Separate names with a comma.
Discussion in 'Model S' started by WestCoastP85D, Oct 27, 2015.
Related to the horsepower concerns of the P85D/P90D?
Check out out...
Think it's smart. Most people don't care and there is no standard way in US to rate EVs on HP anyway.
If you click the Model S header and scroll to the bottom, they've kept them listed there.
How about the P90D saying "Enough horsepower to be the quickest 5 passenger car on the planet"?
There are a lot of factors that make horsepower a bad comparison number. It varies much more non linearly over RPM range in a typical ICE auto, but then is kept in semi-optimal range with a multiple gear transmission. In ICE vehicles the number at the crank is often cited which really has no equivalent for an EV with no transmission. You have to measure at the wheels over speed ranges to get any sort of equivalency - which isn't what usually ends up on the spec sheets.
It is smart to remove the HP. However, I would like to see the 1/4 mile time, which is an additional metric to real life performance data.
Finally. My horses were getting really tired of running on AC.
Maybe my insurance will go down! When they ask how many horse power, I get to say zero.
Haha, they still say 0-60 in 3.1 seconds.
I'm pretty sure the P85D isn't going 0 when it reaches the roll out.
Can't we just go back to measuring in poncelets?
Not to be a buzz kill, but the numbers can still easily be found on the spec page:
That would be delightful.
I keep saying:
Electronics components manufacturers sell their components with spec sheets with graphs in them. Tesla is also selling an electric product. Tesla should put graphs in their spec sheets: a 0-max speed/time graph with multiple colored lines representing initial SOC and temperature of battery listing the quadrants of the worst and best of each of the other two variables.
I mean 20% SOC & 100F battery temperature, 20% SOC & 20F outside temperature, 100% SOC & 100F battery temp, 100% SOC & 20F ambient temp, or something more extreme, as well as peak performance and nominal (so, I guess that's 6 to 8 lines). One graph. Simple to read. Answers all questions. (Well, ok, pick the most question answering battery states to map, including temperature, charge level, etc.). One graph to answer them. One graph to rule them all. One graph is all you need to be aware of. One graph will tell all truths. One graph will be all that you need. Done.
Ahem. That's about 4 variables: road grip & tire grip. But my point remains the same. Just pick the most representative explanatory points, including Nakka and stock, California and Norway, rough asphalt and black ice, and just graph it.
I'm not Tesla so I'm not doing the work of finding the most explanatory states. I'm about to go to bed right now. But most people understand what I mean.
Interesting they put the total HP for the 70D and 85D and the HP of each motor, but they don't just add them up. For the P85D they list the HP of each motor, but don't list the total HP.
Amen! This is indeed the way to do it right.
Only providing the 0 to 60 is just not good enough. This is a good way to frustrate buyers because they might only discover its weak points after buying the car. Just be honest about all characteristics. It's a great car, even including its weaknesses.
Adding them up on P85D gets Tesla into trouble.:tongue:
It's not that hard - HP = watts/745.7 :wink:
There are two relevant old sayings - "HP sells cars, but torque wins races," and "electric motors make maximum torque at 0 rpm"
The real problem is that electric motors aren't good at making horsepower, but HP is the car marketer's main tool. They are great for making gobs of torque, down low, where you want it, but not horsepower. That's because HP depends on RPM.
HP = (torque (ft-lbs) * RPM)/5252
At the instant you mash the go pedal, the motor is making insane amounts of torque, but 0 HP, since the RPM = 0. As motor RPM builds, HP rises if torque stays constant. The problem is that it's hard to keep the motor torque up as the RPM builds, so high RPM HP falls (which is why the S is great off the line but lacks high-speed passing power).
ICE engines can produce lots of torque down low (big displacement V8's, possibly with a supercharger), or go for high HP numbers by keeping the torque up at higher RPMs (small 4 cyl with variable valve timing, 4 valves/cyl, turbos - all keep the engine breathing at high RPM). It's really hard to do both (low RPM torque that doesn't fall off as RPM builds.
What Tesla should do is publish a HP/torque graph. When all the V8 gearheads see the insane low end torque, they'll get it.
Jet engines are rated in pounds of thrust and prop engines in horsepower because the way they output energy is different. I think the same sort of thing applies here between ICE and electric motors. KW is more informative of what an electric motor can output if you know the underlying science, but most people don't and want to have a comparison between ICE and electric they can understand.
Very smart move. Rather than post inaccurate numbers or misleading numbers or misinterpreted numbers, just nix the numbers completely. I like it, the performance should be the only thing that matters.