[2cycle]

I picked up a car magazine this weekend because it had done a multi day test session with the Tesla. The guy really liked it for stoplight to stoplight fun. He mentions the lack of top speed but also reminds us that top speed is rarely used and was worth the trade off of the off the line punch.
They showed some interesting numbers that were either chassis dyno figures or onboard dyno figures. It pretty much shows what I thought all along, it has great off the line torque to the rear wheels but as soon as it gets past 40 mph it's all gone and heading down hill quick. They showed a comparison to the V-6 Camaro and as soon as the Camaro shifts to second gear the torque to the wheels as already more than the Tesla is at that point during a sprint. When you campare the weight specs you will see that the Tesla is more than 1000 lbs lighter, that's where the performance comes from. After reading that write-up I would have to say a 2 or 3 speed tranny would surely make the torque to the rear wheels show better but the weight would slow it down off the line to gain the top speed and it wouldn't be worth it.

[2cycle]

After reading the article some more it does mention about going to their web site to see the dyno tests, so it sounds like they used a chassis dyno to measure rear wheel hp. I think it was something like 1200 lb/ft to the rear wheels from start to around 40 mph then it starts a linear drop to the peak speed.

[Bowser330]

Originally Posted by 2cycle

I picked up a car magazine this weekend because it had done a multi day test session with the Tesla. The guy really liked it for stoplight to stoplight fun. He mentions the lack of top speed but also reminds us that top speed is rarely used and was worth the trade off of the off the line punch.
They showed some interesting numbers that were either chassis dyno figures or onboard dyno figures. It pretty much shows what I thought all along, it has great off the line torque to the rear wheels but as soon as it gets past 40 mph it's all gone and heading down hill quick. They showed a comparison to the V-6 Camaro and as soon as the Camaro shifts to second gear the torque to the wheels as already more than the Tesla is at that point during a sprint. When you campare the weight specs you will see that the Tesla is more than 1000 lbs lighter, that's where the performance comes from. After reading that write-up I would have to say a 2 or 3 speed tranny would surely make the torque to the rear wheels show better but the weight would slow it down off the line to gain the top speed and it wouldn't be worth it.

The weight of what? The transmission? I feel the original two speed option would truly make this a super car terror... so yes it would add another 100 lbs of weight, but the car is already overall pretty damn light...and that second gear would really help that flat torque curve come to life at higher speeds...

It would be cool if they were to offer the 2 speed tranny as an add-on option...

I have noticed that the Bmw. Porsche, and other tuners are using the seconds it takes for 60-130mph as a performance comparative standard...

The figures i ran of the Tesla's multiplied torque showed it being pretty underpowered from 60-130... in comparison to a Porsche 911 turbo for example...

[ClintK]

Originally Posted by Bowser330

It would be cool if they were to offer the 2 speed tranny as an add-on option...

Wasn't one of the reasons they dropped the 2 speed was because of poor reliability? If I remember right, it was hard for them to find a transmission that could shift at 14,000 RPMs.

Side note... sure the muscle car magazines will complain it can't do 140 mph, but I'm sure a fraction of the owners will even get near 100 mph - and their waiting list for the car shows their design tradeoffs are acceptable.

[Bowser330]

Originally Posted by ClintK

Wasn't one of the reasons they dropped the 2 speed was because of poor reliability? If I remember right, it was hard for them to find a transmission that could shift at 14,000 RPMs.

Side note... sure the muscle car magazines will complain it can't do 140 mph, but I'm sure a fraction of the owners will even get near 100 mph - and their waiting list for the car shows their design tradeoffs are acceptable.

If they wanted to find a transmission that could handle it, they could have..because there are transmissions that could handle 14,000rpm...

I think they realized, like you and others have said before, that most people would care more for performance around the 0-60 range rather than 60-whatever...so they scrapped the idea of the trans more because of that rather than sourcing a transmission....

[WarpedOne]

If they wanted to find a transmission that could handle it, they could have..because there are transmissions that could handle 14,000rpm...

Such a transmission is another thing everyone says exists but noone can show it to me. Nor Tesla Motors. Magna couldn't make one, XTrac couldn't make one. They've both tried and failed.

Now, whom am I supposed to believe? A random forum guy or specialist who tried and failed?

[Bowser330]

Originally Posted by WarpedOne

Such a transmission is another thing everyone says exists but noone can show it to me. Nor Tesla Motors. Magna couldn't make one, XTrac couldn't make one. They've both tried and failed.

Now, whom am I supposed to believe? A random forum guy or specialist who tried and failed?

"Random forum guy?"

Nice to meet you too Mr. 18 posts

Believe whomever you want too warped one.

[Duncan]

The initial post said
"As soon as it had reached 40mph its all over"
If I am reading the specs right peak power is about 80 mph and the bugger has still got
150 Kw at its governed top speed (125 mph)
The torque curve shows constant torque from zero to 60 mph
I suppose you could increase the rear wheel torque by gearing it down and then changing up a gear but you would want to run to 12,000rpm then change down to 7000rpm
Now this is all with the stronger motor but it does beg the question of why you would need a gearbox at all

[2cycle]

Originally Posted by Duncan

The initial post said
"As soon as it had reached 40mph its all over"
If I am reading the specs right peak power is about 80 mph and the bugger has still got
150 Kw at its governed top speed (125 mph)
The torque curve shows constant torque from zero to 60 mph
I suppose you could increase the rear wheel torque by gearing it down and then changing up a gear but you would want to run to 12,000rpm then change down to 7000rpm
Now this is all with the stronger motor but it does beg the question of why you would need a gearbox at all

Maybe the term "it's all over" wasn't really a good term. I've been looking for the link online to see the dyno tests and the comparison to the Chevy but no luck so far. Anyway, their graph overlay of the Tesla compared to a V-6 Chevy Camaro showed the Tesla having great torque to the rear wheels up to 40 mph then a linear decent. Once the Chevy shifts to second gear the torque to the rear wheels was already surpasing the Tesla and remained higher than the Tesla all the way to peak speed which is likely pretty close between the cars seeing as the Camaro was only a V-6 model.
When we set up a trans ratio you need to know the powerband as compared to the desirable rpm drop upon shift. The tesla can overrev quite a bit as noted on their simple graph but the real numbers would need to be looked at to find the true sweet spot. Look at it this way, if the peak power is 250 hp, and 1500 rpm past peak is 230, and 1500 rpm before peak is 230, then you will accelerate much faster if you shift down 3000 rpm and make another run through the power peak area rather than let it keep running a downhill slope.

[gor]

Originally Posted by 2cycle

I picked up a car magazine this weekend because it had done a multi day test session with the Tesla. The guy really liked it for stoplight to stoplight fun. He mentions the lack of top speed but also reminds us that top speed is rarely used and was worth the trade off of the off the line punch.
They showed some interesting numbers that were either chassis dyno figures or onboard dyno figures. It pretty much shows what I thought all along, it has great off the line torque to the rear wheels but as soon as it gets past 40 mph it's all gone and heading down hill quick. They showed a comparison to the V-6 Camaro and as soon as the Camaro shifts to second gear the torque to the wheels as already more than the Tesla is at that point during a sprint. When you campare the weight specs you will see that the Tesla is more than 1000 lbs lighter, that's where the performance comes from. After reading that write-up I would have to say a 2 or 3 speed tranny would surely make the torque to the rear wheels show better but the weight would slow it down off the line to gain the top speed and it wouldn't be worth it.

according to data http://www.teslamotors.com/performan...and_torque.php

Sport:
288 HP (215kW) @ 4,400-6,000 rpm
395 lb-ft (400 Nm) @ 0-5,100 rpm
Overall Final Drive
8.28:1


Size - rear
225/45 R17


125 mpg: wheel rpm= 1683.82

------------
torque (acceleration) rises until 45mph and than going down, HP after 53mph down

max torque at: 5100 24.97*0.0029735/8.28=45.73mph
max hp at: ... =53.803mph