A while ago I was playing around with the jets in the amalvalve to get the boost pressure up a bit. While driving to check the boost pressure I figured I could do some test runs in 3rd gear from low RPM to the rev limiter and have my Dynojet measure the time, RPM, boost pressure and AFR.

With the Dynojet data exported to Excel I calculated the speed from the revs and with the speed increase over time I calculated the acceleration. The acceleration mutliplied with the weight (I estimated at 1400 kg, with me and some fuel in) gave the torque at the wheels. But since there is also some air drag I also added that, with a Cd of 0.33 and a total frontal area of 1.94 m2. That gave the total torque at the wheels. With that I calculated the flywheel power and torque. The transmission losses I estimated at 16.4%, as that is what I found on the internet from someone who had his Cosworth 4x4 on the rolling road (357 bhp at the wheels, 427 bhp at the flywheel).



According the the calculation the torque is about 515 Nm, which is about 380 lbf.ft and the power is about 360 bhp, which are very closer numbers for the setup I have (T34.48 with Siemens 55s). The boost is about 1.95 to 2.0 bar, so perhaps the torque could be a little bit higher still if I increased the boost to 2.2 bar.



I did 3 runs in total and the graphs are very close to each other, so no need for a rolling road anymore.