Since the extended warranty at my dealer includes an annual dyno run I figured I ought to take advantage of it and let them run it through. The results are below: (the image above is a link to a large image if you want to see things better) Peak HP was 92.75 at about 10,500 rpm and max torque was 51.51 ft/lb at about 9,000 rpm. The only change from stock is a K&N air filter, everything else is right out of the box. The VTEC engagement at 6,700 RPM is clearly visible in both the HP and Torque curves. I thought it was interesting that immediately prior to the VTEC valves engaging there was a DROP in both HP and torque.
Nice Scott, Before I made the modifications on mine I could easily feel the dip in power before VTec engagement. After I did the Power Commander mod (with O2 elims) it really smoothed it out. I've got the K&N like you, but also put on Remus cans. I still haven't put mine on a Dyno yet (waiting for the extra cash!) but want to try to get it done this winter and have the PC custom mapped. Gary
The guys that work on my bike are good. They take the time to do things right the first time, and that includes their dyno runs. There was no throw it on the machine, wind it up, take it off. It took them about an hour to run it, and I could hear it winding up a number of times. I suspect it's about as honest a chart as is possible. Gary, one of these days I'm going to put a PCIII on mine and play around with it some. I keep saying I'm going to do so but never seem to get around to it. If there isn't a dyno shop in your area this one isn't that far away, and it is a Dynojet which fits right in with the PC.
i think that is mainly due to the scale being different for hp and tq, as well as the fact that as the rpm's go up, you can loose tq while maintaining or raising hp. ie where on the dyno chart from 9-10 grand, torque is slowly falling off and horsepower is still rising. horsepower = torque x rpm / 5252 basically any engine speed over 5252 rpm you can loose up to a certain amount of torque without loosing horsepower.
I know this is an older thread but just found it! Thanks for posting he original dyne run chart! Yep. A very honest representation. A couple of comments about the results: the torque chart for the Vfr is relatively flat, which is to be expected. That's why it doesn't bump up a lot when the vetch kicks in. The horsepower is still n the rise, as this bike make horsepower most of the way up the rpm scale. Looks to me like the primo shifting point is around 9,500 rpm. I've noticed my bike, also an 07, has a very light crank/flywheel mass. This is evident when you blip the throttle to downshift. If you do it too early, as you would many engines, the crank slows too much before you downshift. This also contributes to the flat torque curve and steady build of horsepower throughout the rpm range. Nothing wrong with it,just different than many bikes I've had. Cheers John
Sorry about the typos! Damned auto correct! A lighter flywheel and crank decreases momentum in the engine and as a result, decreases torque, while having a tendency to boost horsepower. Of course, torque is a sprout of engine design, bore versus stroke, etc. and
Not familiar with that equation: 2 times phi , (3.1416) times number of rpm's times torque is one that comes to mind. Or, PLANE/33000 from my aircraft engineering days. P= mean effective pressure in the cylinder, L= length of stroke, A= area of piston, N= number of cylinders, and E= number of rpm's. Oh the crazy vtec dip slow bird talks about is caused by the slight lag then power surge as the second set of valves cuts in. I did add a power commander to my bike. The power commander 5. I would really recommend it. It smoothes out the transition, and also gives you a richer mixture, more torque down low, which allows you to corner in a higher gear at low speed without the motor balking. You lose a couple of mpg, but its well worth it. Good discussion! Cheers John
I have a 2000 Kawasaki W650. It is like a non leaking oil, excellent electrical system, retro version of a triumph 650 bonneville. The torque/horsepower curve doesn't follow your calculation. Torque goes up incredibly steeply, then levels off, while horsepower Climbs in a normal curve. Different engine. Loads of down low torque. I tried to cut and paste the dyno chart just to illustrate but wasn't successful.
