Originally Posted by
Vteckidd
the problem with Dyno jets has always been that they TRY to really factor everything in but they cant. They are too easy to manipulate and arent really AS ACCURATE as you want them to be. They are an inertia Dyno not a load based dyno which ideally is what you want.
The way a dynojet works is it calculates how fast you turn the roller in a certain time frame and calculates your hp that way.
Force = Mass x Acceleration
Basically the dyno drum weighs a certain weight (usually 2500-3000 lbs) , it turns at a certain speed for a certain time, uses RPM, and then for lack of a super long explanation, it calculates hp and tq.
The problem with the Dynojets is it negates gearing, and gearing can really effect the TQ and powerband. A car with a 4.4 will dyno differently if you put a 4.9 in it. Tire pressure will effect HP, tire size will effect HP, etc. You wanna make 5 more whp, pump your tires up to 50PSI.
What Mose is talking about is taking the graph as a whole of his car versus gregs car, calculating the gearing differences and measuring HP that way. Basically Mosely in second gear at 5000 rpms makes XXXwhp versus greg at 5000RPMs makes XXXwhp.
Dynojets dont take into effect gear ratios, it tries to negate them or overcompensate for them.
"Area under the curve". Greg may have made 32whp more PEAK, but you can quickly make up for that difference with gearing with a much lower hp producing motor, which you wont see on a dynojet