Dyno performance- actual readings

KERMIT1200 said:
Around 50 bhp ,over 50 says to me well setup.Less than 45 -problems.Of course its a bit difficult comparing one set of dyno figures with another from different dynos.


50hp? That means Ian's bike is doughy! 38.6hp is sick. Or am I missing something?

the horizontal axis is labelled as mph not rpm. If this is the case I can't see the two graphs as being directly comparable seeing as you stated that the later curve was measured with a rear sprocket with two extra teeth. In which case requires a scaling factor to stretch out the later curve. Regardless, the increase in peak hp is an improvement!


the Dynojet dyno is all about the rotating mass dyno drum being driven by the rear wheel.
markQLD said:
also, Ian went +2 teeth on the rear sprocket, hence the shift in road speed to engine rpm

well, it makes sense to me, and i believe the graphs are 'comparable enough' as it's the same dyno.
bazzee said:
the horizontal axis is labelled as mph not rpm. If this is the case I can't see the two graphs as being directly comparable seeing as ...
ok, ok. if we are to let a few facts spoil a good story, i concede Bazzee is correct, and the comparison of HP at a given MPH (road speed) is just a tad misleading due to the variation in crank RPM.
so in the interest of correctness, the data file was exported into a spreadsheet and the data series of run 8 and run 6 were aligned to the same RPM. 

to redeem my storytelling ways, i slightly biased the alignment to favour run 6, as can be seen by a detailed eye.
so now, i reckon the graph shows the HP at around 7,000 RPM is close to 45 HP for run 8, and 39 HP for run 6.  or +15% ??  ???

& i think i just worked out why Fred's printouts are always 1 or 2 HP more than what i get plotted.
the default for the graph software appears to have the correction factor set to 'SAE', and i've just noticed Fred's printouts have the correction factor set to 'STD'.
therefore with the CF = 'STD', Ian's Monty racer actually pulled 53 HP at the rear-wheel.  (thumbup)
Thanks for taking the trouble to do that, Mark. It looks like it's benefitted from 4500rpm and up, with a 5hp gain from about 6500rpm up. Well done!


That's all very well for you blokes.. but I have to ride the thing.. :LOL:

Thank you to Redax and Mark M for all their work on getting Monty as good as he can be.. now its my turn.. Lakeside next weekend. I've got an idea that will be a good day..
Testing chassis and motor to make sure we are ready for Round 6 PCRA, and One Hour Enduro at Wakefield Park in the last weekend of August... :p

Ya Gotta Love Ya Racing Laverda.. ;)

Ciao Laverdaisti

Great read this thread, looked it up when Mark mentioned it on another thread.
Good to see how you ended up with the CES headers, thanks Red and Paul.
Well done indeed, a hell of a lot of ground work there. (y) (y)