When you see manufacturer horse power figures are they refering to crank, rear wheel or super special blue printed engine at perfect temperature etc etc?
I tend to think a bit of each. It can be confusing I agree. ducati is (I think) rear wheel. Japs depends on the phase of the rising sun and the germans on the holiday plans for poland this year.
Historically Ducati used to measure BHP at the wheel so always appeared down on power, plus they quoted wet weight too. Around 2005/2006 they switched in-line with the competition and started quoting dry weight and power was calculated at the crank, suddenly the power increase on MY2006 999's over the MY2005 model was astonishing!
When I count bhp it goes, "100, 110 120, 130, Many". If you've got more than 130 in my book, you've got enough - probably more than enough. I'm not against more, but I wouldn't bother knowing how much more I had. Like will my bike do 165 or 175? Who cares? How much of my time is spent doing it?
Yes, I really dont know why they cant standardised it. Its impossible to compare bikes not being sure about output being rear wheel or crank,also applies to weight. Are they referring to dry weight with battery ,oi land coolant, dry weight without any fluids, or fuelled weight. Very frustrating tyring to compare particularly as in my book the main two stats are power and weight.
Simon, Most power figures quoted by vehicle manufactures (including Ducati) are crank shaft outputs. They do this for a number of reasons most notably as it would be misrepresentation to claim otherwise. It is only possible to make a truthful claim for a vehicles power output based on a standardized bench engine and dyno set up which uses a standard set of variables like fuel, fuel temperature, air temp, atmospheric pressure. To claim vehicle or rear wheel output has too many additional variables which cannot be standardized in a comparative test. These include oil type, gearbox type, gearbox wear, wheel size and mass, tyre size and mass, tyre wear, chain size and type, condition of sprockets etc etc. That is assuming the engine is in 100% condition and properly tuned. Also it is in the manufacturers interest to claim the higher figures. In most bikes the drive line losses through the clutch, gearbox, sprockets, wheel and tyre are around 10-20% so the spec using rear wheel horsepower is not often used except for bragging rights. I suspect some of the confusion comes from the variability of dyno runs done under no controls offered to the public. The results from many bike dyno services throughout the UK should be taken as an indication only, as many give far too high numbers and cannot make adjustments to standardized the results across different bikes over a period of time, therefore as a comparison are only useful when tuning a single bike on a single day. I am not sure where the confusion about Ducati’s outputs came from but they have usually quoted crank power. Take the 851 Strada for example. Ducati quoted 105bhp but they actually produced as low as 90 or 95 rwhp in a new bike. For the 748 they quoted 98 bhp on the earlier ones and 97 bhp on the later ones with the 748R 104-106 bhp depending on the model year 916 was 114 bhp 996 was 112 bhp All of these were crank outputs and all of them should produce much lower rwhp figures.
Then.....throw in the different dyno operators, different dyno makes, different ambient temperatures, bullshoit factor.................and then pick a number!
View attachment 5258 View attachment 5259 Just for fun same dyno, same operator. Different bikes and shop name changed. Correction factor and what not. Guess which one is wrong.
No idea of the point you are making. If any dyno place passed the clearly awful one off as the other, how long would they survive? Is that waht you're trymg to say?! At Andy B - not really, point I was making was I have had a few bikes dynoed at different places and once they do whatever the correction factor is to allow for air temp etc, and make sure of course the rear tyre is set to the req psi, they deem to come out very close as in within 1 or 2 hp
Totally agree Once you get past a figure like that it doesn't really make any difference in the real world.
No the guy is good but it shows how much difference a bike makes on same dyno. One is ok, one is unwilling to do a proper readout. We sorted it eventually he had to change some gearing in dyno and apply a correction to map. Funny that on monster I got exactly same odd map during one of the DD days on portable Dyno
