@SteveRacer - I agree with the addition to my answer, but I was thinking it could use something to the effect of plastic deformation ... just to really throw a monkey wrench in the works. Plastic?? Aren't we talking about metal here??

@Pᴀᴜʟsᴛᴇʀ2 Exactly! But I've learned from my professor days that if I make my answer too absolutely correct, eyes glaze over and I lose the audience. It has always fasten-ated me how brilliant mechanical engineers have absolutely no clue as to how fasteners really work.

25 years ago my ex (a brilliant mechanical engineer) took me in 20 minutes from "I know everything" to "My God, I know nothing." Clamping force, stretch, plastic deformation, critical torque, anti-seize, left-handed threads, galling, bolt grade, thread pitch... the debate will go on forever, but it amazes me how old wive's tales (but not my wife) will always seem to trump the years of knowledge that people who design fasteners for a living repeat ad nauseum...

Oh, and while it was pretty cocky of me to edit your answer, I thought it more subtle than challenging minutia with a comment to an otherwise solid response.

Sigh. Getting trolled is not how I really want to start my day.

@BobCross Good morning. What happened?

Standard comment jibber jabber ... "Please take open ended discussions to the chat". We've been around the loop a few times now.

At least the princely salary that I get for being a mod makes up for it.... Hey, wait!

No one is trolling you, Bob, don't be so paranoid. I posted a completely rational comment explaining why your answer is inadequate and you just deleted all my thoughts instead of improving your answer. Twice. The comment section is there for exactly that, I have no idea what kind of open ended discussions you are talking about. While I respect and appreciate your enormous contribution to this site, that is just not acceptable.

An open ended discussion is just that: it doesn't reach a conclusion. What is the action to be taken? If there's a continual back and forth without reaching an end state, that's open ended. It detracts from the value of the actual Q&A format.

I'm always going to take the position of: data wins, beating theory. That's the rebuttal to any abstract rhetorical example.

I merely pointed out that you are not taking the correct approach to answering the question in order to encourage you to improve it. The "data" from your "data wins" was practically irrelevant, no one measures long term fuel consumption by looking at real time consumption values for a few seconds and making conclusions from them.

Instead of defending your position or reconsidering your answer you just claimed that it was an open ended discussion and deleted the comments. There was no discussion and there was nothing open ended about it.

The subject question is about rapid acceleration's effect on fuel consumption. The only way to measure due consumption is with real time data. The OBD is the most convenient way to collect that data. The fact that acceleration takes a short time is a circular definition. It only takes a little while to get up to speed. Ergo, you collect data in sets that are only a few seconds long.

The question is about rapid acceleration's effect on long term fuel consumption. Roughly: what is more economical, accelerating slowly to avoid wasting a lot of fuel in a short time or accelerating quickly to get to the highest gear and reach an economical cruising speed as soon as possible.

What exactly are you going to do with your few second long data sets of real time fuel consumption gathered during periods of acceleration if you need to know how much gas your truck will guzzle in 100km of mixed conditions?

Are you going to measure the periods of time accelerating and integrate the real time consumption values during these periods for comparison?

Are you arguing that the fuel consumed during the acceleration to speed is irrelevant to the question? Or are you arguing that the acceleration phase takes a short time and so accounts for a short period in a larger dataset?

Fuel consumed during acceleration is most relevant as long as you calculate the actual amounts during the phases instead of just glancing at the numbers and saying "yup, that's definitely a lot". However it is only a part of the dataset. I'm highly interested in the full method that you used to conclude that accelerating slowly is more fuel efficient in the long run than accelerating briskly.

You didn't provide much detail besides "you can see instantaneous fuel consumption via OBDII" and "Jeremy Clarkson said so".

Now you're asking a different question. If you reread the original, it was talking about a single long road in order to avoid the city driving stop and go scenario. If you would like to investigate a specific driving scenario and how much a different driving style would matter, I suggest that you go ahead and ask it.

How is the question different? I didn't mention city or long roads and we are still talking about fast vs slow acceleration for getting to cruising speed.

I recommend that you ask a new question with all the details that you feel are appropriate. I'd include specifics like gas vs diesel, turbo vs supercharger vs NA. You could also include a specific route. That would give you a chance to investigate all the aspects in the context of a fully specified situation.