This dyno testing was done on a play dune port 87 LT500 back in Sept/2010 - 39 pwk - 57 cc Cool Head Copper Gasket - OEM Air Box - VP110 - 927 Oil @ 32-1
This wasnt a HP dyno testing and the sheet says HRD but it wasnt seems my other HRD was in still in his system, This testing was more of whats FMF power curve like vs a Q pipe
so if you wanted to just putt around the fmf would better but then why buy a zilla to putt?
What is with that dip at 7400RPM? My bike has that same kind of dip around that area.
I did not think that FMF would do so good, Too bad you did not have a Stock pipe that day to play with.
What is with that dip at 7400RPM? My bike has that same kind of dip around that area.
Many systems in an engine resonate and come into resonance at different RPMs. When something comes into resonance, it can be constructive and make more power or make less power if it is destructive resonance. The double hump power curve shown most often indicates the ports are optimized for one RPM and the pipe is tuned to be optimum at another RPM.
Many systems in an engine resonate and come into resonance at different RPMs. When something comes into resonance, it can be constructive and make more power or make less power if it is destructive resonance. The double hump power curve shown most often indicates the ports are optimized for one RPM and the pipe is tuned to be optimum at another RPM. JH
I've asked this question about the dip with your pipe in the Zilla shootout. I finally have the answer. Thanks
What is with that dip at 7400RPM? My bike has that same kind of dip around that area.
Many systems in an engine resonate and come into resonance at different RPMs. When something comes into resonance, it can be constructive and make more power or make less power if it is destructive resonance. The double hump power curve shown most often indicates the ports are optimized for one RPM and the pipe is tuned to be optimum at another RPM.
Good to know Jerry, hope you fix that in my cylinder.... hope its done today
Would this also be for the drop in the 4500 RPM?
Would this also be for the drop in the 4500 RPM?
No!
The big dip at 4500 RPM is "calm before the storm". At 4500 RPM the ports are too big, the ports are open too long, the diffuser is too close to the piston causing severe short circuiting and over scavenging, the tail cone is sending the return pulse while the transfers are wide open, the velocity in the carburetor is too low..............every system in the engine is having a battle with other systems, nothing is working together and power suffers.
The torque peak occurs where the majority of the systems within the engine are optimally working together. Developing an engine where the torque peak and power peak occur at the same RPM is easier than producing an engine that has a wide flat torque curve or one that has the torque and power peaks separated by a wide RPM span.
Producing a wide torque curve requires the engine developer to make all of the systems that comprise the engine, to come into tune at slightly different RPMs.
OK here we have Dyno run on the same top end with some adjustments still with the FMF Pipe
(RED)with a 39PWK and Closed Air Box No Lid, and a Q Modified Pipe
(GREEN) with 41 PWK, Adjusted power valve spring, No air box, 9" K&N, The
(BLUE) was the same pipe but....we had a 39PWK closed air box with an open lid, plus we found out the Power Valve Spring was over tightened and collapsed <--Note A good idea to keep a spare Power Valve Spring in the Jet Box!
Torque curve comes on quick and remains pretty flat with the FMF pipe. Looks like it would be a fun trail pipe.........
Man someones gotta come up with bolder colors for these damn things.Too hard to differentiate and follow the curves.
