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Edited Date/Time
6/4/2023 4:33pm
Lets see what my 80hp Stark Varg puts down on XPR motorsports dyno!
That's horsepower? What about torque? Or is electric a different animal to measure those?
Regardless, a pretty smooth, liner power delivery.
We didnt have a way of measuring rpm, so ill have to calculate the torque curves based on known rpm limit and given the speed and horsepower. I'm just too busy right now to do it.
96+ mph is absolute insanity
At 30mph the stark has about the same hp as the yzf 450 at 60mph
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So, how many horse power did it make then ?
67.5 at the wheel.
Thank you
So, not the 80hp mentioned.
But, still a good amount
80 hp is at the motor , and I think they said about they were getting wheelspin so it didn't actually register the true full hp
With those in mind it's very close to 80 ,you lose a good few hp from the drive train
At low revs it has about double the hp of a yzf 450 , and at all revs it makes the yzf look weak
It's like looking at a KTM 150 Dyno Vs a yzf 450
At 40mph the yzf has 30hp and the stark has 65
What percentage will you typically lose through the drivetrain on a motocross bike?
Not an argument or any negative shit, genuine question 👍
Video above is worth watching, but if you can't... here's one picture that gives a little glimpse of what the Varg's potential.
Thanks Brian for doing all of this.
It would be so fun to have a race with a bunch of Vargs all locked in max power ... true Rodeo
Copied from another forum:
...A15% loss from the rotor air gap to the rear wheel is pretty much the norm. I.e. 80 Horsepower - 15% = 68 RWHP. The claims appear to be quite accurate when using power at the rotor...
Bottom line is that there is a whole lot more behind this dyno test than meets the eye. In many ways measuring electric is a different animal.
I’m wondering how all that HP, even at low “rpm”, is going to work on a slick, muddy track.
Pretty much expected from an electric motor advertised as up to 80HP.
Seems like a bit of a "heart breaker" Dyno as well. You might be able to add 5hp on the 450, and 5hp for the Stark on a different Dyno.
Pretty impressive stuff, though. I bet that would be fun for a little desert wide open loop!
Chad’s dyno is definitely on the lower side. We use it a lot, his dyno room setup and repetability is top notch.
Just put it on a weaker map
Although, one advantage 4 strokes have is the time between power strokes can give the tyre time to recover from slippage, particularly at low rpm. An electric motor with traction control could easily outdo this though, it could make adjustments at a fraction of a revolution
The channel 'DJWhPw' is very close to 80hp @ ~79. The dynojet manual defines this channel as an "estimated measurement from a competitors dyno". CWhlPw is SAE corrected power. I think correction factors shouldn't be used for an electric motor, but it's probably pretty small anyway at 75*. Or maybe they zeroed it out.
The absolute values aren't that important anyway. The comparison to the yz450 is what's meaningful
I get that as so many just want to argue, I've done a ton of testing on a Dyno and let's look at the yzf 450 ,it's claimed it has about 62hp? So it lost 9hp , so 67.9 add 9 is 76.5hp
However what we really need to look at is area under the curve ,that's what you feel ,not peak hp at a certain. Rpm , the stark has imo almost twice the "real hp" than a yzf 450 ...which comes as no surprise when you see a Tesla plaid Vs a normal supercar
The 50hp stark is very close to the yzf 450 imo
Pit Row
Pretty much. Ive pulled holeshots on my 50hp Alta against a yz450. The Varg in 60hp mode definitely feels faster than a yz450 imo.
Call me dumb.
But what you have said makes zero sense.
A dyno only measures torque. That's all it does nothing else.
To find out the horsepower it uses a formula of the torque value at the certain rpm to find the hp.
So how the hell do u get a horsepower figure without knowing the rpm.
U should have only found the torque value.
They use the rpm from the dyno drum
Inertia style dyno. Calculates horsepower from measuring acceleration rate of the drum. Have to back calculate engine tq
Stark claims "275 Nm of torque on the counter shaft", the gearing is 49/13 (Bryan correct me if I'm wrong!)...
275 * 49 / 13 = 1037Nm theoretically at the rear wheel.
Stark claims "938 Nm on the rear wheel"...
938 / 1037 = 90%, so 10% loss through chain/sprockets.
One benefit of electric is that the throttle can be programmed to be fully proportional, 0-100%, at all rpms. Not possible with an IC engine and cable throttle. The carb/tb will become increasingly oversized the lower in the power/rpm range you go, and therefore throttle resolution drops also. An electric bike can easily get away with twice the torque/power at a lower rpm due to it being optimally spread across the full throttle twist.
@theycallmeebryan the torque graph versus a 450f should look something like this...
The varg uses a 14/48 sprocket setup stock, with a 3.5:1 reduction gear (as ive been told), and waiting for confirmation on the rpm limit of the motor.
When using the 95mph peak of the dyno and setting it equal to the rpm limit of the Varg motor, you can then calculate rpm at any speed as its irrespective of any gearing at that point since the Varg is direct drive with no transmission. And, since we have HP, we can then do the simple torque conversion.
I have the raw data in a string text file, i just need to find the time to normalize it across maps and calculate the torque numbers.
Im super busy with work right now, will be on a business trip all this coming week, plus my wife and I are moving at the end of the month, so my life is fricken crazy right now. I have to deprioritize the Varg a little bit.
or you could ignore motor rpm and calculate rear wheel torque instead, mph and rear wheel circumference is known.
You wheel speed (MPH) is kind of irrelevant in this comparison. The YZ450 is dependent on what gear it is in for a given MPH. It could be in second gear at 9,000 RPM making 55HP or in fifth gear at 6,000 RPM making 40HP. The numbers are based a complete guess, but give you context to my example.
All I am saying is, unless they are geared identical, the HP at a certain wheel speed is irrelevant.
Comparing an electric motor's torque across it's rpm range, to a gas engine across it's rpm range is a meaningless, the electric bike has one gear, the gas bike has 5 gears.
It's better to compare rear wheel torque and rear wheel speed at all speeds and all gears. Rear wheel torque is proportional to bike acceleration, acceleration is what riders feel!
It has this much torque bas
ed on
14200rpm max
Max speed was 96mph
Max hp came at about 1/3 Max speed 14200/3 = 4733rpm
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