Drag Racing MX vs MXR

[Philip]

It appears that the MXR has (almost) the same horsepower as the MX.

Either that, of my 2017 MX accidentally got flashed with a secret 50hp map at the factory.

The MXR in the video was brand new (Jeremy from OH is the owner, he bought it today). Also, my own MXR feels about the same as my MX.

 

[snydes]

So much for “2 Alta Phil”....

Looks like you need to take Scott up on his charger offer.

 

[Philip]

Alta says my order qualifies me for a free standard charger. They just need to work it out with the dealer who says he paid for it.

Perhaps I should raise the price on my 2017 MX to $11,995.

 

[Kurlon]

So, the big tell tale would be to put the bikes on a dyno. With no ignition an RPM feed wouldn't be available, but you'd still be able to compare torque at a given MPH. Make sure both bikes have the same gearing and you can compare weather or not the MXR is dropping more output or not. The relatively small increase in stated peak torque compared to the larger percentage wise increase in stated HP implies to me that the MXR is potentially punchier at 0 RPM, and sustains it's power a bit longer on the very top rather than being a big jump across the band like the numbers sans curves imply?

 

[Philip]

Does anyone know good Dyno motorcycle capable shops in the SW Michigan or in the northern Ohio? It would be great to also throw a stock 250SXF on that same Dyno as well. And a 250cc 2-stroke.

 

[Kurlon]

Also note that knobbies make for horrible to read dynos, it's a pain but spooning on the cheapest street tire you can onto a wheel and swapping that wheel between machines will help immensely.

 

[Kurlon]

So, while digging through various forum archives to find as much info on the MXR as I could, I found this tidbit over at VitalMX.com:

Model Comparison
Redshift MX-R
Horsepower - 50 hp
Torque @ Crank - 42 lb-ft
Wet Weight - 259 lbs
Seat Height - 37.5"

Redshift MX
Horsepower - 40 hp
Torque @ Crank - 37.4 lb-ft
Wet Weight - 265 lbs
Seat Height - 37"

Husqvarna FX 350
Horsepower - 58 hp
Torque @ Crank - 29 lb-ft
Wet Weight - 236 lbs
Seat Height - 37.8"

KTM 450 SX-F
Horsepower - 62 hp
Torque @ Crank - 36 lb-ft
Wet Weight - 232 lbs
Seat Height - 37.8"

When you look at the specs for the MX vs MXR, note the final drive is 12/53 on both, but the gear ratio is 3.5:1 on the MX, 3.53:1 on the MXR... they've played with the primary gearing. I'm wondering if they're allowing the MXR to spin the motor a touch faster?

 

[Philip]

Those printed specs do not mean much, IMO. We will blow them out of the water real soon. I am going on a dyno on Monday. Already found a throwaway 19" tire to use on the dyno.

The 3.5:1 gearing is the same as 3.53:1, just with one less decimal point. A rounding error. Most likely these are 60:17 or 53:15 gears.

 

[Kurlon]

Nice, look forward to seeing the data!

 

[rayivers]

Re the MXR hp increase, I think Alta may have done what Zero did - move the current-limiting threshold up slightly higher in the motor's rpm range, requiring the greater peak current of the R battery. During riding this would only be noticeable at WOT near top speed, but should definitely show up on a dyno run. I think the gears are 19:67 (manual p. 94, fig. 29).

Ray

 

[Philip]

I think Alta may have done what Zero did - move the current-limiting threshold up slightly higher in the motor's rpm range, requiring the greater peak current of the R battery. During riding this would only be noticeable at WOT near top speed, but should definitely show up on a dyno run.

If true, this would be weird. Why would I want more HP at 70mph? I need more HP at 35mph and below, when I am coming up on a jump and need to give it more throttle to send it a little farther.

 

[rayivers]

Why would I want more HP at 70mph?

I wouldn't really need it either, but a desert racer, SM rider, dirt tracker, etc. very well might (along with Alta brochure writers).

Ray

 

[Philip]

Bingo.

 

[ElectroBraap]

I'd love to see a dyno, I think that will tell the full story. I just was on the phone with some of the boys at Alta and we were discussing how different the MXR actually is compared to the MX. I'd seriously hope that they aren't blowing smoke.

-Electro

 

[Philip]

Alta Redshift MXR and MX on a Dyno - Riding Maps Demystified