This is true. Tesla uses a Scalar of 0.747 to scale its raw results from the two UDDS and FTP cycles, while Ford uses the traditional 0.7 number. The Model Y uses this 0.747 value, and the 2021 Model 3 a very similar value, and it comes from the heat pump, which gives better performance on the SC03 and FTP 20F cycles. That allows them (per EPA rules) to use that calculated scalar, which folds in those other "5-cycle" results.
EPA range = (0.55*UDDS+0.45*FTP)*Scalar
But please note that the Mach-E does NOT have a heat pump (at least from the first link in my quick Google search). So it will do
worse in cold weather than Model Y and 2021 Model 3.
Note that before 2020 Model Y, Model 3 used about 0.703 for the scalar - because it did not have a heat pump. So relatively little inflation due to this factor in prior years.
That's true, but the information on the exact RAW (AC) efficiency is published by the EPA.
Download Fuel Economy Data
Here's the comparison. You can see that in
raw (AC) efficiency, the Model Y is about 20% more efficient than the Mach-E AWD. Not the 27% you quoted. This 7% difference is due to the scalar difference of 7%.
View attachment 619586
If you want to dive into the exact DC efficiency differences (which are more relevant for range, but to be honest AC-DC conversion losses (which are about 12% for Tesla) are likely about the same for all manufacturers so don't really need to go there), you have to go to the raw EPA docs:
Basic Search | Document Index System | US EPA
This is where I disagree with you. We'll use just Highway numbers here.
After removing the effect of the scalar (scale EPA highway 306 mile Model Y result by 0.7/0.747), the Model Y in optimal no heat pump conditions, would get 287 miles, which is still more than the Mach-E AWD highway result, at 255 miles, before they voluntarily lowered it to 250 miles. (All these numbers are in the spreadsheet linked in the first link.)
So I think the range advantage likely goes to Model Y here. In California range will be close for the two vehicles, and at
freeway speeds the difference will be smaller in absolute terms than the 255/287 results from above, because the aero losses will dominate even more than they do in the EPA testing...though the Mach-E seems to do slightly poorly on aero...so absolute range gap might not tighten much (and %-wise it might even be a larger difference).
I'd expect about 230-240 miles max at 80mph for 100% to 0% for Model Y, in optimal conditions. And about 210-215 miles for Mach-E at 80mph in optimal conditions.
But in colder climates, the range advantage I think will very clearly go to Model Y with the heat pump.
And as covered, the efficiency advantage will of course be huge (which is important for charging time, assuming you could even get a 150kW charge for the Mach-E - and 250kW charging is not available). That affects charge time, a lot!
This affects overall wall-to-wheels efficiency, and potentially by a large amount depending on how much you drive, but does not affect your driving range.