Why Can't The Mach-E GT Do This?

[Regulus7]

So does the 5s clock start when you press the pedal all the way down? What if you pressed like “ 90% “ and held it there. Would the 5s never kick in? Given the 350Kw = 470hp I suppose you could limit to 320Kw at 90% and not be limited ?!?

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[tesla2mme]

This is exactly right.

It is full throttle until you see it drop to below 0 because it starts using regen immediately as you let off the accelerator. Even with 1PD off, as soon as you let off, the power meter shows a very small amount of regen happening, and then it kicks up when you hit the brake pedal.

This is really fascinating science you're doing, we all truly do appreciate this, I assure you !!!! Thank you!

Do you have any plans to do this for roll-on WOT runs? Like say, starting at 35 MPH.

If it is truly a "timed limitation" for 5 seconds of wide open, would that hold true even while you're already moving? I am curious...

How have you assessed that the HVB sensor is accurate and working properly? Just curious. The MME GTPE would be such a perfect car for me if it did not have this ridiculous nanny limit. Such a strong dose of hopium that some day this can be rectified in the aftermarket.

 

[dtbaker61]

I think all these runs ended with me hitting between 95-100mph



I will try that tomorrow. I also want to try a few runs in unbridled extend just to see what those look like.



Just based on what I'm seeing, its looking more and more like its just a timed limitation over an actual sensor based limitation at this point.

the scale on the calculated kw make it really hard to tell what the duration of 'full current' is. It might take a look at the raw data to determine the duration with much accuracy. I'm most interested in the duration of the 'flat top' , down to the 1/10 sec, and then seeing if there is a direct correlation in the time slice power is restricted to the primary inverter temp hitting 'some temp'... or if the restriction is purely 5.0 seconds at 100%.

my hypothesis is that current is restricted at a very specific temp, and held down until temp recovers.... which appears to be pretty fast for the primary inverter temp. This would be great news for the Draggies out there because chilling the coolant line to the inverter could have a much quicker response to greater heat transfer because of the smaller mass compared to the batteries.

This could be verified if there is a difference in time at 100% when starting from rest after inverter temp has 'recovered', versus quick runs before temp recovers. i.e.

- make first run from 'cold' and hold 100% until restriction kicks in, this should capture the full power duration we expect of 5 sec or thereabouts. Turn around and get back to your start....

- second run, 100% for 5+ sec till power cuts, accell 0% for 5 sec in 1-p mode to keep the inverter working hard with the regen so it doesn't cool down all the way, then hit it again 100% throttle. If temp is the key, the second acceleration will be something less than 5 seconds since the inverter was not allowed to cool after the first acceleration.

You may get better resolution from higher sample rate if you capture ONLY kW and inverter temp. The idea is to find the time slice that power is reduced, and determine whether it is at a specific inverter temp, or a specific time at 100%

 

[dtbaker61]

So does the 5s clock start when you press the pedal all the way down? What if you pressed like “ 90% “ and held it there. Would the 5s never kick in? Given the 350Kw = 470hp I suppose you could limit to 320Kw at 90% and not be limited ?!?

hence my bet it is temp and not time

 

[benk016]

Do you have any plans to do this for roll-on WOT runs? Like say, starting at 35 MPH.

Todays runs, the 4th one, started at 40mph, and seems to react the exact same way as the rest starting from stopped.

How have you assessed that the HVB sensor is accurate and working properly? Just curious. The MME GTPE would be such a perfect car for me if it did not have this ridiculous nanny limit. Such a strong dose of hopium that some day this can be rectified in the aftermarket.

The sensor is accurate. The temps rise pretty quick when DC Fast Charging. It'll go from mid 60's to high 90's during a Fast Charge.

The only unknown is where in the pack this temp is read from. It could just be ambient temps inside of the pack, and not a temp that the cells are at. But I would suspect if the individual cells are getting hot it would warm up the whole pack like DC Fast Charging does.

Given the 350Kw = 470hp

Interestingly the first run today, you can see that little blip at the top of the first run, it registered 376.775kW. None of the others have went that high.

 

[0t60-3.5]

Ben, can you track throttle position?

Alternately, if its as simple as you are at 100% throttle until the sharp drop with kW goes to zero, that answers my question.

Interestingly, 350kW = 470hp.......

Funny, way back in August when I was the first to take a GT PE to the drag strip, that question arose as well... people were inferring that I had let up on the throttle. Nope... I had it floored all way through the trap and afraid I was pushing too hard!

My GT Performance Edition (GTPE) first track launch with videos, timeslip! 0-60 in 4.12s, 1/4 mile in 12.657 @ 100.02 mph

I definitely got the feeling after 80mph / 5 seconds of "come on, you got more than this, keep going... !!!!" The initial 5 seconds of thrust / acceleration is fantastic but definitely has a slow down. We didn't know at the time of the 5 second limitation.

 

[benk016]

the scale on the calculated kw make it really hard to tell what the duration of 'full current' is. It might take a look at the raw data to determine the duration with much accuracy. I'm most interested in the duration of the 'flat top' , down to the 1/10 sec, and then seeing if there is a direct correlation in the time slice power is restricted to the primary inverter temp hitting 'some temp'... or if the restriction is purely 5.0 seconds at 100%.

my hypothesis is that current is restricted at a very specific temp, and held down until temp recovers.... which appears to be pretty fast for the primary inverter temp. This would be great news for the Draggies out there because chilling the coolant line to the inverter could have a much quicker response to greater heat transfer because of the smaller mass compared to the batteries.

This could be verified if there is a difference in time at 100% when starting from rest after inverter temp has 'recovered', versus quick runs before temp recovers. i.e.

- make first run from 'cold' and hold 100% until restriction kicks in, this should capture the full power duration we expect of 5 sec or thereabouts. Turn around and get back to your start....

- second run, 100% for 5+ sec till power cuts, accell 0% for 5 sec in 1-p mode to keep the inverter working hard with the regen so it doesn't cool down all the way, then hit it again 100% throttle. If temp is the key, the second acceleration will be something less than 5 seconds since the inverter was not allowed to cool after the first acceleration.

You may get better resolution from higher sample rate if you capture ONLY kW and inverter temp. The idea is to find the time slice that power is reduced, and determine whether it is at a specific inverter temp, or a specific time at 100%

I attached the full output of todays runs.

Most of my runs are from stopped, full throttle to 95 mph, then hard regen back down to around 40mph. And then not doing another run again until the power meter limitation goes away.

The first 4 runs the limitation goes away pretty quick. Usually within 10 seconds of getting back to normal speed. But the last few it was taking a bit longer. 30 seconds or so.

 

[dtbaker61]

Also 1 request: please try easing into the throttle instead of stabbing it. I’m curious if the inverter temp won’t spike that way and if the drop in power is less severe. My car feels faster easing into it vs stabbing for some reason.

if the inverter cooling is designed for 'steady state' cooling at the <50kw it takes to roll along at highway speed.... then my guess is that the time you have at higher output is tied directly to how much over 50kw you are asking for and how much time the inverter has had to cool.

so yeah, at 90% throttle, the duration will likely be longer until the inverter hits some specific temp and restricts current.

 

[dtbaker61]

Funny, way back in August when I was the first to take a GT PE to the drag strip, that question arose as well... people were inferring that I had let up on the throttle. Nope... I had it floored all way through the trap and afraid I was pushing too hard!

I definitely got the feeling after 80mph / 5 seconds of "come on, you got more than this, keep going... !!!!" The initial 5 seconds of thrust / acceleration is fantastic but definitely has a slow down. We didn't know at the time of the 5 second limitation.

you look like a guy ready to be the first to break the 5 second barrier..... Do you have any interest in a plumbing mod to run the inverter coolent inlet thru an ice bath/heat exchanger? my bet is that lowering the inlet temp from 70 deg to 40 deg would buy you another second or two at full throttle.

 

[Electric Goat]

@benk016 thanks for putting in the work for all of this data.

Based on this new data, I don't see any reason whatsoever as why there is a 5 second limit in place.

Also, based on the acceleration modeling in the thread linked below, the base Mach-E GT should at least hit the 1/4 mile doing 12.0 @ 116 mph.

https://www.macheforum.com/site/thr...ssible-performance-capability-of-the-gt.9599/

 

[dtbaker61]

I attached the full output of todays runs.

Most of my runs are from stopped, full throttle to 95 mph, then hard regen back down to around 40mph. And then not doing another run again until the power meter limitation goes away.

The first 4 runs the limitation goes away pretty quick. Usually within 10 seconds of getting back to normal speed. But the last few it was taking a bit longer. 30 seconds or so.

what we are after is doing another run right away to establish the tie to temp.

My bet is that the gray bars are tied to inverter temp (or a combination of inverter/motor/battery temps).... and that strongly affects the duration of 'full power'. If you are waiting for Inverter temp to recover before another run, it is predictably giving the same 5 seconds because that's the time it takes to heat back up to the temp that clamps down on current.

you have shown us all that the most reactive temp is the primary inverter, although the steady climb of the motor coils under repeat runs plays in later runs most likely. Unless there is another battery cell temp sensor that we haven't found....

 

[Mach1E]

So does the 5s clock start when you press the pedal all the way down? What if you pressed like “ 90% “ and held it there. Would the 5s never kick in? Given the 350Kw = 470hp I suppose you could limit to 320Kw at 90% and not be limited ?!?

I would be shocked if you could trick the limit by not going full throttle, but it’s worth a shot.

Usually things like this would be programmed by tables that are all adjusted based on the inputs (like speed, temp, throttle position etc).

If you could somehow go faster by going slower (like 90% throttle) it’s worth a shot.

Of course actually getting it to and keeping it at 90% would be difficult.

I can see it now. The aftermarket solution to the 5 second limit:
https://www.amazon.com/block-wood/s?k=block+of+wood

 

[Cabel]

Who cares? It's a crossover family SUV with a sh1t-ton of style and performance. Really, on a day-to-day basis, do you need to launch to 116mph with the kids in the back seat? The most that I see ever needing is 2-3 seconds needed to get in front of that semi barreling down on me as I merge onto the highway.

 

[Mach1E]

Who cares? It's a crossover family SUV with a sh1t-ton of style and performance. Really, on a day-to-day basis, do you need to launch to 116mph with the kids in the back seat? The most that I see ever needing is 2-3 seconds needed to get in front of that semi barreling down on me as I merge onto the highway.

Need?

 

[Cptmorgemaker]

exactly

I keep waiting for one of the 5 second complainers to try a mod to flash-cool the battery/inverter/motor coolant loop and report results. Could be as simple as rigging a fire extinguisher in front of the radiator and bleeding some CO2 thru it prior/during a drag run.

If that buys more than 5 seconds at 100% current, and more 'long term' mod could be to pull the frunk and add an electric chiller (heat pump) and inline heat exchanger to chill the coolant loop.

Just get like 4 tanks in parallel give u more time. ?

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