[davidang22]

Hello all! First post!

I am looking to use a Nissan Leaf motor for my swap. I will not be using the reduction gears, so I was wondering if someone knew what was the torque number is before reduction.

Thank you!

 

[reiderM]

Hello all! First post!

I am looking to use a Nissan Leaf motor for my swap. I will not be using the reduction gears, so I was wondering if someone knew what was the torque number is before reduction.

Thank you!

Depending on the model year, it can be anywhere from the high 100s to over 300 ft-lbs. The number you find on google is before the reduction.

 

[davidang22]

Depending on the model year, it can be anywhere from the high 100s to over 300 ft-lbs. The number you find on google is before the reduction.

I did not know that. I thought that was the measured number from the wheel. But now thinking, since when do manufactures do torque ratings from the wheel. Makes sense now. Appreciate it.

 

[brian_]

I did not know that. I thought that was the measured number from the wheel. But now thinking, since when do manufactures do torque ratings from the wheel. Makes sense now. Appreciate it.

Actually, some EV manufacturers have been quoting torque at the wheels, and it makes perfect sense because it doesn't matter what the motor torque is, only the end result at the wheels. This isn't done with conventional vehicles because it would be a different value in every gear ratio of the transmission; however, most EVs have only a fixed gear ratio so this isn't a problem.

Published Nissan Leaf torque values are all for the motor itself.

 

[brian_]

• first generation (2010 - 2017): 280 N⋅m (210 lb⋅ft)
• second generation (2017-) base model: 320 N⋅m (236 lb⋅ft)
• second generation (2017-) Plus model: 339 N⋅m (250 lb⋅ft)

Anything higher would be using a modified controller.

I have seen references to a change early in the first generation of the Leaf to avoid the highest-torque operating condition, involving a change in gear ratio (7.937:1 for 2011-2012 and 8.193:1 for 2013-2017) and possible change in allowed maximum torque. It's not clear whether 280 N⋅m was before or after that change; one report claims that the 320 N⋅m for 2017 was a 26% increase, which would imply that it was 254 N⋅m (187 lb⋅ft) before.

My guess is that any differences in torque capability before the Leaf+ were probably just programming changes in the controller to protect the battery, rather than real differences in the actual motor.

 

[brian_]

I am looking to use a Nissan Leaf motor for my swap. I will not be using the reduction gears, so I was wondering if someone knew what was the torque number is before reduction.

I assume that you are using some other reduction gearing, instead, such as a conventional final drive unit (differential with ring and pinion gears).

 

[reiderM]

Actually, some EV manufacturers have been quoting torque at the wheels, and it makes perfect sense because it doesn't matter what the motor torque is, only the end result at the wheels. This isn't done with conventional vehicles because it would be a different value in every gear ratio of the transmission; however, most EVs have only a fixed gear ratio so this isn't a problem.

Published Nissan Leaf torque values are all for the motor itself.

Yes. I believe during the Hummer EV reveal they said that it would be capable of 10,000 ft-lbs. This is misleading because of course it's done thru gearing at the expense of RPM.

 

[brian_]

I believe during the Hummer EV reveal they said that it would be capable of 10,000 ft-lbs. This is misleading because of course it's done thru gearing at the expense of RPM.

But it's not misleading - that is the torque where it matters. Engine or motor torque is completely meaningless unless it is in context with speed, so tossing around torque values for engines without the corresponding speed is misleading, or just pointless.

Rivian has also quoted torque at the wheels, as 14,000 Nm (10,326 lb-ft) total for the larger-battery versions. This is comparable to the Hummer EV value, which makes physical sense. It makes a lot more sense than directly comparing the peak torque output of a diesel engine that runs out of breath by 3,000 RPM to the peak torque output of a gasoline engine which can turn twice as fast and so use twice as much gear reduction.

For any EV motor the peak torque will be at zero speed, so some context is implied, but to be useful with a fixed-ratio driveline the maximum motor speed should also be supplied (it's about 10,500 RPM for the Leaf motor with stock controls and nominally 360 V battery).

Of course it's nonsensical to compare torque to the wheels for one vehicle to engine or motor torque for a different vehicle.

 

[davidang22]

Actually, some EV manufacturers have been quoting torque at the wheels, and it makes perfect sense because it doesn't matter what the motor torque is, only the end result at the wheels. This isn't done with conventional vehicles because it would be a different value in every gear ratio of the transmission; however, most EVs have only a fixed gear ratio so this isn't a problem.

Published Nissan Leaf torque values are all for the motor itself.

I assume that you are using some other reduction gearing, instead, such as a conventional final drive unit (differential with ring and pinion gears).

No. I want to pair it up with the manual transmission already in the car.

 

[brian_]

I assume that you are using some other reduction gearing, instead, such as a conventional final drive unit (differential with ring and pinion gears).

No. I want to pair it up with the manual transmission already in the car.

The manual transmission and the final drive (which might be together in a transaxle - we don't know what the car is) will be the "other reduction gearing".

 

[reiderM]

But it's not misleading - that is the torque where it matters. Engine or motor torque is completely meaningless unless it is in context with speed, so tossing around torque values for engines without the corresponding speed is misleading, or just pointless.

Rivian has also quoted torque at the wheels, as 14,000 Nm (10,326 lb-ft) total for the larger-battery versions. This is comparable to the Hummer EV value, which makes physical sense. It makes a lot more sense than directly comparing the peak torque output of a diesel engine that runs out of breath by 3,000 RPM to the peak torque output of a gasoline engine which can turn twice as fast and so use twice as much gear reduction.

For any EV motor the peak torque will be at zero speed, so some context is implied, but to be useful with a fixed-ratio driveline the maximum motor speed should also be supplied (it's about 10,500 RPM for the Leaf motor with stock controls and nominally 360 V battery).

Of course it's nonsensical to compare torque to the wheels for one vehicle to engine or motor torque for a different vehicle.

I think it's misleading in the context of other vehicles, specifically ICE cars. Most of the time, engine torque isn't measured at the wheels but at the crankshaft. You don't hear that a new Ford Mustang has 5,000 ft-lbs. of torque at the wheels. Partly because no gas cars uses fixed gear reductions that the Hummer and Rivian (and almost every other factory EV) are using. When you have a full tr Here is an article about torque numbers on the upcoming Tesla roadster. Gas cars just don't advertise torque figures as the torque at the wheels.

For the Hummer, I'd guess to get >10k ft-lbs. at the wheels they're using something in the ballpark of a 15:1 reduction. Maybe that means that they'll have a proper gearbox with different gears (like the Taycan)? I'm not sure.

For this reason, HP or kW are really the ideal measure of how powerful an engine or motor is since they take into account both torque and rotational speed. Like you said torque alone is a poor number to compare between vehicles, ESPECIALLY when taken at the wheels.

 

[brian_]

I think it's misleading in the context of other vehicles, specifically ICE cars.

If anyone is comparing numbers with no understanding at all, they should do themselves a favour and stop comparing numbers.

For the Hummer, I'd guess to get >10k ft-lbs. at the wheels they're using something in the ballpark of a 15:1 reduction. Maybe that means that they'll have a proper gearbox with different gears (like the Taycan)? I'm not sure.

Not likely - the tires are not big enough for that much reduction ratio with typical motor speeds, and GM won't be running the motors at exceptionally high speed. The Hummer EV is a big premium vehicle; GM is launching with the most profitable model (or at least the one which will lose them the least amount per unit of public exposure), so it has three large motors (each the largest of the three motors in GM's new Ultium component set), totalling 745 kW. Later - more reasonable - models will have smaller motors so they will put less torque to the wheels, and many will be lighter and have different performance expectations so they won't need so much.

10,000 lb-ft is 13,558 Nm. That's 4519 Nm per motor output from gearing, or 450 Nm per motor input to a 10:1 drive ratio (proportional to tire size - comparable to 8:1 with Leaf-sized tires)... that's consistent with a motor moderately larger than the Leaf or Bolt motor (because this is the large motor, and has 800 volts available).

No, there has been no suggestion that GM (or Rivian) is using two ratios. With one motor per wheel at the rear they would need two transmissions just for the rear, and while that can be done (Rimac did it), it's too expensive to be attractive to GM and the dual-motor unit which has been shown doesn't appear to have this complication. Here it is, clipped from a GM promotional image of the five drive units:

That's two inverters on top of two end-to-end motors each driving through typical two-stage reduction gearing to separate outputs... not much space to try to squeeze in two extra pairs of gears and a set of clutches.

For this reason, HP or kW are really the ideal measure of how powerful an engine or motor is since they take into account both torque and rotational speed. Like you said torque alone is a poor number to compare between vehicles, ESPECIALLY when taken at the wheels.

I agree, except that torque is valid for comparison only at the wheels; it is meaningless at the engine due to different engine operating speed ranges.

Marketing people always search for some feature or specification which sounds better than the competition, and focus on that. Marketing has essentially nothing to do with conveying information.

I think the shift to EVs is a great opportunity to shift people from using horsepower to the power units of the world of the past century (or more).

 

[Ivansgarage]

Thought a electric motor could be measured, locked rotor torque... that is how I used to measure it...

 

[brian_]

Thought a electric motor could be measured, locked rotor torque... that is how I used to measure it...

Do you mean locked rotor current? Of course torque can be measured, and in any motor and controller system suitable for an EV the maximum torque will be at zero speed ("locked rotor"), but individuals building EVs are rarely equipped to measure torque. And of course someone planning a conversion and choosing a motor doesn't have the motor yet to measure.

 

[266917]

I agree, except that torque is valid for comparison only at the wheels; it is meaningless at the engine due to different engine operating speed ranges.

I disagree, because from a conversion standpoint, I want the numbers to be as apples to apples as possible. Trying to figure out which motor will be a good fit for which older car, I don't have access to random torque numbers someone determined that varies with how much air in the tires, I want to be able to go "Oh, this GMC Truck (using my conversion for example) came with a 248ci 6 cylinder that made 110hp and 190 lb/ft of torque (NOT at the tires). So this Hyper 9 HV will be a good fit because it's around 140hp equivalent and 170 lb/ft of torque."

I agree that the devil is in the details, area under the curve is more important than peak torque and torque at the wheels, etc, HOWEVER, until I can go hop on Google and find out how much torque at the wheels a 1978 Dodge Dart has, it's not helpful to me.

 

[brian_]

I disagree, because from a conversion standpoint, I want the numbers to be as apples to apples as possible. Trying to figure out which motor will be a good fit for which older car, I don't have access to random torque numbers someone determined that varies with how much air in the tires, I want to be able to go "Oh, this GMC Truck (using my conversion for example) came with a 248ci 6 cylinder that made 110hp and 190 lb/ft of torque (NOT at the tires). So this Hyper 9 HV will be a good fit because it's around 140hp equivalent and 170 lb/ft of torque."

If you're using the original transmission, there's certainly some validity in that.. although you don't have to use the same gear at the same road speed, so it's not really a direct comparison. If not, motor torque numbers are still completely useless without context. Would 1,000 lb-ft of torque be good? If you said "yes, of course, that's a lot" would it matter if that was only available up to 100 rpm and the motor couldn't turn more than 500 rpm? Because at those speeds it would be completely inadequate.

And there's no need for "equivalent " in "140hp equivalent": horsepower is a power unit... so just "140 hp".

I agree that the devil is in the details, area under the curve is more important than peak torque and torque at the wheels, etc, HOWEVER, until I can go hop on Google and find out how much torque at the wheels a 1978 Dodge Dart has, it's not helpful to me.

But you can, so it is. Multiply engine torque by transmission and final drive gear ratios, and you have it.

 

[266917]

If you're using the original transmission, there's certainly some validity in that.. although you don't have to use the same gear at the same road speed, so it's not really a direct comparison. If not, motor torque numbers are still completely useless without context. Would 1,000 lb-ft of torque be good? If you said "yes, of course, that's a lot" would it matter if that was only available up to 100 rpm and the motor couldn't turn more than 500 rpm? Because at those speeds it would be completely inadequate.

And 500 rpm redlines is obviously something that you encounter all the time in car engines, and the point of this was comparing to automobile engines. If you're trying to repurpose old rechargeable screwdriver motors for your conversion, it's more important. For that matter, when you say 500 rpm, do you mean engine rpm or tire rpm? Because, in my opinion, measuring RPM at the tire is the ONLY way to get a good comparison.

And there's no need for "equivalent " in "140hp equivalent": horsepower is a power unit... so just "140 hp".

I used equivalent because most times you're comparing electric motors rated in something other than HP. Horsepower is, by definition, already an equivalent.

But you can, so it is. Multiply engine torque by transmission and final drive gear ratios, and you have it.

Sure, now tell me what the gear ratios are on a factory 3 speed 1955 GMC truck transmission. That's a Corporate 3 Speed, not a Saginaw, it's not the same. Also, which of the several optional final drive ratios would it have been tested with?

It may not be obvious if you're looking at one facet of the automobiles, but most automobiles came with multiple transmissions, sometimes multiple gear ratios PER transmission, and multiple final drive ratios. For my wife's 1994 Mustang, for example, it may have come with a 2.73, 3.23, 3.73, or 4.11. It may have come with a 5 speed manual, an AOD, an AOD-E or a 4R70W, ALL of which have different gearing. So if I want to know the horsepower and torque numbers for the 302W that came in a 1994 Mustang GT, which numbers would you like to use to compute your maximum wheel torque?

 

[remy_martian]

You're awfully confused, not having any knowledge, but arguing nonetheless

Horsepower is horsepower. Period.

All transmissions have a 1:1 high gear. Yes, it's all the SAME.

Rear end ratios vary, but that's easily determined with a floor jack, jackstands, and keys to the car.

The point of an EV is not matching an original ICE. You can't. The torque curves are totally different. The max RPMs are also different by as much as 4:1.

Sorry, but you gotta do the math. Google is not going to tell you the answers to WHAT you specify for the vehicle.

Ask questions, then shutup and listen...and learn. You're in no position to preach or argue with some of the world class grey matter on this forum.

 

[266917]

You're awfully confused, not having any knowledge, but arguing nonetheless

Horsepower is horsepower. Period.

Yes it is, but PS and kW are both measures that represent an 'equivalent horsepower'. This is from the Encyclopedia Britannica: horsepower | Definition, Unit, and Facts "The electrical equivalent of one horsepower is 746 watts in the International System of Units (SI), and the heat equivalent is 2,545 BTU (British Thermal Units) per hour. Another unit of power is the metric horsepower, which equals 4,500 kilogram-metres per minute (32,549 foot-pounds per minute), or 0.9863 horsepower."

All transmissions have a 1:1 high gear. Yes, it's all the SAME.

No, it's not, because the high water marks for EV cars, Teslas, Nissan Leafs, and Toyota Prius, not a single one of those has a 1:1 high gear. So you can't compare that.

Rear end ratios vary, but that's easily determined with a floor jack, jackstands, and keys to the car.

As long as the rear end is actually in it, or if you have access to the car in question.

The point of an EV is not matching an original ICE. You can't. The torque curves are totally different. The max RPMs are also different by as much as 4:1.

Not really - take a look at a Duramax 6.6L and compare to the Hyper9. Shape of torque and climb to peak is very similar. The biggest difference is that the Duramax starts from idle, obviously. After that the torque curve is almost flat, similar to an EV motor.

Ask questions, then shutup and listen...and learn. You're in no position to preach or argue with some of the world class grey matter on this forum.

See, this is the old person mentality that I've shot down about 100 times throughout my life. You assume because I'm new to the forum I'm new to cars? I'm sorry I disagreed with your own personal Jesus, but I've been building cars for 25 years now, and I have the trophies from both racing AND car shows to prove it. As I just proved at least 3 times in this single post, what you think you know doesn't stand up to even 15 seconds of looking something up from verified sources, and when I don't know something I confirm it, I don't just assume the same BS I've heard on a web forum is the gospel. Your blind assumption that what you think you know is The Answer isn't just wrong, it can be costly and dangerous.

So yes, as Brian has said, if you're replacing the entire drivetrain, then it's probably a lot more accurate to measure torque at the wheel, it's obviously incredibly good when you want to argue hypothetical numbers on the Internet, but as complete as my workshop is, I don't have a chassis dyno, and I daresay most of the "DIY" people on this forum don't either. So for comparing drive units, torque at the crank and brake horsepower is a valid comparison in absence of that to give you an idea when selecting motors, AS I DID.

Aside from that, your argument that "horsepower is horsepower" blows your side of the argument to hell. Because that's the point I'm trying to make. Horsepower is Horsepower and Torque is Torque, so Yes Virginia, you CAN compare output of two powerplants without having to go to some obscure measurement that (nearly) no one uses. To Brian's point, if your plan is to completely change the drivetrain, then there are other things you'll have to consider to get a more accurate comparison, but horsepower is a measurement of work, and moving a car is the work you're doing, regardless.

After all that's said, tell me what the word 'knowledge' means to you, because I don't think you know what that word means.

 

[266917]

Do you mean locked rotor current? Of course torque can be measured, and in any motor and controller system suitable for an EV the maximum torque will be at zero speed ("locked rotor"), but individuals building EVs are rarely equipped to measure torque. And of course someone planning a conversion and choosing a motor doesn't have the motor yet to measure.

Luckily you don't need to, since most motor manufacturers will publish it, which is why it's so nice and easy to compare to the engine manufacturers who also publish it.