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Regen compared to driving manual transmission ICE.

Discussion in 'Model S: Driving Dynamics' started by Fiver, May 2, 2015.

  1. Fiver

    Fiver Member

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    I'm one of the few left in the US who drives a manual transmission car. I've always preferred it over automatic. Regen is noted frequently in these forums as something drivers need to get used to when transitioning to the MS. As someone who drives a stick and constantly is downshifting when approaching stops to save my brake pads, is it basically the same thing? Obviously there is no downshift in a Tesla, but the act of pacing your vehicle so it slows down using the gears vs using your brakes to stop at each light?
     
  2. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    I've mostly driven manuals as well, and yes, it's basically the same thing. Note that Tesla delivers the car with "creep on". First thing to do is turn creep off.
     
  3. SomeJoe7777

    SomeJoe7777 Marginally-Known Member

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    Until my previous vehicle (bought in 2011), I drove manual transmission vehicles ever since I got my license in 1985. Yes, there is a definite parallel between using engine-braking in a manual transmission vehicle and regen in the Tesla. Letting off the gas in the manual transmission ICE slows the vehicle down much as regen does in the Tesla, but it's more work because downshifting is required to maintain the engine-braking.

    It took me all of 2 days of driving with the Tesla regen for it to become second nature. I can now easily drive on surface streets basically without using the brakes at all except for the final 5 MPH at stop lights.
     
  4. Candleflame

    Candleflame Member

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    I would avoid downshifting to save brake pads (unless you a rolling down a hill) as the transmission and clutch is more expensive to maintain these days than brakes. I think you can even get a minor fault in the eco safe driving section during a driving test these days with it. Brakes make you stop, gears make you go or something like that. :p
     
  5. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    But the gears and engine are designed for many tens of thousands of miles (hopefully) but it's easy to wear out a set of brakes in 30K miles (thanks VW) even with doing most stopping using the gears. There is no difference to the gears in going forwards or backwards. I've done it with all my manual cars and I have yet to wear out a transmission or engine from that practice.
     
  6. vvanders

    vvanders Member

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    Properly done double-clutched downshift is totally fine, and preferred if you can manage it. There's a reason you always see signs on steep mountain passes that say to use engine braking.

    I went 140k on the original clutch on my last car. Probably had another 20k miles before it needed to be replaced.
     
  7. Candleflame

    Candleflame Member

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    #7 Candleflame, May 2, 2015
    Last edited: May 2, 2015

    I always assumed you need to double clutch when downshifting to be kind to the synchronizers, however, I find if I just depress the clutch pedal then shift and then apply some gas once and then release the clutchpedal it seems to paradoxically have the same effect of a smooth gear change as double clutching. Even if I downshift from like 4000 rpm to a lower gear and end up at 1500 rpm or so. Any thoughts on this?
     
  8. Fiver

    Fiver Member

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    I think outside of large trucks double clutch isn't needed as pretty much every single modern car has a synchronized manual transmission.

    /edit every single modern manual transmission car*
     
  9. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    I like to think of driving a Tesla in normal regen is a lot like driving a standard transmission sports car always in 1st or 2nd gear; there is no down shifting because you do not shift, but the gearing is like 1st or 2nd on most standard transmission sports cars. The big difference is that the top end is 155 mph in the MS instead of the 40-70 mph you would get in a standard in 1st or 2nd.
     
  10. Dwdnjck

    Dwdnjck Member

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    Regent seems to be adjustable by how much pressure you put on the accelerator pedal. On a hill near my home, full regen will stop the car going downhill. However, you can vary the speed going downhill with your foot without going from green to orange.
     
  11. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    That's correct. It's basically acceleration in reverse, and you can control it very precisely.
     
  12. vvanders

    vvanders Member

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    It's true that it matches up the synchros, however it also has the net-effect of spinning up the driveshaft, flywheel and pistons as well.

    When you downshift without double-clutching your clutch catches a bit to bring those intermediate parts up to speed and that's where a bit of extra wear can come from. If you're really good(and like risking your transmission) you only need to clutch in once to neutral, a *perfect* rev-match will actually go into gear without any clutch work. That said unless you get it just right there's a high chance of grinding off the gear edges so it's safer to just clutch a second time.

    Thankfully an EV simplifies all of this, although it's nice to know for posterity's sake.
     
  13. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    Never seemed to bother my Series III Land-Rover any (though I only drove it for twenty years) and although I have a lot of bad things to say about the VW TDI, gear wear on the manual transmission wasn't one of them.
     

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