So according to Shawn Church tuning, there is a reduction of WHP between a Dyno Pack and Dynojet. He explains it here.
A comparative example for the same car on a Dynapack and Dynojet.
Car A produces 205 hp to the hubs on the Dynapack. This would equate to between 225-230 hp at the flywheel. The same car produces 195 hp to the rollers on a Dynojet. This would equate to 222-226 hp at the flywheel. Furthermore, the difference in power matches up very well with our calculated difference due to inertial losses. And interestingly enough, we have tested just such a car on our Dynapack and a Dynojet back to back with the same results (actually 196 vs. 206 hp).
Let us then assume that we modify Car A to produce 25 hp more at the flywheel (maybe a good head port and set of camshafts). The car would now produce almost 230 hub hp on the Dynapack, but on the Dynojet it would produce 217.5 hp. Same car, but the difference between the two dynos has grown from 10 to 12.5 hp, largely due to inertial effects.
So in essence, i am doing roughly 195+/-Whp which should be putting me on par with my bolt ons. I drove the car today to give another feel for it. (got the axle fixed). It still feels really linear..but the abrupt speed is or the feel of speed isn't as explosive as before. It's smoother and more civil. It just doesn't feel as fast. Could it be because it is smoother, it's fooling me to think it isn't as fast? The dyno proves there is an improvement from 172-195..it just doesn't feel as "fast" anymore. I also noticed that when i press on the gas, it doesn't rev as fast either..
A comparative example for the same car on a Dynapack and Dynojet.
Car A produces 205 hp to the hubs on the Dynapack. This would equate to between 225-230 hp at the flywheel. The same car produces 195 hp to the rollers on a Dynojet. This would equate to 222-226 hp at the flywheel. Furthermore, the difference in power matches up very well with our calculated difference due to inertial losses. And interestingly enough, we have tested just such a car on our Dynapack and a Dynojet back to back with the same results (actually 196 vs. 206 hp).
Let us then assume that we modify Car A to produce 25 hp more at the flywheel (maybe a good head port and set of camshafts). The car would now produce almost 230 hub hp on the Dynapack, but on the Dynojet it would produce 217.5 hp. Same car, but the difference between the two dynos has grown from 10 to 12.5 hp, largely due to inertial effects.
So in essence, i am doing roughly 195+/-Whp which should be putting me on par with my bolt ons. I drove the car today to give another feel for it. (got the axle fixed). It still feels really linear..but the abrupt speed is or the feel of speed isn't as explosive as before. It's smoother and more civil. It just doesn't feel as fast. Could it be because it is smoother, it's fooling me to think it isn't as fast? The dyno proves there is an improvement from 172-195..it just doesn't feel as "fast" anymore. I also noticed that when i press on the gas, it doesn't rev as fast either..