Want performance mods? Here're my opinions..

I was told it's very accurate and all major manufactures are now changing to it. GM, Nissan, and other have it now. I was told, tha JWT has a few different DynoMeters and they like their DynaPack the most.
 
It will read higher. Someone want to do the math?
Found this:

[FONT=Arial,Helvetica,sans-serif]This is why we recommend people use a rough percentage adjustment to estimate flywheel hp on the Dynojet versus a rough fixed adjustment on the Dynapack. In our experience, a manual transmission FWD car will lose 20-25 hp to the hubs on the Dynapack. A RWD car will lose 25-30 hp and an AWD car about 35-40 hp (the FWD case has been verified on an engine dyno). In contrast, losses on the Dynojet will be in the 12-14% range for FWD and 14-16% for RWD (opinions vary).[/FONT]
[FONT=Arial,Helvetica,sans-serif] [/FONT][FONT=Arial,Helvetica,sans-serif] [/FONT]
[FONT=Arial,Helvetica,sans-serif] [/FONT][FONT=Arial,Helvetica,sans-serif]Let's work through a comparative example for the same car on a Dynapack and Dynojet.[/FONT]
[FONT=Arial,Helvetica,sans-serif] [/FONT][FONT=Arial,Helvetica,sans-serif] [/FONT]
[FONT=Arial,Helvetica,sans-serif] [/FONT][FONT=Arial,Helvetica,sans-serif]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).[/FONT]
[FONT=Arial,Helvetica,sans-serif] [/FONT][FONT=Arial,Helvetica,sans-serif] [/FONT]
[FONT=Arial,Helvetica,sans-serif] [/FONT][FONT=Arial,Helvetica,sans-serif]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.[/FONT]
[FONT=Arial,Helvetica,sans-serif] [/FONT][FONT=Arial,Helvetica,sans-serif] [/FONT]
[FONT=Arial,Helvetica,sans-serif] [/FONT][FONT=Arial,Helvetica,sans-serif]Please keep in mind that these are rough approximations based upon some loose physics and real world experiences. But they should provide a better insight into the difference between loaded and inertial dynos, and hub vs. roller dynos, along with assisting the user in trying to compare results across the different systems.[/FONT]
 
Here's my un-educated 2 cents.

I think for the same reason the the FW horsepower is higher due to power transfer and loss to the wheels, it would be even less from the wells to the rollers of the DynoJet. Also, I've heard that there is more loss of power to the wheels due to Automatic transmission vs. the Manual.

Therefore, the numbers that manufacturer provides when advertising for each car are Flywheel HP and take at optimum levels with 0 loss. I heard that most people Dyno Auto Transmission on 3rd gear because, aparently there are a lot of slipage in 4th and 5th gear.

Again, my knowleage of this is as good as a door knob. Maybe others who have industry experiance can comment further.
 
I dont think were getting into why auto or manuals or whatever can create loss, just the diff between the two dynos.
Just want an idea of how much power you have in caparison to others. Kinda like a level playing field.
 
For me it does it does not matter any more. Unfortunately, I can no longer repeat that test, since my supercharger is going in and my fx is now gutted. However, Technosquare will be doing a Dyno tune on Tuesday. I can take that result, and get another dyno on the DynaPack and then we have the correct results.

In fact, to know for sure, we would need more test cases that would be able to do both tests fairly close together on the same two machines. Maybe oneday, other people on other forums would use our results as basis for their comparisons.:wub:
 
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