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Perf vs. standard 85kwh power bands?

Discussion in 'Model S: Driving Dynamics' started by ckessel, Jul 11, 2012.

  1. ckessel

    ckessel Active Member

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    I hunted and didn't find a thread that seemed quite right.

    I've heard a couple comments about where the Perf mostly beats the standard 85kwh as being in the 0-30 range. Has anyone really heard about where the Perf beats the standard? For example, how do the both behave in the "passing" band of 50-80 mph?

    I'm thinking, depending on where the Perf shines, it may help me decide if it's worth getting or not.
     
  2. Jason S

    Jason S Model S Sig Perf (P85)

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    For the Roadster the extra power was mostly in the 0-30.

    I don't think anybody really knows for the Model S, but my guess is a much broader power band.

    Would love to see some charts, but I don't think any exist outside of Tesla.
     
  3. VolkerP

    VolkerP EU Model S P-37

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    Check the Model S options page, section "Battery and Performance": The Perf Model delivers 36% more torque between 0-5,000 rpm (that's 0-45mph). The gap narrows to 16% when approaching 5,800 rpm (52mph). There is no data beyond that, but I expect that delivered power is even closer.

    Conclusion: Acceleration will differ the most between 0-45mph.

    To your question regarding passing band of 50-80mph, I expect there will be perhaps 5% more to the Performance model.

    If that tiny bit makes all the difference in the outcome of your passing maneuvers, please get a LEAF or a Volt and send me the cash delta for the Perf - I just saved your life. :biggrin:
     
  4. ckessel

    ckessel Active Member

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    Ok, so check my reasoning on this....

    The specs page says the Perf 1/4 mile is 1.1 seconds faster than the Standard. The Perf 0-60 is 1.2 seconds faster. That tells me that after 60 mph, the Perf must not have any real power advantage over the Standard. The Perf has a 1.2 second gap when both hit 60 mph and doesn't improve on that gap from 60 mph to whatever the final speed is at the end of the 1/4 mile.

    Does my reasoning hold together?
     
  5. Jason S

    Jason S Model S Sig Perf (P85)

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    Reasoning holds.
     
  6. richkae

    richkae VIN587

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    You are mixing time ( 0-60 ) and distance (1/4 mile ).
    The non-perf car will take more distance to get to 60 mph, and then have less distance left to finish the 1/4 mile.

    *If* the acceleration is constant from 0-60 ( it is not ) the perf car will take 194 feet to get to 60 mph.
    Then it will have 1086 feet to go to finish the 1/4 mile. It does that in 8.2 seconds ( 12.6 - 4.4 ) at an average of 90.3 mph.

    The non-perf car will take 246 feet to get to 60 mph, leaving 1034 feet in the 1/4 mile. It does that in 8.1 seconds ( 13.7 - 5.6 ) at an average of 87 mph.

    The margin is smaller, but the perf is faster ( accelerates faster ) above 60mph.

    If the two cars were side by side going 60mph and put the hammer down, the perf car would probably be about 40 feet ahead after another 1000 feet. That's enough to be looking at taillights.
     
  7. ckessel

    ckessel Active Member

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    #7 ckessel, Jul 15, 2012
    Last edited: Jul 15, 2012
    I know, I was trying to get a correlation though which is why I was wondering if my reasoning held up.

    Edit: bleah, removing my extra thoughts, math is hard (and I like math).
     
  8. richkae

    richkae VIN587

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    I made a spreadsheet and some formulas that are consistent with the perf model hitting 60mph in 4.4 seconds and 1/4 mile at 12.6 seconds, and the regular model hitting 0-60 in 5.6 seconds and the 1/4 mile at 13.7 seconds.
    The formulas are oversimplifications and probably do not reflect reality but they are consistent with the 4 data points.
    ( and shows that those 4 data points are not enough to create an accurate model )
    A real time slip with 60 foot time, 1/8 mile time & speed, and 1/4 mile speed would yield a lot more data points and the ability to make an accurate model.

    It yields a 0-100 time for the perf model of 9.8 seconds ( so 60-100 time is 5.4 seconds )
    and a 0-100 time for the standard model of 12.9 seconds ( so 60-100 time is 7.3 seconds )

    If that was the actual performance, I don't think anyone would characterize the perf model as not having a significant advantage over the standard model above 60mph.
     
  9. mcornwell

    mcornwell Active Member

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  10. brianman

    brianman Burrito Founder

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    Since we have some gearheads (or math geeks, or both) on the thread...

    Can a SWAG at "perfect traction" be estimated and combined with the published Peak Motor Power and Peak Motor Torque information to calculate the curve that includes the 0-60 and the quarter-mile? Or are there other missing variables? Can SWAG be applied based on ballpark sea-level, average wind conditions, and the known Cd of the vehicle?

    I would assume the published "0 to 60 mph" and "Quarter Mile Time" must be "worse" than that projection.
     
  11. J in MN

    J in MN S60 P12635

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    Interesting note: While an ICE car performs better at sea level (more oxygen to burn the fuel), an EV performs better at high altitude (less aerodynamic drag).
     

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