Performance automatics

[Mr.Jay]

Originally Posted by 1660

Aren't you being a little insecure? You want it to have the word STANDARD?

or at least a mention thats more than the 3 letters that make up LSD

[serialk11r]

@Want.FR-S it's not that simple. The Tesla is almost certainly electronically limited in torque because the tires will slip if you give it any more torque. The motor's true maximum output is when you extend the downsloping curve all the way up. Theoretically you can have infinite torque at 0 rpm, but there are obvious reasons why you can't really do that. An electric motor's torque to speed is ideally an inverse relationship, not considering friction and resistance.

Where a superconductor comes in is it gives a enormous increase in power density, because the wires now do not dissipate heat and can be made extraordinarily thin. In addition, they can handle much more current, which means that maximum torque level can be sustained for even more RPM.

[SUB-FT86]

It's nice to see a friendly conversation about auto's. Like you Madfast, I would want the auto only if it lived up to yours and my expectations. My RSX auto is garbage!!!

[Type[R]+]

DSG > conventional automatic any day of the week, except sat night at the drags lol!

[Dimman]

Originally Posted by SUB-FT86

It's nice to see a friendly conversation about auto's. Like you Madfast, I would want the auto only if it lived up to yours and my expectations. My RSX auto is garbage!!!

Now I see why you are so hung up on the torque of this motor/car...

Have you compared driving your RSX to a 6 speed manual Type-S? I would bet night and day difference.

Torque converter automatics are heavier, sap a lot more power from getting to the wheels, and have a bit of 'lag' when they aren't locked (which is often as they try to shift smoothly). All this is much more apparent in smaller cars and smaller displacement motors, and why I personally hate autos.

This one will probably be better than yours, has an extra gear, but still shares the basic limitations. There may be some aftermarket ECU work-around later, like what Lotus did to the Evora's Camry trans.

Was your 350Z auto as well?

[Exage]

Originally Posted by Dimman

Now I see why you are so hung up on the torque of this motor/car...

Have you compared driving your RSX to a 6 speed manual Type-S? I would bet night and day difference.

Yes, the mystery is unfolding now Dimman... However nothing is going to sway the fact that neither of the K20 engines in the RSX has enough torque down low for SUB-FT86 regardless of transmission type.

[Dimman]

Originally Posted by Exage

Yes, the mystery is unfolding now Dimman... However nothing is going to sway the fact that neither of the K20 engines in the RSX has enough torque down low for SUB-FT86 regardless of transmission type.

The whole k20 auto thing reminds me of the worst automotive travesty Toyota has committed in recent history. 2ZZGE, meet your optional 4 speed automatic...

[82mm 4g63]

Originally Posted by Dimman

The whole k20 auto thing reminds me of the worst automotive travesty Toyota has committed in recent history. 2ZZGE, meet your optional 4 speed automatic...

I just need 1 speed..........Fast

[n2oinferno]

Originally Posted by 82mm 4g63

I just need 1 speed..........Fast

That's gonna suck when you need to back up.

[Dimman]

Originally Posted by n2oinferno

That's gonna suck when you need to back up.

Donuts my friend, donuts.

[Dave-ROR]

I just can't believe there are people that want a sports car with an automatic. Makes me kinda sick. They might as well isolate the hell out of the car too, what's the point of letting the driver experience any part of driving the car...

I'm old(ish?) and still hate automatics, and always will, no matter how good and fancy they are.

[ichitaka05]

Originally Posted by Dave-ROR

I just can't believe there are people that want a sports car with an automatic. Makes me kinda sick. They might as well isolate the hell out of the car too, what's the point of letting the driver experience any part of driving the car...

I'm old(ish?) and still hate automatics, and always will, no matter how good and fancy they are.

My friend, I understand your view but...

Originally Posted by madfast

PLEASE dont turn this into a Auto vs Manual pissing contest. If you have nothing constructive to add just walk away...

[Want.FR-S]

Originally Posted by Want.FR-S

So I said the torque band starts flat (almost) from 0 rpm does not mean it remains flat all the way (infinite power from the battery?). That does not negate the fact that in Tesla roadster does not have transmission gear because their motor has a flat torque curve from 0 (almost) to 5100/5400rpm.

Here is the link from Tesla motor about their technology:

http://www.teslamotors.com/roadster/technology/motor

So if we delve into the details of this electrically-couple transmission:

1. on the input side, we have a ICE burning fuel using 30% of its energy (according to Tesla) to create mechanical rotation torque
2. this rotation power is turning a generator to generate electricity, stored in a big capacitor or a secondary battery, and power will be loss during this conversion.
==> although using superconductor can reduce loss on power during electrical energy conduction, but by how much *in this application*? what is the electrical energy loss caused by the wires in this short distance (relatively speaking) within this device? what is the frictional loss of energy that cannot be saved by superconductor?
3. using control logic to tell another motor to spin at a different rate and consume energy from that big capacitor or battery. That is another energy conversion and energy loss is deem to happen. 12% loss on energy again by Tesla.

So in short, you have directed the energy from mechanical to electrical, and then from electrical back to mechanical for the sake of changing gear. The equipment required could be huge (2 motors/generators with a big capacitor/battery) plus the associated energy loss for the whole transaction. Plus the costs of doing all of these. What is the efficiency gain by this approach?

Again, why so complicate?

P.S. I failed to see how you can use superconductor in this application. Granted superconductor causes little or no energy loss during electricity transmission. But that is not the main point here in transmission design. There are other important factors to consider rather than the power loss in wires. Superconductor is not the *magical* thing that can fix everything.

P.S. 2: just a side note, if you really want to drive the wheel using electrical motor, why not hook it directly to the electrical engine, and wait, isn't that the Tesla Roadster? Silly me.

Originally Posted by serialk11r

@Want.FR-S it's not that simple. The Tesla is almost certainly electronically limited in torque because the tires will slip if you give it any more torque. The motor's true maximum output is when you extend the downsloping curve all the way up. Theoretically you can have infinite torque at 0 rpm, but there are obvious reasons why you can't really do that. An electric motor's torque to speed is ideally an inverse relationship, not considering friction and resistance.

@serialk11r: would you mind to explain this a bit further? Obviously you would not want to generate too much torque at 0 rpm to spin the tire. How does that relate to your statement high-lighted in bold?

Originally Posted by serialk11r

Where a superconductor comes in is it gives a enormous increase in power density, because the wires now do not dissipate heat and can be made extraordinarily thin. In addition, they can handle much more current, which means that maximum torque level can be sustained for even more RPM.

Hmm.. wait, you are confusing me now. Originally you want an electrically-couple transmission with superconductor implementation. And now you are talking about the benefit of using superconductor in a traditional electric engine tie directly to the wheel? You are not making sense here.

True, superconductor (if can be done in room or high temperature) possess those benefits and reduce energy loss. But the fact is, with electric engine and their ability to generate torque at low rpm, there is really no need to have a gear box, and not even a complicate mechanical->electrical->electrical->mechanical drive-train. Of course if we can exchange all the wires with superconductors we can make the electric energy transfer with less loss. But that is not the point here. Why would you use superconductor in this energy sucking mechanical->electrical->mechanical transmission?

One note though: do you know why Tesla motor cannot maintain that torque in higher rpm? Was that current limited or other factors?

So even with a superconductor that can drives way over 600 amps to the motor, you should still need to limit the power band to a certain degree. Why? because you do not have infinite energy stored in the battery. If you increase the current too much, you can drain the battery with little time, and you know that right?

And lastly, for my P.S.2 point in the previous post, I just realize that the power train of GM's volts is just like your idea: using an ICE to run generator to generate electricity and then power an electric motor to move the car.

[serialk11r]

So it's like this, when the motor is at 0 rpm, and you feed the coil voltage, there is the inductance of the coil (which is quickly "overcome") and the resistance. So the maximum torque of the motor is related to whatever the maximum amperage the coils can handle. As it gets moving along the rotor is rotating in the same direction as the current (in some sense) and creates a back emf so the max current drops.

A superconductor removes the motor's power limitation, but telling a battery to supply that energy is, precisely as you say, going to drain the battery too fast. Not only that, batteries have a maximum current supply issue that cannot be overcome without adding more batteries. Batteries have crap energy density (which theoretically can increase a few times, but we won't be seeing that for a while), and afaik the issue of degradation still has not been tackled. A gasoline motor can have very high specific output and very reasonable efficiency, but being tied to a finite number of gears definitely hurts its prospects. In order to create an excess of torque for a significant speed range like the tesla has, you need quite a bit of displacement/etc., and keeping that kind of engine fuel efficient and reasonable for daily use is much more difficult. Given that the Tesla's motor weighs a ridiculously low 70 pounds or something, I think a fully electric drivetrain coupled to a high rev motor can have similar weight and give you a faster car in the end (with much much better fuel economy).

The main thing standing in the way is the size of the generator; if we gear it so that the engine spins at 1/3 the speed of the generator, so we can use a smaller one, there are more losses. So this is just a pipe dream waiting on stuff in the future