MPG gain in sport vs. Its inherent extra wear on components

[ControlNode]

There are many non-linearities in wear equations. Lower rpm does not always equal lower wear, and conversely, higher rpm does not always equal higher wear. The main and rod-end bearings are hydrodynamically supported, and the slower the relative speed, the lower the film strength. The higher the speed, the higher load they can support. At most operating speeds, there is literally no metal-to-metal contact, as the surfaces are supported a layer of oil. The wrist-pin bearings and the piston skirt are reciprocating bearings, and are subject to more wear at higher loads, because the reversing motion allows film penetration and causes metal-to-metal contact. Does higher rpm cause more or less wear on these bearings? I'm sure it's not a simple linear relationship, and I'd expect throttle settings and engine load both play more of a part than the absolute speed.
Listen to the machine, and you can usually tell when you are hurting it. My motor is MUCH happier between 1500-2500 rpm (S mode) than it is between 1200-2000 rpm (D mode). That 300 rpm makes a huge difference in vibration and harshness. Smoother is better for almost any machine.

I've always been a 4 cyl runs at close to 2k or more. Only really below 2k on when cruising on level or decline road, and no lower than ~1750. I've been using the manual lockout of the upper gears so that the rpm is where I'm comfortable and I never really feel like the engine is lugging for a moment before it thinks to downshift if I encounter a mild incline.

Tomorrow I'm pulling a trailer to my daughter's house and will be using tow mode, interested to see how that differs from normal Drive.

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[CB750F]

Maybe its only better in "S" if you compare "D" and "S" with both running WOT all the time.
That might make sense

@Floyd ,

I'm sure your onto something, WOT it is for me, all day long!

@MXGOLF , I guess were suckers but it could be worst, could be " I broke a rod" worst.
@Msfitoy , Your truck is not even in my ball park ?

 

[JesseS]

I think its funny that someone would think you would get better 'mpg' in 'sport' mode seeing as how those two terms are mutually exclusive. If you want better MPG stay in 'D' and feather the pedal.... but that's no fun.

 

[FunInTheSun]

my point is...I'm not in the hospital today....I'm not doctor and dont know whats going on inside me. so tomorrow I could be. or I could be dead or whatever.
So yes, I'm functioning today, but something might not be right. It has yet to be discovered.

to say I have no problems, and knowing the history of abuse I've put onto my body....you cant say I have no problems.

But what does your fuel economy look like? Can you still burn rubber? No tell-tale squeaks and creaks going over bumps? Any notable leaks? Overheating or smoking at stop signs? (OK, I'll stop, this is clearly getting out of hand...)

 

[Langwilliams]

Since I've retired an I'm not buying a tank of premium every week my mileage went down a few do to running a lot more around town but the tank lasts close to 2 week. I changed the display screen to the big digital speedometer so I no longer see the MPG. I've learned to not stress over it an enjoy the truck as a truck and an occasional stop light bandit. When I did 11-12 miles each way on the highway to work an home I wanted to see that 22+ avg. With the winter gas, bigger tires, colder temps an level kit right now I'm in the high 17's but no longer worry about it. If I were paying California prices I probably would try to stretch it out of principle.

 

[BassRanger]

Maybe I got lucky, but my truck drives great in Drive. I use tow mode to....... ?...... tow, and I don't use sport mode because I hate the hyped pedal response and rev hang. Other than 1 or 2 hard shifts after cold start, trans is smooth. Usually don't have a clue what gear the truck is in unless I pull up the gear display.
Never feel like the truck is turning too low of an RPM. If I need accelerate, press the throttle pedal down and it down shifts.

As far as the extra wear from higher RPM, think about it this way. There are plenty of vehicles offered with different rear end gear ratios. The vehicles with numerically higher ratios will inevitably cycle more over the life of the vehicle. To my knowledge, there haven't been any trends of premature wear related failures of vehicles that could be traced to higher rear end gears.

 

[D Fresh]

The truck is adapting just fine and though that lugging (in D) may seem uncomfortable and such its not gonna hurt a thing.

You should not give mechanical advice. Lugging is bad for any engine. Let alone a small displacement turbo engine.

What I don't understand is the adversity to the fact that higher rpms do not necessarily translate into less efficiency. Its science. While the number of situations where more rpm does equal less MPG may outnumber the situations where it equals more... it's certainly not the rule... especially with turbo applications.

2000 rpm with no boost would likely be more efficient than 1500 rpms while under boost. Load spools turbos. Turbos use gas. Utilizing higher rpms, again, brings the motor into a range where its naturally producing more torque. A motor making more torque is going to be experiencing less load than one making less.. ergo less boost.. ergo improved economy.

I have no skin in this argument weather or not sport actually grants better fuel economy, so don't take me as defending the people who claim it does. They could very well be full of shit.

I'm simply theorizing about if these people aren't full of shit about their claims... and their specific driving situations do indeed see better efficiency at the higher rpm sport gives them... is the million more rpm the motor would spin over its lifetime worth the measly amount saved on gas.

Your point has merit. But as always there is a point of diminishing returns.

The way I drive Tow gets me 1.5 mog better than D. But S tanks it all together.

 

[D Fresh]

lets be real....lugging is 100% on the driver.
if you are in a situation, lets say high gear puttering in the middle lane and you roll up on a slow vehicle, then mash the pedal to pass him....you did that. you put your vehicle into that situation.

theres a multitude of things you can do as a driver to avoid it. pick one of them, or all of them.

LSPI is a different story, no one can predict if and when it'll happen to your engine, any more than we can predict whether a salty seagull will drop a toxic turd on our heads.

hopefully if LSPI destroys your engine, you still have a warranty.

otherwise, carry on, drive your damn truck

LSPI is a direct cause of lugging your engine.

Of course it's on the driver. But when the vehicle is predispositioned to do it, this becomes more difficult.

The shift pattern in D is definitely not preferable in that regard.

 

[Kyp317]

I drive about 400-425 miles a week, mostly just going to work & back. I tried 2 weeks driving in each mod, I think I drive pretty conservative & use cruise control large portion in the drive time.

I get about 22.7mpg in D
20.6mpg in Tow
19.5mpg in Sport
The vehicle claims little better than those numbers but those are off my own tracking. I like the feel of Tow mode the most but I drive so much I usually go for the better mpg lol.

 

[puckdodger]

I drive in whatever I feel like at that particular moment. D, S, and Tow all have their uses. And I also try to avoid the lugging while not worrying too much about whether this or that particular revolution of the crank is gonna be the one that cracks the engine wide open. It is quite the fine line I dance on while operating this beast ?

IMO proper maintenance and a smooth action on both of the pedals is a key to long life of both engine and tranny, and the brake pads too. My Dad told me once when I was much younger that both pedals cost money to operate, so why pay to get up to speed quickly just to hit the brakes to stop in time for the next red light?

 

[D Fresh]

I drive in whatever I feel like at that particular moment. D, S, and Tow all have their uses. And I also try to avoid the lugging while not worrying too much about whether this or that particular revolution of the crank is gonna be the one that cracks the engine wide open. It is quite the fine line I dance on while operating this beast ?

IMO proper maintenance and a smooth action on both of the pedals is a key to long life of both engine and tranny, and the brake pads too. My Dad told me once when I was much younger that both pedals cost money to operate, so why pay to get up to speed quickly just to hit the brakes to stop in time for the next red light?

Completely agreed. I've never had to dance such a fine line. I think it's the Auto. All of my previous small displacement turbo engines were manuals with the exception of my wife's Legacy GT. And it's 5EAT kept the engine in the powerband.

I think a change in shift pattern would be what I'm looking forward to the most about a future tune.

I've settled in on tow mode as the best available option from the factory, but I'm getting tired of hitting the button everytime.

The AutoStopEliminator folks should make a dongle for tow mode!

 

[Floyd]

You should not give mechanical advice. Lugging is bad for any engine. Let alone a small displacement turbo engine.

Your point has merit. But as always there is a point of diminishing returns.

The way I drive Tow gets me 1.5 mog better than D. But S tanks it all together.

Generalities are always false.

Lugging would be defined at a different RPM for any given engine depending on the load .
I don't think you can "lug" The Ranger in any automatic mode.
Perhaps in manual , by intentionally up shifting under a load? (if it'll even do that?)

 

[puckdodger]

Generalities are always false.

Lugging would be defined at a different RPM for any given engine depending on the work being done. I don't think you can "lug" The Ranger in any automatic mode.
Perhaps in manual , by intentionally up shifting under a load?

It sure feels like lugging at around 1300 RPM.

 

[Doc]

It sure feels like lugging at around 1300 RPM.

Yes it will lug, especially if the engine is not up temp .

 

[BassRanger]

You guys are worrying yourselves about absolutely nothing. How on earth do you lug an automatic transmission? These trucks run on a torque based ECU. Meaning when you push the accelerator pedal down, you are essentially requesting a torque value. The ECU calculates the fuel, spark, throttle position, boost and gear before the throttle blade ever flinches. If you request a torque that can not be fulfilled in the current gear, the truck is going to downshift. You cannot force these trucks into a high load situation at low RPM. If you are at low RPM, high gear then the truck is in a low load situation it's not lugging.

Just because the engine note is low and the NVH is increased at lower RPMs does not mean the engine is lugging. Newsflash, inline 4 engines are not smooth at low RPM. This is not a new concept.

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