Since we are starting to see dynamometers being talked about, I thought it may be helpful to have an explanation of the different dynos being referenced, for those who are less familiar with them (like myself). I found this posted on a Evo forum, seems to be a pretty good summary of the Mustang and Dynojet.
We had an opportunity to dyno an EVO MR 2006 that was just dynoed at a popular local Dynojet. We always new the numbers were lower, but it is hard to quantify the difference without back to back tests. This customer was tuned at the Dyno Jet, then was here to pick up some parts. I offered to do a few pulls free of charge to see the numbers from one dyno to another. This NOT a tuner or shop comparison. It is ONLY a dyno comparison for the community to have a point of reference. I found the numbers to be quite interesting.
There is a few things here to note(DYNOJET). The major differences in the two types of dynos are their principals of operation. A true inertia dyno (such as the Dynojet 224x or 248) uses large steel rollers that contain mass. This mass is fixed, it can never change, and for those that remember high school physics, Force = Mass x Acceleration. Since every Dynojet dyno on the face of the earth has a mass that has been precisely quantified using a proprietary process, and that value is stored in the dyno software for each dyno, not only are the horsepower numbers consistent every morning, noon and night, but each and every Dynojet is relative to one another.
Once that power has been measured(DYNOJET), there are two ways to look at it, corrected or uncorrected. Since every Dynojet dyno is equipped with electronics that measure the atmospheric pressure, temperature, and humidity, the results are able to be analyzed as a ?corrected value?. This allows an ?apples to apples? comparison when testing in regions that are at different altitudes, which affects the atmospheric pressure, and different temperature. Uncorrected would eliminate the factors and provide a more raw number. ******Use SAE Corrected for the value, the old STD Corrected will give high numbers and should not be evaluated**
Things to note on the electric type load chassis dynos?. These types (Mustang, Dyno Dymamics) of dynos utilize rollers that usually have very little mass, hence they?re not a true inertia chassis dyno. In order to present any type of physical load on the vehicle, there needs to be a PAU (power absorption unit). Typically this PAU is in the form of electrical coils that utilize eddy current technology (think of this as a big electric brake). These dynos rely on a Load Cell for measurement. For our purposes, the Mustang, has a method to calibrate this load cell for accurate measurement. Once the load cell(there is no need to calibrate this every day) is calibrated properly, the dyno operator must enter certain parameters about the test vehicle that determine the rate of acceleration the dyno will allow, and are ultimately directly responsible for the power and torque readings that are displayed on the graph. The Mustang software takes this a few steps further, but you get the idea for this write up.
The idea here is, you need to be sure you get all the data. Know what correction factor you are running...this applies to all dynos. Be sure the weather station is working correctly for the DJ and the MD, if applicable. Find out what vehicle weight and HP@50 is entered into the MD software for apples to apple results. Be sure you have you DJ on SAE CORR and ask to see the Mustang numbers from the run page. The WCF(with correction factor) and corrected numbers.
You can take it a step further, if you so choose. Now this suggestion I make very carefully, as not every tuner will appreciate a barrage of questions. You can get data like load/MAF scaling/Boost/etc. to help qualify the data further.
So what should you take away from this?? Ask questions, understand the dyno is a tuning tool ONLY. Delta change from stock is what is important, not the actual number. Finally, enjoy the car, whatever the number, it should be fun to drive!
We had an opportunity to dyno an EVO MR 2006 that was just dynoed at a popular local Dynojet. We always new the numbers were lower, but it is hard to quantify the difference without back to back tests. This customer was tuned at the Dyno Jet, then was here to pick up some parts. I offered to do a few pulls free of charge to see the numbers from one dyno to another. This NOT a tuner or shop comparison. It is ONLY a dyno comparison for the community to have a point of reference. I found the numbers to be quite interesting.
There is a few things here to note(DYNOJET). The major differences in the two types of dynos are their principals of operation. A true inertia dyno (such as the Dynojet 224x or 248) uses large steel rollers that contain mass. This mass is fixed, it can never change, and for those that remember high school physics, Force = Mass x Acceleration. Since every Dynojet dyno on the face of the earth has a mass that has been precisely quantified using a proprietary process, and that value is stored in the dyno software for each dyno, not only are the horsepower numbers consistent every morning, noon and night, but each and every Dynojet is relative to one another.
Once that power has been measured(DYNOJET), there are two ways to look at it, corrected or uncorrected. Since every Dynojet dyno is equipped with electronics that measure the atmospheric pressure, temperature, and humidity, the results are able to be analyzed as a ?corrected value?. This allows an ?apples to apples? comparison when testing in regions that are at different altitudes, which affects the atmospheric pressure, and different temperature. Uncorrected would eliminate the factors and provide a more raw number. ******Use SAE Corrected for the value, the old STD Corrected will give high numbers and should not be evaluated**
Things to note on the electric type load chassis dynos?. These types (Mustang, Dyno Dymamics) of dynos utilize rollers that usually have very little mass, hence they?re not a true inertia chassis dyno. In order to present any type of physical load on the vehicle, there needs to be a PAU (power absorption unit). Typically this PAU is in the form of electrical coils that utilize eddy current technology (think of this as a big electric brake). These dynos rely on a Load Cell for measurement. For our purposes, the Mustang, has a method to calibrate this load cell for accurate measurement. Once the load cell(there is no need to calibrate this every day) is calibrated properly, the dyno operator must enter certain parameters about the test vehicle that determine the rate of acceleration the dyno will allow, and are ultimately directly responsible for the power and torque readings that are displayed on the graph. The Mustang software takes this a few steps further, but you get the idea for this write up.
The idea here is, you need to be sure you get all the data. Know what correction factor you are running...this applies to all dynos. Be sure the weather station is working correctly for the DJ and the MD, if applicable. Find out what vehicle weight and HP@50 is entered into the MD software for apples to apple results. Be sure you have you DJ on SAE CORR and ask to see the Mustang numbers from the run page. The WCF(with correction factor) and corrected numbers.
You can take it a step further, if you so choose. Now this suggestion I make very carefully, as not every tuner will appreciate a barrage of questions. You can get data like load/MAF scaling/Boost/etc. to help qualify the data further.
So what should you take away from this?? Ask questions, understand the dyno is a tuning tool ONLY. Delta change from stock is what is important, not the actual number. Finally, enjoy the car, whatever the number, it should be fun to drive!
![[:o]](/images/smilies/redface.png "Embarrassment [:o]")
I'm perfectly happy with the Cobb tune and the difference it makes over the stock map. The baseline numbers don't mean a whole lot, although EVERYONE wants to know how their car compares to the stock SAE rating of 197 hp (approximately 176 hp at the wheels when you factor in driveline loss).
![[giggle]](/images/smilies/icon_smile_giggle.gif "Giggle [giggle]"){kind=icon}
I'd feel a lot better if several other FiSTs had been dyno'd at the same place and time as mine (the more the better). ![[thumb]](/images/smilies/icon_smile_thumb.gif "Thumbs Up [thumb]"){kind=icon}
According to Chris @ Cobb Plano, mine is the one and only Fiesta ST they have put on their dyno. ![[confuse]](/images/smilies/icon_smile_confused.gif "Confuse [confuse]"){kind=icon}
![[:)]](/images/smilies/smile.png "Smile [:)]")
![[chairfall]](/images/smilies/chairfall.gif "Chair Fall [chairfall]")
![[dunno]](/images/smilies/icon_smile_dunno.gif "Dunno [dunno]"){kind=icon}
![[rockon]](/images/smilies/icon_smile_headbang.gif "Rock On [rockon]"){kind=icon}
