4 points - 1st is it should be a 75-85 viscosity oil, NOT an 85-140! 2nd is that it's over-filled! 3rd is that both those things will increase viscous drag and cause the diff' to run hotter than the correct oil and level would have. 4th is that the apparent power didn't reflect that because the axles and wheel assemblies were turning slower, so less parasitic power losses there.
Horsepower is torque times rpm. Engine produces the same hp with diff gear change So if you reduce diff gear, you make same WHEEL horsepower, but at a lower rpm (kmh wheel speed) But for the lower rpm you increase the torque. So more torque number times lower rpm = same hp. I think if you measured RPM instead of wheel speed, you would have had the same dyno graph before/after give or take tolerances/the calculations the dyno was doing. Quick maths. You looking for a mehcanic?
the fact it spits out 2 torques at the same horsepower and revs just proves that everything is a lie and it should be measured in how much it puts your head in the headrest out of 10
Nice work fellas. If you want the sh*t-hot traffic light to traffic light acceleration, 3.9:1 is a good choice. The reliable all-rounder is 3.08:1 (or thereabouts). Any diff with a 2 as the first number might give highway cruisability and fuel efficiency, but will tend to be a bit of a slug.
Take that as good validation that your dyno is accurate and reliable. The dyno measures tractive effort and roller suited, then calculates power from that. Although the diff gears generate higher torque, they do so at a lower roller RPM, hence you end up with the same peak power figure. A lot of dynos will show some varience, it's a good sign yours was that close.
Well done, that is the ONLY other comment that showed any intelligence! 👍😎 If they selected different gearbox gears that gave a similar "road speed" on the dyno', it would be even more informative.
