I dynoed my '09 ninja 250r today, but the figures dont seem right?

[cameltoe]

I did a dyno run today before I put my full yoshi pipe and jet kit on. The end figures are: max HP 31.2 which is at the rear wheel which is 6hp more than everyone elses. The torque figure shows almost 45FtLb which should be around 18FtLb for everyone elses. these are way out. Have I got a very special bike or is the dyno a peice of shit and a waste of money??

[Sparky Bills]

No idea about the torque, but the hp sounds about what id expect.
Dyno runs are far from a waste. Did you get a before and after run done?
If you are doing work to the bike and dynoing as you go just make sure you use the same dyno. It just shows you if the work your doing is improving your bike or not.

[cameltoe]

this is the "before" run, ie I havnt done any work on the bike yet. The pipe should be hear about tuesday and il do a run with that fitted. I will then do another run after that with the jet kit in. The dyno also has a Air/fuel graph so I know after I put the pipe on if I need to fit the jet or not. Also does anyone think that torque figure is a wee bit flat. Shouldnt it be going up similar to the HP??

[MentalFacility]

where is 45lb of tourque? all i see is around 22...

[cameltoe]

The hp is on the left which is probably what your looking at, the torque is on the right and KPH is on the bottom

[Sparky Bills]

NA, The torque curve looks ok. Its still just a 250cc twin mate, so wont have a huge amount of power/torque.
Will be interesting to see what kind of increase you get after doing the work.

[cameltoe]

No but after having alook at wikipedia it says the bike is making 14FtLb and the rear wheels and mine is making 45FtLb. just wondering if the dyno is crap or using a wrong setting or something or have I got a really strong bike.

[Forest]

No but after having alook at wikipedia it says the bike is making 14FtLb and the rear wheels and mine is making 45FtLb. just wondering if the dyno is crap or using a wrong setting or something or have I got a really strong bike.

Dynos are notoriously difficult to calibrate and shouldn't be used for absolute performance measurements.

[merv]

What gear was the bike in topping out at only 100km/hr? Has that got something to do with it because lower gear, higher torque at the wheel. There'd have to be some calculation to relate that back to torque at the crank wouldn't there?

[RobRod]

to find out if you 250 is an exceptionally torquey beast you would need to compare the results against another 250 the same as yours on the same dyno, being tested the same way under the same atmospheric conditions.


Post your 'after' results to see how much of a difference they make.

[The Stranger]

Random guess here.
The reduction effect of the primary drive, gearbox and sprockets has the effect of multiplying torque.
The values are relative to the rear wheel, not the engine.

If so, the torque values are useless when compared to a bike that has been tested on a dyno which uses the engine RPM on the X plot.

[scumdog]

I did a dyno run today before I put my full yoshi pipe and jet kit on. The end figures are: max HP 31.2 which is at the rear wheel which is 6hp more than everyone elses. The torque figure shows almost 45FtLb which should be around 18FtLb for everyone elses. these are way out. Have I got a very special bike or is the dyno a peice of shit and a waste of money??


Ya dynoed a 250?????? WHY???

I got 73HP from A STOCK 1450cc and I still get around the country OK two-up- and using bugger-all gear changes.

AND get 58mpg.

(you metric types can figure it out yourselves)

[paturoa]

I got 73HP from A STOCK 1450cc and I still get around the country OK two-up- and using bugger-all gear changes.
AND get 58mpg.

(you metric types can figure it out yourselves)

...sure that is approximately 88.484 428 937 cubic inches

[homer]

i dont know enough about the dyno set ups, but surely its more relevant to showpeak HP and REVS , the chart i see seems to lack what i would want to know, that being how the hp curve goes in relation to revolutions.

[cameltoe]

showing hp Vs RPM is more difficult to graph, I was in 4th gear. but surely the manufacturer is going to put the most torque it produces regardless of what gear its in, it makes it more appealing to buyers, Ive never heard of any other stock making 45FtLb torque. There is a youtube clip with a ninja 250r on a dyno and that makes 13FtLb torque. thats quite a big difference

[cameltoe]

this is the other sheet with hp and the air/fuel ratio

[Devil]

Random guess here.
The reduction effect of the primary drive, gearbox and sprockets has the effect of multiplying torque.
The values are relative to the rear wheel, not the engine.

If so, the torque values are useless when compared to a bike that has been tested on a dyno which uses the engine RPM on the X plot.

You are quite correct.
These figures are at the wheel and not every dyno reads the same. Which is why (as pointed out) you should use the same dyno for all your runs after making changes so you can get a proper picture of the effects.

The torque reading needs to be divided by the final drive ratio to get the torque at the engine. The sprockets and chain relate direct to pulleys in any physics lesson. Jump on google or wikipedia and learn about pulleys and their effect on torque if you want to understand why.

[Devil]

And while i'm here, showing it against speed is a pain in the arse. If you show it against revolutions you can work out the torque figure with a calculator.

[cameltoe]

Ive loaded it on a wrong file type so it doesnt work but il download it later if anyones interested

[cameltoe]

And while i'm here, showing it against speed is a pain in the arse. If you show it against revolutions you can work out the torque figure with a calculator.


what about comparing speed with RPM on the road ie, I dont know in 4th now but I can soon find out, but I know in 6th and 50KPH im doing 3500RPM, I know that the dyno dudes went to redline. So couldnt I compare the speed such at 100KPH on the sheet where the peak is then go to 100KPH in 4th, see what RPM im doing and waalaa I have my RPM figure. sure its abit anal and a pain in the arse but I could do.

[The Stranger]

what about comparing speed with RPM on the road ie, I dont know in 4th now but I can soon find out, but I know in 6th and 50KPH im doing 3500RPM, I know that the dyno dudes went to redline. So couldnt I compare the speed such at 100KPH on the sheet where the peak is then go to 100KPH in 4th, see what RPM im doing and waalaa I have my RPM figure. sure its abit anal and a pain in the arse but I could do.

You may find this calculator handy.
It is set up for my XT at present.
I used it quite successfully to locate fuelling issues with the PC map for better low end and top speed performance.

[racefactory]

what? 14.5kg m? That's more than a 250 2 stroke or even 400cc bike!!! Something wrong here... or i don't understand lol...

EDIT: just saw it's not kg m....