Dragy times for Plaid and LR

[TorqueMonster]

when talking batteries, here is a good reference that describes key specifications. always good to use industry standard definitions if possible.

http://web.mit.edu/evt/summary_battery_specifications.pdf

 

[mxxg]

Let me poke around some more and see what else I can find

If one assumes (which one probably shouldn't) that the roadster will use 4 of the same motors as the PLAID (same power curve) but with transmission ratios of 6.667:1 instead of 7.5:1 (front and rear), a peak of 1200 hp (new battery?), a maximum of 20,000 rpm and the same tires capable of 1.3 g acceleration, the following can be calculated:

Maximum speed = 250 mph
0-60 in 1.90 sec
0-100 in 3.59 sec (the 4.2 sec quoted above is not reasonable)
1/8 mile in 5.72 sec at 129.4 mph trap speed
1/4 mile in 8.78 sec at 159.5 mph trap speed

No need to uncork anything. Just 4 motors, different gearing and better battery.

Note: I assumed the same car/driver weight since car smaller and should weight less but larger battery weights more.

 

[EndlessPlaid]

If one assumes (which one probably shouldn't) that the roadster will use 4 of the same motors as the PLAID (same power curve) but with transmission ratios of 6.667:1 instead of 7.5:1 (front and rear), a peak of 1200 hp (new battery?), a maximum of 20,000 rpm and the same tires capable of 1.3 g acceleration, the following can be calculated:

Maximum speed = 250 mph
0-60 in 1.90 sec
0-100 in 3.59 sec (the 4.2 sec quoted above is not reasonable)
1/8 mile in 5.72 sec at 129.4 mph trap speed
1/4 mile in 8.78 sec at 159.5 mph trap speed

No need to uncork anything. Just 4 motors, different gearing and better battery.

Note: I assumed the same car/driver weight since car smaller and should weight less but larger battery weights more.

Unfortunately, it's unlikely that the Roadster will get quad motors. However, it's likely that the Roadster will be approaching, if not exceeding 1,300 hp with motor improvements discussed in this tweet. Also, the top speed should also be above 250 mph, with the increased rpm.

https://twitter.com/x/status/1404130459924135944

 

[mxxg]

Unfortunately, it's unlikely that the Roadster will get quad motors. However, it's likely that the Roadster will be approaching, if not exceeding 1,300 hp with motor improvements discussed in this tweet. Also, the top speed should also be above 250 mph, with the increased rpm.

https://twitter.com/x/status/1404130459924135944

Could be. I picked the 6.667:1 gear ratio because it gives 250 mph at 20,000 rpm with the 28” diameter tires which are on the refresh MS. The 250 mph and 20,000 rpm both came from Tesla. I used 4 motors because they exactly match the performance times quoted without any changes in the motors. However, knowing Tesla, this is to simple. LOL

 

[EndlessPlaid]

Could be. I picked the 6.667:1 gear ratio because it gives 250 mph at 20,000 rpm with the 28” diameter tires which are on the refresh MS. The 250 mph and 20,000 rpm both came from Tesla. I used 4 motors because they exactly match the performance times quoted without any changes in the motors. However, knowing Tesla, this is to simple. LOL

I love your calculations. Especially the performance guesses. I'm thinking maybe a bit faster 0-60 on a dragstrip (maybe 1.84 to beat the Rimac.) Excellent reduction gear ratio guess though. I suspect that is quite accurate.

 

[mxxg]

I love your calculations. Especially the performance guesses. I'm thinking maybe a bit faster 0-60 on a dragstrip (maybe 1.84 to beat the Rimac.) Excellent reduction gear ratio guess though. I suspect that is quite accurate.

0-60 time is a function of tires ONLY at this HP. Slightly better tires will give slightly better times. Also, another reason I think the roadster will have 4 motors is that it will almost impossible to find tires that will handle twice as much power to the rear wheels like the PLAID has. To get much better than PLAID times, you need much more balanced power front/rear.

 

[EndlessPlaid]

0-60 time is a function of tires ONLY at this HP. Slightly better tires will give slightly better times. Also, another reason I think the roadster will have 4 motors is that it will almost impossible to find tires that will handle twice as much power to the rear wheels like the PLAID has. To get much better than PLAID times, you need much more balanced power front/rear.

The tires are always the issue for sure. I think with Cup2s on a dragstrip, sub 1.90 is potentially doable. The power split problem is interesting, but Elon has stated multiple times over the years that the Tri-Motor powertrain would be in the Roadster, and that tri-motor development was an important precursor to the Roadster. Maybe a shorter final drive would help. Like 7:1.

 

[mxxg]

The tires are always the issue for sure. I think with Cup2s on a dragstrip, sub 1.90 is potentially doable. The power split problem is interesting, but Elon has stated multiple times over the years that the Tri-Motor powertrain would be in the Roadster, and that tri-motor development was an important precursor to the Roadster. Maybe a shorter final drive would help. Like 7:1.

The problem of having different gearing on the front and rear is that at 250 mph top speed, one of the motors will be over 20,000 rpm.

 

[EndlessPlaid]

The problem of having different gearing on the front and rear is that at 250 mph top speed, one of the motors will be over 20,000 rpm.

Exactly. I actually meant bumping both axles to 7:1. I think one ratio for both is the way to go. Now, if they manage to get like 23,000 rpm out of these motors, I'm thinking that would help the top speed issue.

 

[TwoK4drSi]

The Roadster will use the 4680s and the structural pack, and so would've the Plaid Plus. Not the 18650s. It makes no sense to bake this much power into a battery that would never be used for the Roadster. Additionally, the battery's potential is almost always shown in the form of potential motor power than can be made. Think the Plaid's current 1,020 hp to the 1,200 hp potential.

That’s only the assumption they would use the same battery size. The roadster at glance looks shorter therefore it’s not a fair apples to apples comparison

 

[EndlessPlaid]

That’s only the assumption they would use the same battery size. The roadster at glance looks shorter therefore it’s not a fair apples to apples comparison

 

[LargeHamCollider]

Guys, I hate to steal your thunder, or rain on the parade, but there is no way in Hell that the battery is making 1400hp or something crazy like that.
Put it this way: A lot of people are commenting that the Plaid is accelerating like a 1100hp or 1200hp car. It is. But keep in mind that that it's putting down to the wheels what a 1200 hp ICE would be. Additionally no car like this has ever existed before, where it can hold max power and torque throughout the entire 1/4 mile, with the efficiencies of an EV, so the traditional calculations for 1/4 mile and trap speed to hp will almost certainly be inaccurate.

Just the heat generated alone by this power loss would be insane. This would make this EV substantially LESS efficient than an ICE. Like really bad.

I am strongly leaning towards an equipment error here guys.

Eh, this is some pretty poor pontification.

It's possible that the plots Omar has shown are wrong, but that's very unlikely.

If they are right then 100% the battery is making 1400hp, it's right there in the plots.

This would NOT show the EV is substantially less efficient than ICE, this would show the plaid being 1020/1400 =73% efficient, far more efficient than any ICE. But also far less efficient than the 90% plus that Tesla motors get in normal circumstances. 73% is probably about right for the extreme end of the performance curve (though I would have guessed somewhat higher).

ICE engines are about 35% efficient so a 200hp ICE engine at max power would generate about the same heat as a Plaid at max power, nothing too extreme there.

 

[EndlessPlaid]

Eh, this is some pretty poor pontification.

It's possible that the plots Omar has shown are wrong, but that's very unlikely.

If they are right then 100% the battery is making 1400hp, it's right there in the plots.

This would NOT show the EV is substantially less efficient than ICE, this would show the plaid being 1020/1400 =73% efficient, far more efficient than any ICE. But also far less efficient than the 90% plus that Tesla motors get in normal circumstances. 73% is probably about right for the extreme end of the performance curve (though I would have guessed somewhat higher).

ICE engines are about 35% efficient so a 200hp ICE engine at max power would generate about the same heat as a Plaid at max power, nothing too extreme there.

I would read this. This person is an engineer who works with Insideevs, and he just wrote up a great summary. Really helped me out:

Model S Plaid Battery Details, sourced from EPA Docs, Vehicle Observations, & Supercharging/Charging data

COMPLETELY AGREE it's well documented that the loss with EVs are very very low Additionally, no one (especially Tesla) rate their cars at the wheel. They always take the bigger number for marketing.

teslamotorsclub.com

 

[LargeHamCollider]

I would read this. This person is an engineer who works with Insideevs, and he just wrote up a great summary. Really helped me out:

Model S Plaid Battery Details, sourced from EPA Docs, Vehicle Observations, & Supercharging/Charging data

COMPLETELY AGREE it's well documented that the loss with EVs are very very low Additionally, no one (especially Tesla) rate their cars at the wheel. They always take the bigger number for marketing.

teslamotorsclub.com

Not a bad post from Ritter. For what it's worth I'm also an engineer, Aerospace not automotive, but I did design the battery pack for a land speed record electric car.

Note that Ritter's post is speculation and that EPA docs (at least ones involving motor power) are notoriously inaccurate. Also Ritter's understanding of EV motor efficiency vs torque and rpm levels appears to be deficient. EV Electric pm motors never maintain peak efficiency in the max torque condition. 96%+ efficiency at max torque is completely unrealistic for this sort of motor. I've attached a torque/rpm/efficiency plot for reference (this plot is just from Google and looks like others I've seen, I've no personal experience with this motor).

 

[SignatureSales]

We are proud to announce that Brooks from Dragtimes and the record holder Eric have placed orders for a set of signature wheels for their plaid model S. We are super excited to see the results as they are both gunning for the 8.XX mark. Stay tuned and watch for them as we are sure they’ll post their results on their YT channel.

If you are interested in a set let us know as we have partnered with a TUV certified company for titanium lug nuts which will be discounted with an order.

We only offer the strongest wheels and lug nuts for your 1020 hp rocket ship when you’re gunning down the race track or standing still. Since we are the official wheel of the Ford Performance Racing School with zero failures to date we are confident that the wheel you order / lug nuts will meet your speed needs”
Two weeks away from a set of Track Spec SV104 being complete for Brook from Dragtime. Look forward to be the fastest 1/4 miles Plaid with full interior.

DM me if you have any questions regarding tire and fitment options as we are the first wheel company to carefully measure every suspension and interference component on both the model S Plaid and Long Range at all suspension height settings​

 

[TorqueMonster]

We are proud to announce that Brooks from Dragtimes and the record holder Eric have placed orders for a set of signature wheels for their plaid model S. We are super excited to see the results as they are both gunning for the 8.XX mark. Stay tuned and watch for them as we are sure they’ll post their results on their YT channel.

If you are interested in a set let us know as we have partnered with a TUV certified company for titanium lug nuts which will be discounted with an order.

We only offer the strongest wheels and lug nuts for your 1020 hp rocket ship when you’re gunning down the race track or standing still. Since we are the official wheel of the Ford Performance Racing School with zero failures to date we are confident that the wheel you order / lug nuts will meet your speed needs”
Two weeks away from a set of Track Spec SV104 being complete for Brook from Dragtime. Look forward to be the fastest 1/4 miles Plaid with full interior.

DM me if you have any questions regarding tire and fitment options as we are the first wheel company to carefully measure every suspension and interference component on both the model S Plaid and Long Range at all suspension height settings​

How much lighter are these wheels compared to stock?

 

[TorqueMonster]

If one assumes (which one probably shouldn't) that the roadster will use 4 of the same motors as the PLAID (same power curve) but with transmission ratios of 6.667:1 instead of 7.5:1 (front and rear), a peak of 1200 hp (new battery?), a maximum of 20,000 rpm and the same tires capable of 1.3 g acceleration, the following can be calculated:

Maximum speed = 250 mph
0-60 in 1.90 sec
0-100 in 3.59 sec (the 4.2 sec quoted above is not reasonable)
1/8 mile in 5.72 sec at 129.4 mph trap speed
1/4 mile in 8.78 sec at 159.5 mph trap speed

No need to uncork anything. Just 4 motors, different gearing and better battery.

Note: I assumed the same car/driver weight since car smaller and should weight less but larger battery weights more.

I think the 1/4 trap speed of the roadster will be in the 160s. The Plaid is already 152+ and likely will be trapping at 155 mph when all said and done. Not much of a difference between 155 and 159 mph trap speeds. At a minimum I would hope for a 10 mph difference.

 

[TorqueMonster]

Let me poke around some more and see what else I can find

@omarsultan any new updates to this? I must admit I am baffled by the 1400 HP battery power reading. Keith indicated (if i read his post correctly) a 1097 HP number at the battery.

 

[EndlessPlaid]

@omarsultan any new updates to this? I must admit I am baffled by the 1400 HP battery power reading. Keith indicated (if i read his post correctly) a 1097 HP number at the battery.

Yes please @omarsultan! His calculations also came out to 993 hp at the wheels. Would love to hear some news on this.

 

[omarsultan]

Yes please @omarsultan! His calculations also came out to 993 hp at the wheels. Would love to hear some news on this.

Working on it--been going through the DBC to find messages and signals that are interesting. It seems a lot of signals for the rear motors have not been mapped yet.