The math; RPM X torque / 5252.1 = HP. You can’t calculate HP using your numbers. If you are turning 2620 RPM, producing 30 foot-pounds of torque, you would be making 15 HP. At any other RPM, with 30 foot-pounds of torque, the HP would be different.
When I see somebody fabricating numbers, to prove their point, it leaves meIn an doubting the rest of their conclusions, regardless of how well the article is written.
Are we discussing or arguing? That comes off pretty harsh, Al. As I read it, it’s dismissive of his knowledge which has been rather well documented in his build post. I am not sure if it’s your intent.
Al, I think what Bryan is referring to when he says 15hp continuously is that the motor can sustain producing 15hp without overheating. Typically you’ll have a peak power the motor can only sustain for a specific time duration and then another rating the motor can operate ‘continuously’. Not that the HP curve is flat as you’re interpreting it. Bryan can correct me if I’m wrong.
Al, I agree completely for combustion engines, but not for electric motors. Max torque on an electric motor is at/near 0 RPM, and then constant until field weakening starts. HP starts at 0 and climbs steadily until you start hitting that same limit. Generally any PM electic motor chart curve will be the same, only with the RPM range changing.
Kyle, you are correct - continuous rating is what it can make continuously without overheating. Peak (or max) ratings are higher, for some time limit. For the small Hawk20 motor the max power is 25 HP!
For example:
Lemme see if I can figure out my mod powers.
I don’t think that demographic will be changing over to electric for a long time, if ever. The reality is that the entire motorsports industry takes up less than I think 2% of the automotive gas consumption in the world, it might be less than one. The only real push for electric will be for performance gains and technology development.
Personally, I love the idea of an electric kart. It’s different, it’ll present a new challenge as a driver, and the karts will be fun as hell to drive. To your point about sound, the the kart will still make plenty of noise. Think about the VW I.D. R or Formula E racing. The transmission noise, tires, even the air will make racing noises no matter what’s powering the vehicle.
I think there will be an arms race between EV and ICE technology eventually, which I am going to enjoy every second of seeing.
Regarding sustainability, I think track support will be the biggest hurdle. Battery technology isn’t good enough to last a day on a full charge, so drivers will need to supply some way to charge their karts between sessions, change batteries and carry however many replacements they’ll need, or tracks will need to spend a lot of money providing charging amenities in the pit areas for the drivers. Until that can be figured out to be reasonable for either the drivers or tracks, the EV’s won’t be intruding on our gas powered powerplants.
Ya know, no one is asking anyone to pick sides. You can like both if you want.
^ This.
We have enough polariztion in the world LOL
The irony here of saying you don’t know much about a topic, then immediately questioning the knowledge of someone who clearly has done a bit of research on this and is trying to helpfully provide information towards the discussion is new for me to see on this forum.
Nobody here has questioned that you have spent a lot of time in karting and learned a lot in that time. I think you owe people that same respect towards them instead of becoming dismissive of any information presented that isn’t perfectly in line with what you believe to be true. Could Bryan have explained what he meant by continuous horsepower in his original comment? Sure, but you could have asked a question asking him to do that instead of accusing him of fabricating numbers about a topic you yourself admitted you have little knowledge of.
What? I can’t feed this ball of anger in my belly with karting and ruin that too? Just kidding it’s my happy place.
Maybe you should do the math? Why not take couple of seconds to explore how things might be possible, and approach with curiosity vs dismissing and asking for proof when the burden of proof is squarely in your court.
Provided the motor is capable, it is possible to have a consistent HP figure across an RPM range by varying the torque via the controller.
This was my initial interpretation of what Bryan said as well, but he later expanded that continuous horsepower just means the electric motor will be able to continually output without overheating. It will peak at higher hp numbers, but it can’t reliably sustain that power output for an extended period of time. On the chart that he provided, the motor would be able to sit at 4500 RPM no problem for as long as it needed to.
Am I understanding the dyno curve correctly? The electric drops off extremely gradually versus a cliff for x30? The implications of this are?
From what I have read (granted it is not much), there are three ways of controlling how an electric motor functions. Constant torque over a given range with Increasing in horsepower across that range, Increase in torque over a range with a Constant horsepower across that range or a combination of the two. The later being similar to how an ICE motor works.
This is achieved by Voltage regulation up to Max Voltage, A/C Frequency regulation, Base Motor Speed and Motor Kw Rating.
If I am off the mark on this, please feel free to educate me further.
While we at it… from today:
(CNN)Porsche is making a big push to go green. By 2030, the high-performance automaker says it will be “carbon neutral” and that 80% of the cars and SUV it makes will either be electric or plug-in hybrids.
Yes, that is correct. It’s a gradual electrical degradation if you will, vs complex combustion and mechanical limits. With electric you can somewhat trade voltage for current to keep from hitting a sudden cliff as Greg said.
The big implication is that an electric motor has a huge advantage with the total area under the curve since a combustion engine needs to spin at some minimum speed before it makes any reasonable amount of power. The electric motor doesn’t need to use those clutches or transmissions to match engine speeds to ground speed to get you moving or out of a curve, since it has torque for that in spades. However it does fall down eventually at high RPMs as shown. When very high speeds are required, a 2-speed transmission can be used to make up for this (e.g. Porsche Taycan), or you can use multi-rotor motors that has part for slower speeds, and part for higher speed. I don’t see this as an issue with use on a sprint kart. In my case I will need to run a 1:2 gear ratio, to slow down the output.
Thanks for the explanation. Sounds exceptionally “zoom” friendly.
Moore’s law often gets flogged in ignorance because in point of fact, it applies to the evolution of established technologies that are well understood & essentially “mastered”, if you will. Conversely, cutting edge arenas like new materials development (eg. High density battery) have to traverse the Great Wall of Physics (ie. Challenging problems). What’s my point? Gasoline is extremely energy dense. In that regard, any competing battery technology is most likely not just right around the corner.
Particularly in the case of karting, any new, game-changing battery tech will most likely be prohibitively expensive & economic scaling will be requisite to make it financially accessible. Thus, I would expect it to be initially available in larger markets (cars), possibly at the high-end segment, & trickle down from there.
Since karts are at the tail of the line, you’ll be waiting a while even after a breakthrough comes to market.
Nobody watches it anyways… but the engines on dragsters are what makes them amazing
I disagree on the dragster bit, 10k hp that registers on the Richter scale is a must see. There use I agree
