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Discussion Starter · #1 · (Edited)
There's quite a bit of debate over which dynos read higher or lower -- turbo magazine collected data from the same vehicle on several dynos (detailed here http://www.turbomagazine.com/tech/0306tur_turbo_magazine_dyno_dash/ )

Below is a table based on their data. It reports each mean (average) recorded value for each dyno, and also the percent change going from one dyno to the other.


A few interesting things to note in these data -- the Dynojet readings (there are two, one for a Windows version, the other for DOS) are both lower than the Dynapack reading and higher than the Superflow. Also note that the Windows Dynojet is lower than the DOS version... The DTS and Clayton readings are the highest of all (blame Turbo magazine for the uncorrected DTS tq datum). See the article in link above for more details :)

Discuss...

Hopefully, in the course of discussing this, people will share data, either from their own dyno runs on different dynos or from another source (magazine, technical paper, website), rather than just blindly defend a given (possibly erroneous) belief about dynos.

One important take away message here is that it is very hard to compare the effect of mods going from one dyno to the next -- they vary quite a bit. This should highlight the importance of taking a measure of your car's power BEFORE you install a new part in order to determine how much power you actually gained. The absolute value is all but meaningless, because it will vary from dyno to dyno.

This is why some people's dynos seem unusually high or low, and it leads to all sorts of confusion over a car's "true" power.

Actually, with that point in mind, all of the above dynos are equally "true", but because the absolute value differs accross dynos, you are better off talking about "percent change in power and torque from baseline" than the final number (i.e., "so-and-so gained 10% power from baseline with that header" is more meaningful than saying "so-and-so is putting down 175 whp with that header -- that seems low/high/about right".) The % change should be much more consistent across cars and dynos than the specific values themselves.

Also, (I believe) those numbers from Turbo magazine are all SAE corrected. Using SAE corrections is important because it will hold the effects of weather constant making comparisons between runs on the same type of dyno easier to make. Of course, heat soak, which will be greater on a hot day, is not taken into account by SAE corrections, so ambient temps should still be noted especially if runs were made back-to-back on a day with temps over 90 F.

EDIT: Note that FI cars should use different correction factors than NA cars. For all intents and purposes, uncorrected values will do (i.e., CF = 1.0)

P.S.
Seriously, everyone says dynojets dyno high, but that is only relative to MUSTANG DYNOS. They tend to dyno lower than dynapacks. If you disagree, show me evidence.
 

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good to know. *flameguard*
 

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Discussion Starter · #3 ·
sleepy_celi said:
good to know. *flameguard*
Ha ha ha! I'm just happy someone found this on a search! :laugh:

I sure wish it would qualify for a sticky... :sadpace:
 
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