Bikers, theoretical HP, cold weather and Bull Crap.

[Momz]

We went to the "Cars & Bikes on the Parking Lot" at Washtenenaw Community College yesterday.

We had no intention of putting our bikes into the show but we did put them into the "Horsepower Shootout".
We had three VRCC/ABATE Valks running back to back. My 98 standard went fisrt with a three run average of 90.3 HP. The next was my 2K I/S with and average of 92.3 HP, then Dave Pettits I/S ran 93.3 HP. And Dave Petitts neighbor brought a beemer HP2 that made 123 HP.

We had a chance to talk to one of the instructors about why they did not print the torque figures, he mentioned that it was supposed to be a HP Shootout and they did not have the time to argue with the contestents why the torque curves did not coinside with the HP figures.

There was a Suzuki B-King with two turbos that made 252 HP and that guy was quite happy with his numbers. However there was a guy that had a Screaming Eagle FLH 110 that only made about 85-86 HP.
He accussed the dyno operator of not knowing how to run a dyno. He was told when he bought his HD that it made 125 HP and 85 HP was not anywhere in that ballpark.

Later that day we went to "Depot Town" in Ypsilanti MI. Damselfly and I parked our bikes in the center of Depot Town and relaxed on a park bench while Dave Petitt went to checkout a used van. Soon a couple of other bikers parked next to us. One was a Yamaha Straoliner and the other was an older HD TC FLHP. They looked over the Valks and came over to the bench where we were sitting, These riders asked what was up? We told them we just came from a HP Shootout at the college. The guy with the old HD said his bike was dynoed at a dealership at 117 HP and all he needed to do was to change to Samson mufflers. The Yamaha rider did not give a HP figure but he said he had a "Power Commander" and V&H pipes.

Dave came back from looking at the van and we sort of stood around BSing and I  looked a the Sratoliner and there were no V&H pipes, and the FLHP looked rather ratty. I  don't think either rider was quite honest, or they were kidding themselves.

It was getting cold and so we decided just to go home. October in MI can be quite unpredictable, and we made tracks ASAP.  

[gregc]

A dyno run just one time doesn't mean much. Dynos are just a tool for tuning an engine.  Even doing a dyno run today, then doing the next run tomorrow, will play hell with the results.  The dyno has to be calibrated/ corrected for air temp, humidity, barometric presure, Cause the base is at sea level.  So unless you made a run on the dyno, recorded all stats, made your changes then ran again and corrected for the changes.  All you have from one run is a bunch of numbers, even bike to bike if the motors were at different temps.

[Momz]

At the Dyno lab, all bikes were inspected. I the bike did not meet Tech Inspection it was not allowed to run. The technicians made sure all bikes tire air pressures were set to 40 PSI. The Dyno was calibrated, and well warmed up to reduce parasitic drag. The cell was well ventilated and the ambient temp for all runs was 23 C.
There were three runs and the runs were averaged.

I've worked in automotive dyno labs, and this was as well run as any I've ever seen.

Yet I would have liked to see a true torque measurement and an exhaust probe so that the air/fuel ratios could be monitored throughout the measured range.

I will say this again,....TORQUE is a true measurement, while HORSEPOWER is only a calculation based on torque and RPMs.

[Valkahuna]

..."I will say this again,....TORQUE is a true measurement, while HORSEPOWER is only a calculation based on torque and RPMs"... .  

+1.   Or another way of putting is that Torque is an actual measure of the work performed, while HP is a calculated figure based upon Torque and RPM to reflect a POTENTIAL.  Torque is what you feel in the seat of your pants.
 

[hotglue #43]

I agree... torque is where it's at.... that's what gets ya down the road.  Max hp is usually high on the rpm range.   and not where I ride.  but max torque from 2700 to 5500 rpm is SWEET!!!!!  That's where I ride!!!!

[Hoser]

A dyno run just one time doesn't mean much. Dynos are just a tool for tuning an engine.  Even doing a dyno run today, then doing the next run tomorrow, will play hell with the results.  The dyno has to be calibrated/ corrected for air temp, humidity, barometric presure, Cause the base is at sea level.  So unless you made a run on the dyno, recorded all stats, made your changes then ran again and corrected for the changes.  All you have from one run is a bunch of numbers, even bike to bike if the motors were at different temps.

+1, but they are still fun! I run one every year.  Best ever was 99.1 HP and 98.8 ft lbs torque.  Hoser