Quote from: AJP turbo on January 02, 2017, 12:39:45 PM
Yea I agree the numbers are low but the awsome thing he did was compare stock to 2 different tuners and at least the numbers are consistently low
They call those dynos heartbreakers fir a reason lol
While the absolute numbers on the Mustang dyno are low, I believe the relative deltas are accurate, as alluded to by AJP Turbo.
As a [rough] point of comparison, I ran on a Dynojet a day prior to my Post #1 run on the Mustang. The results are not totally apples to apples, since AWD was disabled for the Dynojet (no linked rollers), but looking at an average of the peak HP/torque numbers, the Mustang read about 15% lower than the Dynojet, which is in the ballpark of the 12-15% difference I have read elsewhere.
If you start with the OE crank HP and torque (365HP/350TQ) and factor in 20% drivetrain loss and a less generous 12% reduction from Dynojet to Mustang correction you'd come up with:
365 Crank HP * (1-0.20 drivetrain loss-0.12 Mustang correction) = 365 * 0.68 = 248.2 Mustang HP
350 Crank TQ * (1-0.20 drivetrain loss-0.12 Mustang correction) = 350 * 0.68 = 238.0 Mustang TQ
Looking at the Peak HP/TQ numbers from my last Mustang dyno runs with the OE tune and 93 octane fuel, I was at 245HP/242.8TQ, which is pretty darn close to the calculated value of 248.2HP/238.0TQ using the 20% drivetrain loss and 12% Mustang correction.
I haven't done any other correlation work to confirm these drivetrain losses or the Mustang correction factor, but anecdotal evidence leads me to believe these assumptions are not wildly unreasonable, and makes my numbers on the Mustang a little less... err... heartbreaking? Hopefully nobody goes pissing in my Cheerios, because I feel pretty good with how everything seems to be shaking out.
At any rate, it's a good example of why you'd want to use the same dyno for all your testing, because moving from dyno to dyno (even of the same type) could give false positive (or negative) gains.
Quote from: FordFam on January 02, 2017, 12:29:43 PM
Wow way to get granular with the data. Fantastic break down. I've almost always seen an increase in numbers from a mustang dyno to a DJ. These are pretty much the mods I'm doing to the Xsport and I was kind of hoping to see higher numbers I didn't think the base run would be that low but I'm assuming that is the dyno being used.
Personally, I'd focus on the relative changes between the baseline and tuned runs (almost 10% total power increase with tuned 87 octane and nearly 20% with tuned 93 octane!). I wasn't really chasing numbers, moreso just curious about relative gains between all the tunes. I can tell you that my @$$ dyno definitely picks up power improvements for any of the tunes over OE, and my on-road data logs also show that AJP's 87 performance tune was 0.162 sec faster in 0-60MPH time over the Unleashed tune as well (see post #2).
If you buy what I'm selling above about the 20% drivetrain loss and 12% lower reading from Dynojet to Mustang, you should be able to take any of my Mustang numbers and multiply them by 1.176 to get an approximation of what sort of output you might see on a Dynojet.
The nice thing is, the more I stack up the data, the more confidence I gain that my results are correlated, because SCIENCE, lol.
