Sandy Munro talks about the teardown of the Model 3

[JeffK]

Ok then ….list what you can remove from the Model 3 and it still be a Model 3.

You can replace all the body panels with painted composite. For pure track use it'd be a great performer.

 

[EinSV]

Yes, I watched the whole video. I'm not debating if the Model 3 is a great handling car, I purchased my Performance 3 over a BMW M2 Competition or BMW M3. It IS a great handling car, but the question I was answering is why weight is important (with one article to start that can explain to the non traditional car enthusiast why 0-60 and power is only part of the story). I'm not going to answer past that because this is such a widely known fact that Garlan can simply choose to educate himself if he wishes.

The Model 3 accelerates fast and handles well despite its weight. Shave 500lb off the body and it would be insanely good. Untouchable. This is why I'm interested in hearing a rebuttal from Tesla on Munro and his body criticisms.

I agree that all things being equal, lighter is better for handling. I’m sure Tesla gets that but they also have to make sure the car is safe. Some of Munro’s comments about extra weight below the battery betrayed his ignorance about the need to protect the battery from road hazards. As far as his other criticisms I doubt he has any deep knowledge about EV designs but I tend to give more credence to points he made about the standard body parts like the trunk.

Bottom line is that the Model 3 is fantastic out of the box. Tesla is constantly tinkering so I’m sure it will just get better over time. If Sandy’s ideas have validity I’m sure Tesla won’t hesitate to incorporate them.

 

[voip-ninja]

I think Munro missed explaining why it matters that the M3 chassis is overbuilt and too heavy. So what? There’s plenty of power at all speeds thanks to a “magic” motor. Performance efficiency is excellent despite the extra weight. Balance is superb.

So the frame is structurally sound without relying on the battery pack for stiffness. Why does Munro believe this is a bad thing? If a Sherman tank had M3 performance specs, no one would complain. If a car with M3 performance specs can be built like a Sherman tank, I fail to see the design issue. It’s msrketing material.

Munro believes it’s a bad thing because the car could have been built for less expense and had an identical safety rating, in his opinion. That is pretty clear.

If the car weighed less it would also have better range, better handling, etc.

 

[Garlan Garner]

Oh well i don't think those are really that important as you could easily stuff more power (or unlock it via software) into the Model 3 and crush the P100D, but that will be called the Roadster or something like that

The motors on the 3 are different than the S. That's what makes the Model 3 more efficient in range. That's why the Model 3 can travel further than the S.

There is a one permanent magnet and one induction in the performance Model 3. One for power and the other for range. The model 3 performance is stupid quick at 3.1 0-60, however it can't pull the current through the inverter fast enough to get to the 2.3 0-60 of the P100D.

 

[Garlan Garner]

Munro believes it’s a bad thing because the car could have been built for less expense and had an identical safety rating, in his opinion. That is pretty clear.

If the car weighed less it would also have better range, better handling, etc.

Let me ask you....What factors are most important to Tesla concerning their Model 3?

Range?
Handling?
Cost?
Acceleration?
Race Track?
Safety in an accident?
etc?

 

[JeffK]

The motors on the 3 are different than the S. That's what makes the Model 3 more efficient in range. That's why the Model 3 can travel further than the S.

There is a one permanent magnet and one induction in the performance Model 3. One for power and the other for range. The model 3 performance is stupid quick at 3.1 0-60, however it can't pull the current through the inverter fast enough to get to the 2.3 0-60 of the P100D.

Yet there are smaller batteries which can do better because they're set up for speed.
Ford Mustang Electric Drag Car Does 0 To 60 MPH Under 2 Seconds, Targets 200 MPH

I think Tesla could have easily bested the P100D with the Model 3 if they had wanted to.

 

[voip-ninja]

Ok then ….list what you can remove from the Model 3 and it still be a Model 3.

LOL. No. Not getting into a discussion like that with a guy who goes into pedantic rants where all that matters is 0-60 and 1/4 times regardless of how heavy or efficient a vehicle is.

Munro already stated in detail what could have been done differently in M3 body design and construction to reduce weight and manufacturing cost with zero impact to safety.

Per Munro, Elon cut him off about unibody design criticism with the comment “I fired that guy”.

 

[Garlan Garner]

You can replace all the body panels with painted composite. For pure track use it'd be a great performer.

But there would an increase in price. Wouldn't there?

 

[JeffK]

But there would an increase in price. Wouldn't there?

It depends, over the last few years there have been some recent advances making certain composites cheaper than steel.

 

[Garlan Garner]

Munro already stated in detail what could have been done differently in M3 body design and construction to reduce weight and manufacturing cost with zero impact to safety.

”.

LOL... Morono should have started his own EV company.

Nice evasion of discussion.

 

[Garlan Garner]

LOL. No. Not getting into a discussion like that with a guy who goes into pedantic rants where all that matters is 0-60 and 1/4 times regardless of how heavy or efficient a vehicle is.

Munro already stated in detail what could have been done differently in M3 body design and construction to reduce weight and manufacturing cost with zero impact to safety.

Per Munro, Elon cut him off about unibody design criticism with the comment “I fired that guy”.

You don't seem to understand that even if my car weighted 1 million pounds....if my car can go 0-60 in 1.9 seconds.....who cares what it weighs if its NEVER going on a track?

The Model 3 wasn't developed for the track.


I don't agree with the argument of placing a sedan on the track and criticizing it for not performing like a track car.

Now wait for the roadster 2. Then you can make all of the track criticisms you want.

 

[ricohman]

Ok ricohman. I understand your point. I really do.

However....If an EV reduces weight...it would have a reduction in torque.

If I removed batteries from my car....I won't have the torque. It would be lighter but slower.

I'm not understanding why that's not understood.

This I do not know. Would a smaller pack give the same power output for a shorter time? This is beyond my experience and I won't even make a guess.
It would be something if you could swap a smaller battery for a handful of runs. Imagine a half size battery that weighs 500lbs less. It would be like removing 2 large dudes from your car. But shorter range though.
Speaking of range. If I buy my car in Calgary I don't think I can drive it back to Saskatchewan as we have no charging infrastructure. Or so I have read. And it's over 850km away.

 

[JeffK]

This I do not know. Would a smaller pack give the same power output for a shorter time? This is beyond my experience and I won't even make a guess.
It would be something if you could swap a smaller battery for a handful of runs. Imagine a half size battery that weighs 500lbs less. It would be like removing 2 large dudes from your car. But shorter range though.
Speaking of range. If I buy my car in Calgary I don't think I can drive it back to Saskatchewan as we have no charging infrastructure. Or so I have read. And it's over 850km away.

Depending on the battery chemistry you can certainly pull more power from a smaller pack for less time if it has adequate cooling and can handle the higher C rate.

 

[paranoidroid]

He actually mentioned that without a battery that car is just as safe as with it. I.e. it could be still just as safe with weaker body.

Exactly, this is what I'm interested in hearing about. Munro said Tesla didn't take advantage of the battery when designing the frame and it could be made just as safe as today but with less mass in the frame - thus it's overweight. He claims Tesla should use finite-element analysis - such as OptiStruct by Altair which he mentioned many times. It seems improbable Tesla doesn't already do this and I shared a sample animation from Tesla that is output using such software.

Perhaps it's as simple as that (resoundingly horrible and obvious mistake) was made by a rookie and Elon fired him and we're all stuck with a body that's a couple hundred pounds heavier than it needs to be. But I'd like to hope there is a more nuanced reason. As even Munro says Tesla has some very elite engineers and it's hard to see how something like that could have gotten overlooked.

 

[Garlan Garner]

This I do not know. Would a smaller pack give the same power output for a shorter time? This is beyond my experience and I won't even make a guess.
It would be something if you could swap a smaller battery for a handful of runs. Imagine a half size battery that weighs 500lbs less. It would be like removing 2 large dudes from your car. But shorter range though.
Speaking of range. If I buy my car in Calgary I don't think I can drive it back to Saskatchewan as we have no charging infrastructure. Or so I have read. And it's over 850km away.

Great question. concerning the pack size.

The answer is NO. The Model 3's batteries pull from each cell equally.

That way the motors can get full torque from its entire pack. If you reduce the pack size...you reduce your available Kilowatts.

 

[Garlan Garner]

Depending on the battery chemistry you can certainly pull more power from a smaller pack for less time if it has adequate cooling and can handle the higher C rate.

True, however the Model 3's motors pull from the entire pack at once. If you reduce the number of batteries....you have less available power to the motors.

The only other car that works like the Model 3 is the newer P100D model S.

 

[JeffK]

it could be made just as safe as today but with less mass in the frame

Only if you intend to total the battery, possibly cause a fire in case of an accident.

 

[JeffK]

True, however the Model 3's motors pull from the entire pack at once. If you reduce the number of batteries....you have less available power to the motors.

No, a different chemistry capable of higher C rate can pull just as much power in a much smaller pack. Thus you can reduce the number of cells and keep the power density but lose the energy density.

The life of the battery would be much shorter, but that's not the point. You can make a super quick 1/4 mile car.

 

[Garlan Garner]

Exactly, this is what I'm interested in hearing about. Munro said Tesla didn't take advantage of the battery when designing the frame and it could be made just as safe as today but with less mass in the frame - thus it's overweight. He claims Tesla should use finite-element analysis - such as OptiStruct by Altair which he mentioned many times. It seems improbable Tesla doesn't already do this and I shared a sample animation from Tesla that is output using such software.

Perhaps it's as simple as that (resoundingly horrible and obvious mistake) was made by a rookie and Elon fired him and we're all stuck with a body that's a couple hundred pounds heavier than it needs to be. But I'd like to hope there is a more nuanced reason. As even Munro says Tesla has some very elite engineers and it's hard to see how something like that could have gotten overlooked.

I don't believe ANYTHING was overlooked on the Model 3.

Did you see how long they took to design that car?

 

[Garlan Garner]

No, a different chemistry capable of higher C rate can pull just as much power in a much smaller pack. Thus you can reduce the number of cells and keep the power density but lose the energy density.

The life of the battery would be much shorter, but that's not the point. You can make a super quick 1/4 mile car.

Oh yes...I would agree.

New technology could yield fewer batteries. Of course.

However as it stands today -

I remember Elon talking about playing with the amount of graphite on the cathode to get a better discharge rate out of each cell, however with all of the cobolt that would be required required on the anode - each cells degradation would accelerate entirely too fast and the pack would lose about .09% of its capacity after each 3.1 second launch.