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Posted: Fri Oct 02, 2009 3:44 am
by cannondale27
Don't forget that numbers are not consistent. HP numbers will vary greatly from day to day not to mention dyno to dyno. There are so many factors its amazing they actually print numbers. The only way to compare 2 motors is side by side running one right after the other on the same dyno.
What needs to be done to prove to you that this just isn't so in the vast majority of cases? We have at least 4 different dynos all over the country all putting out within one hp the same numbers on different days and even years with same motors. I think its amazing some don't believe the numbers.
I agree its the cam timing. 54hp with ported, stock crank, asso stock rings and cyclone, Aaen exhaust, 92 octane pump gas. But my cam timing is 111 Intake 108 exhaust. All top end.Very weak on bottom. Almost like a 2 stroke with airbox and toaster same motor puts out 49hp. And is even weaker on bottom.
Posted: Fri Oct 02, 2009 1:09 pm
by kdeal
I think the difference is more one brand of dyno to another. My bike has been dyno tested on 3 different dynos with zero changes and the HP & torque numbers are within .1 HP of each other on all runs. They call my bike the dyno mule because of everyone complaining about certain dynos being "off". The one at Snyder's Motorsports was one such dyno. The dyno operator himself claimed it was reading low! NOT. Put my quad on and it's exactly what I got on the other two Dynojet dynos of the same make and model. One in Florida, one in PA and now one in Ohio. I think the other branded dynos may be different. Remember a dyno is only as good as the software put into it. The one in PA was reading 10% too low. How did they find out? They put my quad on it! A call to Dynojet found out the "Firmware" was misprogrammed due to an error in the devices listed in the software. (They did not include the Eddy brake in the original firmware). The firmware was reinstalled on this dyno after a system crash and update to the accessories. After a 5 minute reflash with the new firmware, everything was back to normal.
Posted: Fri Oct 02, 2009 6:44 pm
by cannondale27
There you go. Well said Kdeal. Is also wise to use the Dynojets with tuning link capability just because the tuning link software requires yearly maintainence on the dyno.
Posted: Sat Oct 03, 2009 1:14 am
by Dachshund
With the exhaust timing @ 104.5 it should pull well down low and sign off a little early on top. With the rev limiter set @ 10,500 this motor should last a long time.
Just to be clear it's set at 10,800 and yes that was the plan to have a very rideable long lived motor. I have no complaints with it but then again I havn't ridden the big dogs.
I agree its the cam timing. 54hp with ported, stock crank, asso stock rings and cyclone, Aaen exhaust, 92 octane pump gas. But my cam timing is 111 Intake 108 exhaust. All top end.Very weak on bottom. Almost like a 2 stroke with airbox and toaster same motor puts out 49hp. And is even weaker on bottom.
Steve, is that the same motor you were running at the drags? I know you were running the toaster and airbox. What was your gearing?
Posted: Sat Oct 03, 2009 3:44 am
by cannondale27
Yes same motor. Was just enough to beat that YFZ and thats about it. 14-38 gearing and 20in Holeshot HD's. Since then I lowered gearing to a 40t rear and it helped alot.
Posted: Sat Oct 03, 2009 4:38 am
by Dachshund
Ah, that was the difference then as I was running 18" Holeshot MXR4's and 14-42. It tops out(on the rev limiter)at 69 MPH according to the GPS.