ORIGINAL: JPKII

The funny things about dynos and HP ratings whether it's in the RC world or the full size world is no two will ever be the same. Dyno numbers are a good for tuning and R&D. The key is to get a baseline dyno, record ambient conditions, and then make your changes. Re-dyno on the same dyno and apply any correction factors for ambient conditions to see if the change was plus or minus. The only way to compare the CEN 5.0 HP number to the OS number is to dyno on that exact same dyno under the same exact ambient conditions. Will the CEN produce 5.0 HP on that dyno? I doubt it. Their 5.0 HP number comes from, I would guess, engineering calculations based on volumetric efficiency as there is no standards in the RC world for HP ratings as their is in the full size (SAE). Most dynos I am familiar with in the automotive and R&D world employ an inertia drum, an Eddie current brake, a water brake (both of the previous are AKA load dynos), or a motoring dyno. All four of these type use different methods to measure Torque and calculate HP. All have their place but no two will ever read the same HP on the same engine. A dyno is also only as good as it's calibration. Dynos need regular calibration (load cells, lambda sensors, temp sensors, etc, etc.). These calibrations can make egos or brake egos and can be skewed to suit the particular need of the dyno operator. If the operator is trying to sell you a part their calibration settings will be set more on the ego side.


Dyno numbers are all relative and should never be taken as gospel.

The true test for any engine is how it performs on the track. I've got a street/strip car that I dyno pretty regularly and my HP and TQ numbers don't mean ***** unless I can back them up on the drag strip.