Model X towing is a joke

Discussion in 'Model X' started by David Green, Aug 7, 2019.

  1. David Green

    David Green Well-Known Member

    Wow, this is really eye opening...

     
  2. brulaz

    brulaz Active Member

    bwilson4web likes this.
  3. bwilson4web

    bwilson4web Well-Known Member

    Thanks. I was watching that YouTube on the TV when my wife came in and decided she wanted to watch something else. So I changed the TV to something she likes only to find I couldn't locate the URL on my Macintosh. Regardless, your link was exactly the one I wanted.

    The flaw in their methodology is the tests were in the reverse order. They should have towed the trailer first to get the load benchmark. They would have had enough energy to complete the load benchmark at the rated speed and return to the SuperCharger. Even if they had a charge limitation that required changing the protocol, they could document it and do the unloaded test with the same profile. When I did my CHAdeMO benchmarks, the CHAdeMO sessions were done first. I could then adjust the SuperCharger test as needed to match the CHAdeMO.

    BTW, I came across this YouTube about recent diesel problems:


    Perhaps we'll see an end of these:
    [​IMG]

    Bob Wilson
     
  4. brulaz

    brulaz Active Member

    I would hope so. But think it'll be a while.
    And it's only a small fraction of big diesel owners that relish the pollution they generate.
    Ours (2016 Ram Cummins) has a squeaky clean tailpipe, and is "California Clean".
    But it still pumps out lots of CO2 when we're hauling our trailer South every winter. About 12 tonnes per year according to my calculations.
    Until a capable electric HD pickup comes out, we're planting trees in the Amazon. https://www.cooleffect.org/
    Better than nothing, and there's no way I'm staying in Ontario all winter!
     
  5. David Green

    David Green Well-Known Member

    Well Bob, TFLC always does their testing the same, empty first, and then towing, this clearly shows an electric truck is going to have a hard time pulling weight efficiently, and let's remember this Model X was he Raven with the Model 3 motors. Towing an empty horse trailer cut their real world range to below 100 miles, is ridiculous, and this was Tesla's latest Tech... Now let's take the 900 wh/mi they averaged with a GCVW under 10000 lbs and scale that up to the Tesla Semi that Elon said would use <2000 wh/mi at 80K GCVW, and 18 tire friction surfaces on the ground instead of 8, and punching a much larger hole in the air... HAHA! Another of Elon's fairy tales, and now we see why there is NO Tesla Semi talk anymore.

    As for this Arse hole with the RAM pickup in your other picture, there is no excuse for stupid. People who would remove their emissions equipment and tune their vehicle like that are like little kids with a small pee pee clearly trying to overcompensate. Its just like people who run around quoting 0-60 times and quarter mile ET's for street cars... Who cares? Certainly not me! I cannot remember the last time I went to wide open throttle from a stop in a vehicle. Like Brulaz, I keep my diesel (s) clean and emissions systems maintained properly on all our trucks and equipment because I believe in doing the best we can for the environment. Although after seeing this Tesla towing test, I have far less faith that the Rivian truck or other EV pickup will be a no compromise towing vehicle (law of physics bite again). I just bought a new pickup (GMC /Duramax/10 speed) so far in the first 10 days it is showing a 25% improvement in fuel economy over my last pickup. I have not towed with it yet, but I will this Saturday, and see how it pulls compared to the old one when I move my Mini excavator over the mountain to our cabin.
     
  6. bwilson4web

    bwilson4web Well-Known Member

    Their testing methodology has too many flaws. A better approach:
    • standard day ~72F, no wind - easily done in the pre-dawn hours
    • three, 10 mile benchmark runs - round trip to starting point at speeds 25-35, 45-55, 65-75
    • plot in Excel with a second order polynomial trend line (Ax**2 + Bx + C) this gives a smooth curve across all speeds
    I'm reminded of how many "good ole boys" who rip-out their emissions equipment only to get worse miles and a short engine life.

    We recently had a the right-wing, American Legislative Exchange Council raise the annual registration fees on our EVs to make up for the lost 'gas tax.' But their real problem is modern vehicles are efficient and getting better. They'll still run out of road money.

    Bob Wilson
     
  7. David Green

    David Green Well-Known Member

    Bob, when you are doing a summer towing test the conditions are the conditions. This is the problem with the way you test, you are trying to show the best possible results, and TFLC is trying to show realistic results in the real world conditions. You may not realize it, but when we need to move something, we need to move it at that moment. No time to check the weather, wind, or other conditions, we just have to go move it. In a diesel pickup loaded at maximum capacity the weather does not even make too much of a difference, hardly noticeable. BTW, my new truck has theoretically 720 miles of range highway and fuels in 5 minutes. I am excited to see the Tesla pickup's range... HAHAHA! If the motors match the Model X raven (model 3 efficiency), but you are punching a bigger hole in the air, and more mass due to added capability (F150 which was Musk's target, has vastly more cargo capability, ground clearance, and towing capacity compared to X) I am pretty well convinced the Tesla pickup, Rivian, and other comers are going to have too many compromises for contractors like me, sadly!.

    As for people removing emissions equipment and netting better engine life, and fuel economy I do not have personal experience, but venture to guess most people who delete, also tune for more power / torque which leads to increased wear of the drivetrain components. Following Gale Banks series on hot rodding a duramax diesel there are several weak links in the engine design that play a factor when you try to add more then 25% output. I do not understand why anyone wants to spend thousands of dollars and add any more then the factory 445 HP 910 Lb Ft, which is plenty for me. My old pickup was slightly heavier and was 397 HP and 765 Lb Ft and I never felt myself wish for more power. The new one is not only more powerful and efficient, it has a 10 speed transmission over the outgoing 6 speed, so it keeps the engine in the better power producing RPM range more of the time (towing test coming tomorrow, over the mountains at maximum rated load 23K GCVW ). I am going to top the fuel on departure and monitor the exact fuel economy towing that load, my old pickup would average just under 10 MPG on this trip with the same load, which is 350 miles total range).

    Yeah, in our state the democrats have gone after the EV's a couple times, they are always trying to raise taxes and generate more revenue. It's a constant around here. Most folks in the counties around where I live have extra discretionary income, so the political leaders are always looking for a way to get more of it.
     
  8. bwilson4web

    bwilson4web Well-Known Member

    In aviation, we start with standard day metrics and apply corrections based on temperature, altitude, speed, and weather. But the foundation starts with Standard Day metrics. Their methodology was flawed and became a waste of time. Still if you choose some other conclusion, it doesn’t persuade.

    Bob Wilson
     
  9. David Green

    David Green Well-Known Member

    For that matter the altitude correction to Sea Level would make the EV look much worse, as the battery / motor sees no decline in performance, but with the lighter air in Denver the poor aerodynamics of the trailer are less of a factor. Yes Bob, I have been involved in aerospace Turbine dynamometer testing and fully understand correction factors, we corrected to sea level, 72 F and 65% humidity, humidity being a huge factor in gas turbine engines. Stand in front of a turbine running at full power, and spray a garden hose of water into the inlet (not too much), when you hit the right ratio its fun to watch the shaft HP increase, and EGT drop. I guess that is why some helicopters have optional water / alcohol injection for hot weather, altitude, and high loading.
     
  10. David Green

    David Green Well-Known Member

    Ok, I got my towing results, first off, man the new pickup truck is sweet, quiet and smooth pulling a load, and the engine braking worked perfect, I did not have to apply any brake pressure on the down grades. I was pulling a 2 axle tilt trailer, and Kubota KX -40 mini excavator, 3 buckets and grade beam, GCW 24306 lbs. I-90 East from Seattle over Snoqualmie Pass, 94 miles on the outbound trip averaged 11.15 MPG, on the return trip (4500lb trailer, no load) averaged 16.89 MPG (better mileage than my old truck got without a trailer). These MPG are net calculated by filling the tank and calculating the difference. The GOM in the truck showed a bit more optimistic, but was within 1 MPG both ways.

    With these results I would say my truck loaded to capacity (24K GCVW) has about a 400 mile range so that should be about the number Tesla is shooting for in their EV pickup. What kind of battery pack will that require? if the efficiency is similar to Model X Raven (hard to believe the Aero will be as good on the pickup) which we know from TFLC with <10K lb GCVW has about a 100 mile range at mile high altitude on flatish ground). Tesla has a ton of homework to do.
     
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