Quote:
Originally Posted by Enslaved
I hear ya. I just think its a bit more nuanced than that. Plus, I think you will start a huge flame war with the dyno accuracies  Everybody and their brother has had an opinion on this subject since the first dyno was created.
In the GM dyno wings, we calibrated (and I'm sure they continue to) our dyno cells with 'gold standard' instruments that were traceable to NIST. Even then, the accuracy and repeatabilty were generally ~1% of the standards(s) - full scale in some cases, % reading in others. However this could vary depending on the range of the unit. I mention this because I suspect most dyno's out there are likely NOT calibrated at a reasonable frequency. Calibration drift is a very real thing, for many reasons. Moreover, with all the variants out there (eddy current, intertia, hydraulic) you will have error between them, as you mentioned.
Add in the mix, wheel size/weight/traction, dyno operator setup and configuration, ambient conditions (let's not forget calibration and accuracy of the dyno's ambient sensors), and probably a few other variables I'm leaving out - you have a healthy scenarion for varation in output. Quite frankly, It's impressive that the dyno manufacturers have things as close as they do. It just means they've done the best they can to eliminate humans from the equation as much as reasonably possible.
At the end of the day it comes down to drivability, seat of the pants feel and track times (if that's your thing). Big numbers are easy to acheive - it just takes money and a sliver of knowhow. Drivability tuning,imho, is where the hard work is and what matters the most on a street car.
Anyways, sorry for the rant  |
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Actually, you are perfectly correct, but within these errors and variances, we still do get some sort of reference that we can rely on, in order to assess the power figures.
And yes, for a street car (which is my goal as well), drivability is key, while chasing the last bit of WHP at the highest points of the RPM band is (to me) of lesser importance.
Saying this, curiosity of what can be achieved with my hardware and software calibration drives me to research the various measuring tools available and their potential effectiveness in reporting the results.
Bottom line, back to your next steps: Would be interesting to see how Ted @ JRE gets you dialed in towards your next dyno session.
From the log, seems that spark for instance, is extremely conservative at ~ 8 Deg.
In my case, I run the stock LT4 1750cc unit + LT4 fueling as well (@ 93 Pump gas), spark being at 14-14.5 Deg. while boost is capped at peaks of 7.5 PSI - Usually more like 7.2-7.3 PSI @ WoT. Lambda stabilizes at ~ 0.82