6000 Mile TT Towing Report
11-24-2012, 11:23 AM
#21
Senior Member
If the 3.7 was able to go as fast as I wanted, or could safely go, and it has lower Brake Specific Fuel Consumption that the 5.0, how would the 5.0 do it more efficiently? That is an old myth going back to the ****tier base engines having a lower level of engineering, and inferior transmissions. Not applicable to this scenario. Remember, I was getting the mileage benefits of the more efficient engine the vast majority of this trip, running 2400 rpm in 5th. Not bashing the 5.0, it is just not as efficient as the 3.7.
I test drove identical trucks, all 3 models, and the average over a mile on the same day, same stretch of road, the 3.7 was the most efficient, EB next, with the 5.0 about 10% back of the 3.7 @ 70 mph.
That's my thoughts as well. I have never worn out an engine, and I (especially when I was a little younger), treated an engine as abusively as imaginable. The only time I abused an engine to its limit was on successive 1/4 miles with a modded Dodge 318, and I overheated the oil. It developed a light rod knock. Consensus at the time was the oil temp wat the issue.
This trip was a on-off. 80% of 15-20 000 miles a year is usually highway travel, and on that alone the 3.7 saves over 10% on fuel over the 5.0 @ 70 mph.
I test drove identical trucks, all 3 models, and the average over a mile on the same day, same stretch of road, the 3.7 was the most efficient, EB next, with the 5.0 about 10% back of the 3.7 @ 70 mph.
That's my thoughts as well. I have never worn out an engine, and I (especially when I was a little younger), treated an engine as abusively as imaginable. The only time I abused an engine to its limit was on successive 1/4 miles with a modded Dodge 318, and I overheated the oil. It developed a light rod knock. Consensus at the time was the oil temp wat the issue.
This trip was a on-off. 80% of 15-20 000 miles a year is usually highway travel, and on that alone the 3.7 saves over 10% on fuel over the 5.0 @ 70 mph.
Also your test drives were unloaded. Loaded fuel economy isn't comparable. It also seems fairly unanimous that the 5.0 returns better fuel economy under heavier loads than the EB. Not to say the 5.0 out tows the eb, just uses less fuel under load.
11-24-2012, 11:40 AM
#22
And another point that I think you're missing is that 300hp in one truck can respond completely different than 300hp in another truck. Take a look at the dyno graphs and see where each makes 300hp. More importantly for towing, you should be comparing torque PROFILES not peak hp or torque numbers. To argue that the 3.7 makes the same 300 hp that the 5.0 makes is not a good argument at all. Sure, you can say its true because they do both make 300 hp but the delivery of that 300hp and where it makes it in the rpm range makes all the difference in the world. I would rather pull with a truck that made peak tq of 350 ft lb but made it at 2000 rpm than one that made a peak of 800 at WOT but only 250 at 2000. The fact that the 3.7 had to pull 2nd at redline tells me all I need to know.
I'm not trying to slam on you, I just don't think you completely understand what you're talking about. Even that sounded like a ****ty thing to say but I don't mean it that way.
I'm not trying to slam on you, I just don't think you completely understand what you're talking about. Even that sounded like a ****ty thing to say but I don't mean it that way.
11-24-2012, 11:47 AM
#23
Senior Member
Thread Starter
1) 6K is not redline.
2) I fully understand. I also fully understand that the entire post (about a big engine magically becoming more efficent under load) was based on outdated assumptions. Ignoring BSFC and other things. There is a good chance the 3.7 generates more horsepower at in 5th, than the 5.0 in 6th, and uses less fuel while doing so. BSFC is not RPM dependent, it varies based on RPM obviously, but that is not the end all of the discussion. I doubt the 5.0 would tow my trailer in 6th, the 5.0 is not some torque monster.....
To put it simply, the 3.7 is more efficient from a starting point, I see no reason under moderate load, why the efficiency curve would go under the 5.0's. Ignoring operation above 4000 rpm of course, as full throttle enrichement at those RPM's can throw things out of whack.
I also the point that if 300 hp does the job, (and I wasn't full throttle at 6Krpm anyhow), then why buy the 5.0? Because I feel sorry for revving it? not me. If it could have pulled 3rd, that would have helped, but I don't base my engine choice on the hardest hour the truck is likely to face in it's lifetime.
2) I fully understand. I also fully understand that the entire post (about a big engine magically becoming more efficent under load) was based on outdated assumptions. Ignoring BSFC and other things. There is a good chance the 3.7 generates more horsepower at in 5th, than the 5.0 in 6th, and uses less fuel while doing so. BSFC is not RPM dependent, it varies based on RPM obviously, but that is not the end all of the discussion. I doubt the 5.0 would tow my trailer in 6th, the 5.0 is not some torque monster.....
To put it simply, the 3.7 is more efficient from a starting point, I see no reason under moderate load, why the efficiency curve would go under the 5.0's. Ignoring operation above 4000 rpm of course, as full throttle enrichement at those RPM's can throw things out of whack.
I also the point that if 300 hp does the job, (and I wasn't full throttle at 6Krpm anyhow), then why buy the 5.0? Because I feel sorry for revving it? not me. If it could have pulled 3rd, that would have helped, but I don't base my engine choice on the hardest hour the truck is likely to face in it's lifetime.
Last edited by isthatahemi; 11-24-2012 at 11:55 AM.
11-24-2012, 11:49 AM
#24
Senior Member
Thread Starter
The EB drinks fuel because it is generating more power, and FI requires a slightly richer mixture, hurting BSFC.
Last edited by isthatahemi; 11-24-2012 at 11:52 AM. Reason: spelling
11-24-2012, 11:52 AM
#25
Inebriated 4 ur safety
Yeah, but as he was saying he was not going up hills or had headwind most of the trip so the 3.7L was perfect for him most of the trip. It was a few instances that he had to be in the upper rpms so a majority of the time a 5.0 or EB would be the inefficient engine choice for what he was doing. Same reason why they 5.0ers don't get the EB because they don't tow all the time so that extra pulling power is not needed. They probably could use the power of the EB on a few occasions but for the most part the 5.0L is more than fine.
As for the EB getting worse loaded fuel mileage. I would have to say nay nay to that from my own real world experiences. I pulled almost identical loads (8,000lbs 5.0 2wd Scab 3.55 & 8,500lbs EB 4wd Screw 3.55) on the same stretch of I-10 from SA to Houston with the same no wind situations and the cruise set at 65 mph the whole way. The EB got almost 1 mpg better by hand calculations. I will say that I do prefer the 5.0s engine braking over the EB though.
As for the EB getting worse loaded fuel mileage. I would have to say nay nay to that from my own real world experiences. I pulled almost identical loads (8,000lbs 5.0 2wd Scab 3.55 & 8,500lbs EB 4wd Screw 3.55) on the same stretch of I-10 from SA to Houston with the same no wind situations and the cruise set at 65 mph the whole way. The EB got almost 1 mpg better by hand calculations. I will say that I do prefer the 5.0s engine braking over the EB though.
11-24-2012, 11:59 AM
#26
Senior Member
Thread Starter
I would rather the thread not degenerate into the typical compensatory "why a bigger engine is better" type of thing. To do that would miss the entire point of me posting a towing review of the 3.7. It did it, and it did it efficiently. Speculating that a larger less efficient engine would have maybe matched or beaten it for less than 2% of the trip is not the point. The other 98% of the time, I have no doubt the 3.7 is more efficient. I have owned 7 trucks, and had 2 company vehicles, both 1 ton. i have yet to come accross a scenario where a properly geared smaller engine ever gets worse mileage than the larger on. As for the noise / abuse issue, well that is "to each his own".
11-24-2012, 12:01 PM
#27
Senior Member
Thread Starter
....
As for the EB getting worse loaded fuel mileage. I would have to say nay nay to that from my own real world experiences. I pulled almost identical loads (8,000lbs 5.0 2wd Scab 3.55 & 8,500lbs EB 4wd Screw 3.55) on the same stretch of I-10 from SA to Houston with the same no wind situations and the cruise set at 65 mph the whole way. The EB got almost 1 mpg better by hand calculations. I will say that I do prefer the 5.0s engine braking over the EB though.
As for the EB getting worse loaded fuel mileage. I would have to say nay nay to that from my own real world experiences. I pulled almost identical loads (8,000lbs 5.0 2wd Scab 3.55 & 8,500lbs EB 4wd Screw 3.55) on the same stretch of I-10 from SA to Houston with the same no wind situations and the cruise set at 65 mph the whole way. The EB got almost 1 mpg better by hand calculations. I will say that I do prefer the 5.0s engine braking over the EB though.
11-24-2012, 12:04 PM
#28
I fully understand. I also fully understand that the entire post (about a big engine magically becoming more efficent under load) was based on outdated assumptions. Ignoring BSFC and other things. There is a good chance the 3.7 generates more horsepower at in 5th, than the 5.0 in 6th, and uses less fuel while doing so. BSFC is not RPM dependent, it varies based on RPM obviously, but that is not the end all of the discussion.
To put it simply, the 3.7 is more efficient from a starting point, I see no reason under moderate load, why the efficiency curve would go under the 5.0's. Ignoring operation above 4000 rpm of course, as full throttle enrichement at those RPM's can throw things out of whack.
I also the point that if 300 hp does the job, (and I wasn't full throttle at 6Krpm anyhow), then why buy the 5.0? Because I feel sorry for revving it? not me. If it could have pulled 3rd, that would have helped, but I don't base my engine choice on the hardest hour the truck is likely to face in it's lifetime.
To put it simply, the 3.7 is more efficient from a starting point, I see no reason under moderate load, why the efficiency curve would go under the 5.0's. Ignoring operation above 4000 rpm of course, as full throttle enrichement at those RPM's can throw things out of whack.
I also the point that if 300 hp does the job, (and I wasn't full throttle at 6Krpm anyhow), then why buy the 5.0? Because I feel sorry for revving it? not me. If it could have pulled 3rd, that would have helped, but I don't base my engine choice on the hardest hour the truck is likely to face in it's lifetime.
The second part in bold makes no sense to me. If it is not rpm dependent then why does it change with rpm?
I would like to hear from any 5.0 or EB owner that ever got 6 mpg towing a 3500 pound TT. I tow a 5500 pound enclosed 7x18 with my EB. I can set the cruise at 65 in 6th and get 13 easily. It also rarely downshifts and if it does, it's never below 4th and 85% of the time it downshifts its to 5th.
11-24-2012, 12:08 PM
#29
I also the point that if 300 hp does the job, (and I wasn't full throttle at 6Krpm anyhow), then why buy the 5.0? Because I feel sorry for revving it? not me. If it could have pulled 3rd, that would have helped, but I don't base my engine choice on the hardest hour the truck is likely to face in it's lifetime.
11-24-2012, 01:24 PM
#30
Senior Member
Originally Posted by MXD
There is actually no chance. The 3.7 makes the same power in every gear. It doesn't make more in 5th than it does in 6th. Power is rpm dependent not gear dependent. Therefore, the same is true of the 5.0. The difference is that the 5.0 makes substantially more power at lower rpm's which allows it to up shift and conserve fuel. If you are arguing that with each at 4000 rpm they will burn the same fuel or the 3.7 will burn less, maybe. I don't know the answer to that but what I do know is that when the 3.7 has to pull at 4000 rpm in 3rd or 4th the 5.0 or EB are likely cruising in 6th at 1700.
The second part in bold makes no sense to me. If it is not rpm dependent then why does it change with rpm?
I would like to hear from any 5.0 or EB owner that ever got 6 mpg towing a 3500 pound TT. I tow a 5500 pound enclosed 7x18 with my EB. I can set the cruise at 65 in 6th and get 13 easily. It also rarely downshifts and if it does, it's never below 4th and 85% of the time it downshifts its to 5th.
85 mph up the Coquihalla hwy (see the tv show highway to hell) for an 1 1/2 hours until a trailer tire separated.
2011 FX4 Ecoscrew 6.5 box. Backed off at the summit and drove the rest of the way (300 miles) at 60 mph getting 9 mpg US.
Engine didn't even work hard, get hot. Mostly half throttle in 6th gear. Tons of torque, but will drink if used.