I saw the Cobra EV300 on Supercars Exposed. Truly amazing vehicle. We can only hope the price of performance EVs comes down from the stratosphere. Give me that performance and a new Corvette MSRP with a decent range, and I'm seriously considering it.

 

Thanks 96_Camaro_B4C. You are correct.

Dear Mr. rlchv70,
You have not achieved 1000ft-lb of Tq from your small block. You have achieved 400 from the block and have 3000 at the wheel.
I can gear my 1000ft-lb motor the exact same way you did your 400ft-lb unit, and I'll have 7500 ft-lbs to play with at the wheel.


TRY AGAIN.

 

Who cares unless it's moving? Otherwise you're not doing any work. And even then, how fast can it move?

 

Ding ding ding ding!

Torque doesn't win races unless it is multiplied by RPM. And what do we call that, boys and girls?

 

No kidding. The point is, he was talking about actually making a 1000 lb-ft (and God knows how much horsepower) engine, not using extreme gearing to achieve such torque at the wheels. You are the one who said you can gear it to make that power, which means we should be asking YOU, "who cares? It doesn't matter if you aren't moving." NOTE: After typing this, I went back and realized I'd missed a few posts. I see where you were going now, since Proud seemed to imply that a 300 hp / 1000 lb-ft electric motor would somehow be equivalent to a 1000 lb-ft small block (which would probably be making something like 1000+ hp, and would kill said electric motor).

Exactly. I'm not even sure why this is an argument?? I guess maybe notgetleft was hung up on you choosing 1000 lb-ft instead of 1000 hp to indicate the levels of output that can be achieved on a small block. Maybe that's what this is all about. He's thinking your choice of lb-ft was an implication that peak torque is all that matters for performance. [Correction...See below... the point is that the ability to make torque AT SPEED is what matters from a performance standpoint. I didn't realize the context of your 1000 lb-ft small block question, possibly because I first saw it when he had quoted it...]

No kidding. But he was talking about an engine actually making that torque (and whatever resultant power).

WAIT, WAIT, TIME OUT... I just skimmed back down, and I had missed the comparison of the 300 hp / 1000 lb-ft electric motor to a small block. I had been assuming that Proud was saying it IS achievable to get 1000 hp from a small block in the aftermarket (since he had posted at one point about hot rodders taking ordinary engines and making them extraordinary). Dang, I need to keep up with the thread before posting... I was on a completely different road here at first.

OK, yeah, in that light, Proud, I see what rlchv70, notgetleft, and Bob Cosby are saying. I see the context in which gearing was brought up to get such a big torque number.

I mean, the instant-on torque of an electric motor is no doubt an aid in acceleration off the line. But 1000 lb-ft * 0 rpm / 5252 = 0 hp.

 

http://www.youtube.com/watch?v=rAqPMJFaEdY

 

What does "moving" have to do with the ease of getting torque from an electric motor versus a mechanical engine?

Power doesn't win races unless it can be transmitted from the source to the ground, which is done through turning shafts, which is achieved with what boys and girls?

C'mon guys...
How much HP is used while the car is in neutral and the small block is at WOT?
How much work is being done by the small block if the car has not moved?
Duh.

You can have an AC motor that is constant torque, variable torque, constant power, or hybrids of the three. Go here to read more. I can maintain the 1000ft-lb of torque across any shaft speed of an AC motor if that is what I need to do. Certainly that means that the power will vary with shaft speed, but that also means I can drive my tires at the very edge of their tractive ability all the way through my speed range of my motor, thereby maximizing my accelerative force being applied by the tires to the ground, and thereby achieving the best possible speed in any given distance. Tough to do with a gas engine... it'll typically overpower the tires while trying to launch, and not be able to spin them as the vehicle's speed goes up - hence the soft-pedaling and clutch control issues.

Even if you want to go DC - like a big golf cart - there will be a small residual loss of the torque across the band, but if you throw the current into the motor, you will have TQ. If you have the voltage, you will have the speed. Mix the two how ever you like to get the results you want... high speed high tq, low speed high tq, low speed low tq, high speed low tq... etc.
There are several on this board that have posted in the past about the almost inifinite control we have over electric motors today, and we have discussed it well in other threads already.

You can simply "program" your way into an hp/tq curve that can be flat, curved, or even custom-made to suit your particular needs. IMPOSSIBLE to do with an I/C engine - even with DOD, variable vale timing, and the best computers and injection systems.

No, sorry friend - it was/is still a lame attempt to "equal" the two powerplants.
rlchv70 took the torque to the wheel via gearing when I specifically said get 1000ft-lb with a small block. I'm talking about the source of the mechanical power providing 1000ft-lb of torque, and my subsequent post clarified it again.
As you and I both said.. you can gear the electric motor the exact same way you can gear the small block and keep the advantage.

THERE IS ONE EQUATION THAT GOVERNS THE ACCELERATION OF THE VEHICLE AND IT INVOLVES THE INTERFACE BETWEEN THE TIRE AND THE CONCRETE. MOTIVE FORCE AND THE RESULTING ACCELERATION IS PROVIDED BY FRICTION.
F=ma, where F acting by the tire onto the concrete is provided by the torque of the axle shaft being transmitted through the shaft into the rim, and then into the tire. The F at the ground is equal to the available torque x distance from the center of the axle to the outer-surface of the tire. This is so basic and fundamental, yet so many seem hung-up on power.

You can have torque without power (1000ft-lbs on a shaft that is not turning), but you can not have power without torque (a shaft can not turn at all without a torque being applied). SO WHICH IS THE IMPORTANT ONE TO HAVE?!?! Now I dare someone to say "you can't have one without the other".



OK, how 'bout we all drop the tangential conversation about motors versus gas engines and get back to the crux of the thread? My initial comment has already been twisted and r@ped into something completely different than was intended anyhow. The challenge was to produce a factory-available small block with 1000ft-lb of torque that is easily sellable, streetable, and carries a warranty - as compared to an electric motor of the same potential - and consider the performance potential of it as well.
If you want to learn something new about electric motors in transportation, let's start a new thread.

Electric is coming. Embrace it, or get passed by.
I'll be owning/driving my V8 cars until I become scientific test material and subsequently push up daisies, and then my kids can decide what to do with them. I love them. I want to own and drive and play with them. But I fully expect to be driving the family out to dinner in a few years with a completely smooth and silent ride in an electric-powered family vehicle too.

On a side note, were the vehicles that George Jetson drove powered by fossil fuels, electric, fusion, fission, or EMP technology? All I saw were the little tiny rings that came out of the tailpipe.

 

Torque * rpm. Which happens to be the bases for HP. Which was my point.

Don't know. Don't care either.

Nothing worthwhile. Pointless, but ok.

I have no arguement at all with this, and have no issues with electrically-generated torque/power either. I'm simply saying that using only a torque figure is fairly meaningless in terms of accelerating my car. As an example, compare the acceleration of, say, a 345 lb/ft L98 3rd Gen with a 320 lb/ft Mach 1. They are about the same weight, similarly-geared. If you just look at torque, what do you think the answer would be?

I completely agree with you on most of the remaining parts of your post.

If you have torque without power, you're not moving, so what's the point of having it in a vehicle? If you have torque with rpm (ie....that shaft is moving), now we're getting somewhere. We call that horsepower.

Like much of the above, I agree with the remainder of your post. My whole issue is that torque - as a number by itself - is over-rated, when it comes to determining how well a car will accelerate.

That's all.

Bob

 

It depends on your definition of "source". If you set the boundary condition at the axle, then the "source" would include all of the gearing.

Theoritically, you could also package all of the gearing at the flywheel. The "source" would then be capable of the 3000 ft-lbs in my example.

F=ma only gives you the instantaneous acceleration at launch.

You have to do an energy (power) balance in order to get the instantaneous acceleration rate at any given point in time. The equations become very complex because you have to take into account kinetic energy, wind resistance, rolling resistance, uphill or downhill, power curve of the engine, internal frictional losses from the drivetrain, and wheel slip.

You can use F=ma AFTER you do this energy balance when you know the resultant "leftover" force from taking into account all of the resistances.

Think of gearing as a lever. You can change the amount of force (torque) just by changing the length of the lever.

 

I am in the market for a GT500 soon. I have to admit, if the prices were the same, I'd go for the EV300 just for the "WOW" factor at the local cruise-ins and car shows. I think it would be a real conversation piece.

Looks just like a regular car, and performs awesome. Downside is that it would not be very practical for a cross-country trip or extended vacation away from the local service and charge port.

The technology is coming though. Nice to see some companys putting effort into the performance side of electric units. We hot-rodders may have to change our ways a bit, but we will always persue the speed demons!

 

Sounds good!

PS - I do know what power is, and I crave it as much as anyone, but power alone does not indicate the performance of a car any more than the torque numbers alone do.

Back to the econoboxes we are being forced to buy now...

 

Well, I guess I have to disagree with that a little, because by definition, horsepower includes both work (torque) and time (rpm), while torque is just work (a twisting force with time/rpm not included). But I know what you're saying, and we're basically in violent agreement on most of this stuff.

Bob

 

Fun electric cars are certainly possible. What real positive effect toward solving some issues is dubious at best, if all the issues are accounted for. One big issue is carbon emissions. You know, the other component in the announcement we discuss here. Higher fuel mileage, lower emissions.

Direct emission by electrics is not the problem. It's when you plug them in to recharge that is an issue. Electricity is likely to be VERY expensive. "Big oil" can morph into "big electricity".

Lighter cars with small gas or deisel engines is the easy route. They will likely catch on quickly if gasoline taxes go way up to force the issue.

I believe the car manufacturers will meet the challenge or perish. It's rather odd the US government is intent to put major pressure on a business they have decided to get into.

IMO, they have backed the domestics into a corner to make smaller and less powerful vehicles to meet the regulations. In order to keep safety up to present standards will mean more expensive vehicles with less content.

Better range with higher performance electric cars is not an area where the domestics can sink tons of developement money. Partially because the money isn't there, but partially because there's no assurance that people will be able to afford some super electric vehicle that will run like a scalded dog and have amazing range.

Path of least resistance folks... the path of least resistance.

Much of the holdback by GM for offering more rearwheel drive cars that would appeal has proven to be wise. Particularly in light of these recent standards. There was a lack of clarity from the government in previous times which demanded caution. I think that caution has proven to be well founded.

What seems to be ignored here is the fact that all the car companies have taken financial hits. ALL of them are either broke or shorter on cash than they were a year ago.

If you look at electric cars as being THE answer I believe some considerations are being left out of the thought process. Carbon emissions...

The electricity to charge them has to be produced somehow. Keep in mind that oil fired plants are not conducive to reducing the demand for foreign oil. Nuclear powered plants are not politically viable, coal fired plants are "horrid" carbon emitters. I don't see windmills being cost effective or efficient enough to make electricity sufficient to fill the gap.

There's a big environmentalist push and a massive budget shortfall that will likely lead to punishing energy taxes. The two cheapest ways to generate electricity are virtually removed from the table.

I don't care how good something may or not be for the environmant, or how it will reverse some trade deficit, people are not going to buy what they can't afford. IMO, some of these initiatives will do more to keep the millions who are out of work, out of work.

I fear more is being bitten off than can be chewed.

BTW, China is building "dirty coal" fired electricity producing plants as fast as they can... their population is ditching their bicycles as quick as they can.

I do hope that cars that are presently owned will not be rendered useless by a stroke of a pen.

Far fetched?

Don't count on it.

 

You have summed up my thoughts beautifully. Thanks.

 

What a gracious compliment! You are welcomed.