines on the market. Gas engines need a constant a/f ratio or they burn up. The only time the ecoboost gets "better" mileage is when you can keep it out of boost. But mds cuts down displacement in a v8 too. Ironically you would be underneath boost with an ecoboost and in mds with a hemi under the same exact driving conditions. Both technologies do the same thing: progressive displacement. The problem is that trucks are too heavy to utilize the technologies. You're rarely in fuel saving mode with either. You can't overcome physics. That's why in the real world they get about the same mileage and guys that turn off mds in their hemis see little difference.

 

[SouthTexan]

It's more of you said my 2012 EcoBoost did better than today's V8's with MDS and 8 speeds.

I showed that was false. Ford didn't reinvent the wheel with the EcoBoost. They unfortunately gave it a misleading name.

Take a look at what I said in that whole sentence especially this part.

Heck, just looking at Fuelly.com would show you that if you got a 17.5 mpg average then you are doing better than even today's V8s that now have MDS and 8 speeds since most of those are getting between 16-17 mpg average.

I was referring to the 17.5 mpg you stated earlier which I thought was average and not highway saying that IF that is what you are then you are doing better than today's trucks. You even corrected me in another post saying that that was your highway mileage and not average so why are you now stating that I am meant otherwise?

 

[SouthTexan]

Absolutely. So the ecoboost has a lower bore x stroke displacement. Doesn't mean anything because it displaces more air by using a turbo.

At full boost the effective displacement of the Ecoboost is 7.0L. Some see that and think that is throughout the while engine speed, but that is only at full boost which at around 2,500 rpm and carries it for a few hundred rpms. This is why the 3.5L Ecoboost is making more horsepower and torque than even the 420hp and 460lb-ft GM 6.2L does at 2,500 rpm. It slowly tappers off with less effective displacement after that since the turbos are very small for quick spool up times and are not made for high rpm power.

 

[MANual_puller]

At full boost the effective displacement of the Ecoboost is 7.0L. Some see that and think that is throughout the while engine speed, but that is only at full boost which at around 2,500 rpm and carries it for a few hundred rpms. With is why the 3.5L Ecoboost is making more horsepower and torque than even the 420hp and 460lb-ft GM 6.2L does at 2,500 rpm. It slowly tappers off with less effective displacement after that since the turbos are very small for quick spool up times and are not made for high rpm power.

Absolutely correct. You're rarely going to be at full boost so actual displaced air is comparable. If the ecoboost sat at max boost most of the time then it would get terrible mileage. The point I'm trying to make is that the big 3 all use a progressive displacement technology in their half ton trucks but it doesn't seem to help much in the real world and they all wind up with roughly the same actual mileage in the end because of physics. It takes a certain amount of energy to move a heavy parachute. Gas is the energy source. Physics make the fuel mileage debate pointless.

 

[derag2]

The truck on the billboard has what looks like the eco boost badge on the outside.

 

[drittal]

The problem is that trucks are too heavy to utilize the technologies. You're rarely in fuel saving mode with either. You can't overcome physics. That's why in the real world they get about the same mileage and guys that turn off mds in their hemis see little difference.

speed and aerodynamics really come into play. F150 lost 700lbs to gain .6mpg. If I drive 50 I can get almost 23 (22.89 winter fuel, hand calc) in 6.4. If I drive 80 I hope for 15.

 

[MANual_puller]

At full boost the effective displacement of the Ecoboost is 7.0L. Some see that and think that is throughout the while engine speed, but that is only at full boost which at around 2,500 rpm and carries it for a few hundred rpms. This is why the 3.5L Ecoboost is making more horsepower and torque than even the 420hp and 460lb-ft GM 6.2L does at 2,500 rpm. It slowly tappers off with less effective displacement after that since the turbos are very small for quick spool up times and are not made for high rpm power.

I also find it funny that with a peak displacement of 7.0l they could only muster 30 more hp than my hemi......could you imagine what a 7.0l hemi would lay down for numbers?? Just saying......

 

[SouthTexan]

Absolutely correct. You're rarely going to be at full boost so actual displaced air is comparable. If the ecoboost sat at max boost most of the time then it would get terrible mileage. The point I'm trying to make is that the big 3 all use a progressive displacement technology in their half ton trucks but it doesn't seem to help much in the real world and they all wind up with roughly the same actual mileage in the end because of physics. It takes a certain amount of energy to move a heavy parachute. Gas is the energy source. Physics make the fuel mileage debate pointless.

True and I agree here, but my whole point initially was that it did actually got better fuel economy other V8s when it came out in 2011 before all these 8 speeds and direct injected V8s that require higher octane fuels came out. So it was more "Eco" while having more "boost" than other high displacement towing V8s it's performance compared to at the time it came out. Since then, all manufacturers have improved their trucks to get better fuel economy which is what happens as things progress and get better. It is like these manufacturers keep playing leap frog with each one getting better with each update. That is not a bad thing though.


Although in reference to displacement being used, I would wager that low end torque would be more usable in more transmission gears and speeds than higher end torque. Higher end torque is not usable in as many gears as lower end torque is in normal driving especially when towing. Take the example of the Ram 2500 6.4L 3.73 in a usable torque comparison to something that has lower peak torque like the F150 3.5L EB 3.73 . Look at the max road speed you would have to be at in each gear in order to be able to utilize each engines peak torque.


Ram 6.4L 429 lb-ft @4,000 rpm 3.73 gears stock 33 4x4 inch tires
1st: 33 mph
2nd: 57 mph
3rd: 75 mph
4th: 105 mph
5th: 128 mph
6th: 167 mph

F150 3.5L EB 420lb-ft @2,500 rpm 3.73 gears stock 32 4x4 inch tires
1st: 15 mph
2nd: 27 mph
3rd: 42 mph
4th: 56 mph
5th: 77 mph
6th: 93mph


This is also considering that the 6.4L has a low peak rpm compared to most other N/A V8s out today. Which one do you think you be able to utilize the peak torque more often in normal driving and towing if needed?