3LR (RWD) vs.P3D Efficiency Comparo (Imperfect)

[SageBrush]

We can pull out the energy for the elevation rise:

105kg * 9.8m/s^2 * 275m = 283kJ = 79Wh

Assuming 50 mi the total difference between the two vehicles was 650Wh, so the rise only accounts for about 12% of the difference, but it makes the difference between the two vehicles [for a round trip or otherwise net zero elevation change] a lot closer to 4%. Nice, I'd resigned myself to lose at least 15 miles off full highway range and this is slightly below that (w/the caveat that you have to watch on uphill trips).

Math looks right, but is 105 Kg the correct difference between an LR and the 3PD models ?
We should probably also include weight differences between the drivers and luggage.

 

[ohmman]

mod note: title amended.

 

[ℬête Noire]

Math looks right, but is 105 Kg the correct difference between an LR and the 3PD models ?
We should probably also include weight differences between the drivers and luggage.

I used the two Model 3 curb weights that come up with Google, 3,838 and 4,072 lbs. (4072-3838)/2.2 = 106.4kg (rounding is balanced by me rounding the 900ft conversion up to 275m from 273 and change)

Those sounded right, although I didn't try track down the full citation.

Yeah, the mass difference from RWD to AWD (although on the high side of the range we see in the Model S) isn't that big, and it is true that adding a modestly portly passenger (like myself!) could easily make up that much difference, or more. I don't know @ForeverFree 's wife, and perhaps one of them was packing notable luggage/cargo of some sort, but judging from his avatar picture he's not a Sumo wrestler, plays on an NFL front line, or anything like that so not sure that level precision would make meaningful of difference here?

Easily the biggest unknown here is whatever drag reduction there might have been from drafting. However given the low drag nature of the Model 3, the lead car would have created a lot smaller envelope for that to matter than if the lead Model 3 was itself following a 3rd party vehicle at a similar distance.

 

[SageBrush]

judging from his avatar picture he's not a Sumo wrestler

True enough -- if that is him.

 

[Jedi2155]

For all intents and purposes, unless they're within 30 feet of each other at > 50 mph, I'd consider there to be effect to be negligible.

I haven't used Model 3 autopilot on the highway yet (only experience was during my P3D+ test drive on surface streets) so I don't know the follow distance.

I've been practicing hyper-miling techniques (Following Wayne Gerdes since 2006-07). Drafting behind cars don't offer much benefit past 30 feet. You might get To me, 3 car lengths is roughly 60-100 feet on the freeway. The best vehicle to hypermile behind is of course a semi, but that doesn't sound like the case here. At some distance the drafting becomes turbulence (net negative) rather than a positive or neutral impact.

 

[ForeverFree]

Great post! I suppose the LR had slightly more wear on the tires too? I think the Wh/mi comes down after the first 1-5k miles as the newness comes off the tires.

Good point. And, yes, this is a non-trivial effect.

 

[ForeverFree]

Need to make sure tire pressures are the same as well.

They were.

 

[ForeverFree]

It would also be helpful if Forever could update his original post to change references from 3D to 3LR or RWD. Would prevent confusion from the first post onward!

Am I able to edit, still??

 

[ForeverFree]

True enough -- if that is him.

Definitely not sumo. More Mr. Miyagi-sized ...

 

[ohmman]

It would also be helpful if Forever could update his original post to change references from 3D to 3LR or RWD. Would prevent confusion from the first post onward!

Am I able to edit, still??

Done. The site limits edits to within a short period after posting, but I was able to get in there and clean it up (I hope).