first 2018 shootout

[stroker]

http://www.vitalmx.com/features/2018-Vital-MX-250-Shootout,5636

 

Vital Mx gets the hole shot!

[tom02cr250]

They weren't the first lol, Dirt Bike magazine was last week.

[moto671]

What do you guys think it will take to get the low to mid power up to par with my 15? I ride a lot of sand here in New England and wish my 15 had more bottom and it looks like the 18 engine isn't going to help. 

[Eddie8v]

What do you guys think it will take to get the low to mid power up to par with my 15? I ride a lot of sand here in New England and wish my 15 had more bottom and it looks like the 18 engine isn't going to help. 

ECU remap and a high-compression piston and you should be good.

[shkapars]

I will repeat my post from Vital forum here:

School. 
Physics.

HP = NM x RPM / 7121

Take a look at Honda and KTM torque lines at 11 000. Them crosses. Take the formula and put same numbers in. Equals KTM has more ponies  ??

P.S. I've always been red ?

Edited November 7, 2017 by shkapars

[Pontificus Maximus]

The guy from Vital said that he overlaid the KTM/Husky hp graphs from last year because he had some kind of problem with their dyno runs.  Shouldn't dyno runs always be performed on the same day under the same conditions?  Looks like the Honda's torque is greater than the KTM/Husky at 10k - 11k but that is not reflected in the hp graph.  The Honda design looks like it has tons of potential.

[shkapars]

yes. If line crosses in torque graph then them have to cross on Hp graph. If is torque line then you can calculate Hp line in minutes. If calculate KTM max Hp at 13 000 from torque line then there is only 39,6 not 41,2

Edited November 8, 2017 by shkapars

[Eddie8v]

HP = TQ x RPM / 5,252 so HP = TQ at 5,252 rpm.

 

Engines make torque, not HP. HP is but a calculated number based upon torque and rpm.

 

 

[shkapars]

yes. This is what I wona say (sorry for my English) HP is calculated number. Divide number is different if measure torque in ft.lbs or Nm and what you want see in result kW or Hp

Edited November 9, 2017 by shkapars

[shkapars]

Recalculated Hp for KTM from torque line is not more so impressive. Bold line.

 

[SlowDinoDog]

Yes...Vital MX admitted in their forum that they mixed data from 2017 tests in the overlays. The curves should have an asterisk reflecting that. They admitted it after someone recognized the KTM and Husky data was identical to last year. Looks like they may have been sloppy with their math, too.

 

All these bikes were not tested at the same time on the same piece of test equipment.

 

Their write up says they only tested the bikes with the 'standard' map and some bikes made more hp with their 'optional' maps.

 

Kinda bogus implementation of a test...maybe in a rush to get the hole shot...this is lacking credibility.

 

 

[shkapars]

and there is no more 2017 250 shootout torque graphs  as well as no individual bike dyno graphs. But is for 2016

[andis]

Did RaceTech or someone else FAKE the 2018 VitalMX 250 shootout dyno chart?

 

As some of you may have already noticed, the Horsepower graph published in VitalMX article “2018 Vital MX 250 Shootout” placed the KTM and Husqy in the position of god with both horsepower lines “barely touchable” by others and the numbers so much greater…

However, since I am a red rider myself, it hurt me to see the numbers so low on the all new engine – what could have gone wrong? So, being a mechanical engineer, I started to investigate the torque graph and found out that the red machine actually made more torque than both Husqy and KTM between 10k and 11k RPMs, so immediately I scrolled up to the horsepower graph to evaluate by how much it beat the Austrian bikes but felt surprised to see that it actually makes less, even way less power in the same 10k – 11k RPM region.

 

Now how is that possible? Some that have spent their time in physics classes or engineering orientated universities will remember the automotive power formula:

Power [HorsePower] = Torque [foot-pounds] X Engine Speed [RPM] / 5252

So obviously, if one engine produces more torque at the same RPM, it should beat the other, right?

I decided to use some power tools and create a brand-new horsepower graph, based on the published torque curves.

Using 3D CAD and importing a background picture of the graph, splitting the X axis in 500 RPM intervals:

Then carefully positioning points on the respective torque curves and measuring the Y axis distance to the 6 ft-lbs mark:

Then it is just a matter of determining the scale factor and letting MS Excel turn that into foot-pounds and horsepower!

And here is the result, as you can see, the Husqy and KTM power curves look nowhere near to how it was published:

Now that looks a little closer to the truth. ? As clearly visible, both Honda and KTM curves now cross at 11 000 RPM, like they did in the torque graph.

And what do you know... Look at the KTM and Husqy power curves below - recalculated versus published. What a difference, especially on the Husqy..

So, based on this...

1)      Did they really have trouble producing the power curves for KTM and Husqy, so they just over-laid last year’s curves on this year’s graph? If so...

2)      How come the power that we see on the chart does not relate to the KTM and Husqy torque output?

3)      And if they did obtain the torque curves, but had trouble arriving at power curves like it was rumored, why did they not simply calculate the power from torque like I did just now?

I would very much like to see the answers to these few questions… ?

Otherwise... something smells fishy to me! 

[fredgreen]

It may have something to do with KTM spending huge dollars on advertiesing for the pass 10yrs. 

 

[Pontificus Maximus]

Credit due to the MXA guys who were the only ones at that ride day to notice the Honda goes flat up top as the dyno charts show.  With the downdraft intake, finger follwers, and dual exhausts I would have expected the Honda to shred (am I too old to use that word?) up top.  Wondering why...

[SlowDinoDog]

Here's what Vital's 24yr old test rider (with Pro MX and SX experience according to bio) said about the Honda. He picked the Honda #1.
"The engine did lack bottom end grunt, but for myself, I'd rather lack some bottom end and have a massive mid-top end like this bike has. The advantages of having a more mellow (smooth) bottom end worked in my favor at rough tracks like Glen Helen, with ruts that have a slick, hard base. The bottom end power is enough for me to get the job done in lower gears but I did make sure I kept it singing if I shifted above third to keep the CRF pulling strong."

[moto671]

Here is the dyno from the yoshimura website. Looks like a little gain everywhere.

Edited November 11, 2017 by moto671

[NoMuff2Tuff]

I wouldn't get caught up in all the dyno numbers for different reasons. There were many bikes in the past that were dyno kings but on the track there performance didn't show what the dyno said. Dyno's have there place and are a good tool for testing and making changes but it's not the holy grail on a bikes performance. It looks like Honda has put out a good 250f and the door is wide open for modifications and the bike will only get better. It will interesting to see the new GEICO Honda 250f's run next year because they should fly. I can only imagine all the R&D going into the new cylinder head.

Edited November 11, 2017 by NoMuff2Tuff

[fredgreen]

Without the time axis on the dyno chart the whole exercise is a waste of time. 

Example

Bike A has 42 hp peak, and takes 5 seconds to get from idle to limiter 
Bike B has 40 hp peak, but takes 4 seconds to get there

Which bike would you rather race ?

[tom02cr250]

I'm pretty sure that is irrelevant. If one bike revs up faster, then it's making more torque which gets reflected in the numbers/dyno curve.