Brofessional

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As much as I appreciate the "traction" this is getting, the dude obviously doesn't know what he's talking about with field weakening being the reason torque falls off.

HP = (torque x RPM)/5252

So if you keep power constant (which just happens to be doable in an electric motor in part because of field weakening) what the F does does this clown THINK is going to happen to torque as RPMs increase? The thing could run on GD unicorn farts and it would see the exact same linear reduction in torque as RPMs increased provided power was held constant.

Not only that, but MANUFACTURERS LITERALLY GIVE YOU THE CONSTANT POWER NUMBER. So we can mathematically calculate exactly what the torque will be at any given RPM, and we can also incorporate vehicle weight, drive ratios, and tire diameter to calculate--and I cannot stress this enough--WHAT THE ACCELERATION SHOULD BE AT ANY GIVEN RPM.

However, there are limitations as to the range of rpms over which weakening can be used to keep back EMF at its limit and thus provide constant power, so eventually power starts to fall off. THAT is where you start to get separation of EVs as they don't adhere to simple equations any longer, and it is currently where we find ourselves with the mach e's performance vs the competition.

All these posts/articles/journalists talking about flux and how "torque just falls off" and "needs an induction motor" or a "2nd gear" or whatever other shit spills out of their brains. JFC the education system in this country sucks.

I'm gonna sit down now.
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harrysiii

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I started compiling all of the 60 and 1/4 runs into an Excel spreadsheet (I don't think this has been done yet?) and that 0-60 of yours is actually slower in real time than all of 0t60-3.5's runs but "faster" than all of his runs with the extra rollout.

I've got times so far for you, me, Tommy303, and 0t60, who am I forgetting?
Also, where are you putting your dragy? I've been holding it (will stick the mount on before tomorrow) on my window sill with one finger while I run. On the dash is seems to get no or low GPS, much like my radar detector low on the windshield.
 

harrysiii

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No, the car shuts off all power to the motors while brake holding just FYI.
I'm not sure about that....I feel the car wanting to launch forward and if I'm not pressing the brake hard, the car will move.
 

harrysiii

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mtxpert

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I'm not sure about that....I feel the car wanting to launch forward and if I'm not pressing the brake hard, the car will move.
I hold the brake hard and then floor it, the motors turn off after 1/4 second or so. Maybe be Premium to GT difference.
 

harrysiii

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I hold the brake hard and then floor it, the motors turn off after 1/4 second or so. Maybe be Premium to GT difference.
I'll do some testing. I was thinking about that and hinted in a previous post. I am wondering if a half-throttle hold while brake holding will actually be better than a full throttle hold for just that reason. Or maybe time the throttle press to JUST before releasing the brake....close to simultaneous.
 

Progress

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As much as I appreciate the "traction" this is getting, the dude obviously doesn't know what he's talking about with field weakening being the reason torque falls off.

HP = (torque x RPM)/5252

So if you keep power constant (which just happens to be doable in an electric motor in part because of field weakening) what the F does does this clown THINK is going to happen to torque as RPMs increase? The thing could run on GD unicorn farts and it would see the exact same linear reduction in torque as RPMs increased provided power was held constant.

Not only that, but MANUFACTURERS LITERALLY GIVE YOU THE CONSTANT POWER NUMBER. So we can mathematically calculate exactly what the torque will be at any given RPM, and we can also incorporate vehicle weight, drive ratios, and tire diameter to calculate--and I cannot stress this enough--WHAT THE ACCELERATION SHOULD BE AT ANY GIVEN RPM.

However, there are limitations as to the range of rpms over which weakening can be used to keep back EMF at its limit and thus provide constant power, so eventually power starts to fall off. THAT is where you start to get separation of EVs as they don't adhere to simple equations any longer, and it is currently where we find ourselves with the mach e's performance vs the competition.

All these posts/articles/journalists talking about flux and how "torque just falls off" and "needs an induction motor" or a "2nd gear" or whatever other shit spills out of their brains. JFC the education system in this country sucks.

I'm gonna sit down now.
Do you have enough information about the MME GT to calculate the theoretical acceleration of the car up to 1/4 mile, and what the splits theoretically could be? If so, can you tell if the software is dampening the acceleration at a certain point or if the observed times are the theoretical maximum? Or do other things come into play at high RPMs that make it too difficult to calculate?
 

Mach E JT

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I'll do some testing. I was thinking about that and hinted in a previous post. I am wondering if a half-throttle hold while brake holding will actually be better than a full throttle hold for just that reason. Or maybe time the throttle press to JUST before releasing the brake....close to simultaneous.
I'd wager, just like an ICE vehicle, the TC nannies are getting in the way. You never launch from WOT. You launch from something in the mid range, depending on the road conditions/track prep. So yeah, brake hold and half throttle is probably a way better launch than brake hold and WOT.
 

Pushrods&Capacitors

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Also, where are you putting your dragy? I've been holding it (will stick the mount on before tomorrow) on my window sill with one finger while I run. On the dash is seems to get no or low GPS, much like my radar detector low on the windshield.
Just use the little thin magnetic mount with 3M sticky backing they give you and put that in the cup holder or wherever is flat. LMAO at “holding it….with one finger…”.
 

harrysiii

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Just use the little thin magnetic mount with 3M sticky backing they give you and put that in the cup holder or wherever is flat. LMAO at “holding it….with one finger…”.
Is it really getting enough GPS reception down in the cup holder? Mine is almost always saying "low GPS" if I don't hold it near a side window. :-(

"holding it with my finger." I know!! haha I swear it's not moving! But I'll stick it on prior to tomorrow's runs.
 

Pushrods&Capacitors

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I'll do some testing. I was thinking about that and hinted in a previous post. I am wondering if a half-throttle hold while brake holding will actually be better than a full throttle hold for just that reason. Or maybe time the throttle press to JUST before releasing the brake....close to simultaneous.
What you’re describing is what many auto trans ICE drivers do at the track, it’s called flashing the convertor. Rather than loading it up and causing heat build up you hold the brake firmly and then quickly stab the throttle while simultaneously releasing the brake. This allows the RPM to “flash” to the highest stall speed the convertor is capable of (mine is 1600-1800rpm).
This is the exact method I used on the best runs of the 4X I tested that ran 4.8-5.0 to 60. The 5.0 runs were just matting the throttle with no brake holding.
 

Pushrods&Capacitors

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Is it really getting enough GPS reception down in the cup holder? Mine is almost always saying "low GPS" if I don't hold it near a side window. :-(

"holding it with my finger." I know!! haha I swear it's not moving! But I'll stick it on prior to tomorrow's runs.
Well, I’m in my SS so idk, but when I used it in the 4X I didn’t get the “Low Sats”warning in that location. Or just put it in the giant rubber charging pad area ??‍♂
 

harrysiii

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Who is the user in the non-GT with the trap around 103-104? I can't find it and want to enter that data! :) can anyone link me, please?
 

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I'd wager, just like an ICE vehicle, the TC nannies are getting in the way. You never launch from WOT. You launch from something in the mid range, depending on the road conditions/track prep. So yeah, brake hold and half throttle is probably a way better launch than brake hold and WOT.
However unlike an ICE vehicle electric motors have very rapid and precise response to traction control so I doubt anyone is going to get a way better launch at half throttle. Getting good times in a Y just requires mashing the throttle from everything I’ve read.
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