Yes, like with any other car, Ford has published power figures for the Fiesta ST. Those are the following:<\/p>\n
Stock Fiesta ST Horsepower Figures Published by Ford<\/h3>\n
Horsepower: 197 HP @6000 RPM<\/strong><\/p>\n Torque: 202 LB-FT @ 4200 RPM<\/strong><\/p>\n These figures for the Fiesta ST horsepower (stock) are useful, but not when you\u2019re trying to see exact gains when doing power mods. See, Ford likely measured these at the crank of the engine and maybe even using premium fuel, likely 93 octane. There is no convenient way to measure power at the crank on a fully built car \u2014 The engine needs to be outside of the car for that. The easiest way is to measure the power at the wheels. Because of all the moving components between the crank and the wheels, there is some parasitic loss in power. For this reason, horsepower measurements at the wheels is always going to be lower.<\/p>\n At the end of the day, the power measurements on a \u201cwheel dyno\u201d can be a very accurate representation of the power at the wheels, but are always going to be dependent on doing a comparison run after the mods are complete, on the same dyno. By the same token, any estimation of power at the crank or flywheel will be just that, an estimation. <\/p>\n Additionally, while we can get 93 octane and higher gas in California, it\u2019s as rare as gold. We will be running 91 octane on RallyFist, so both the baseline Fiesta ST horsepower numbers and the upgraded power figures should be done on 91 octane. Remember, we\u2019re not going for ultimate power, so we\u2019re not using race fuels, E85 or any specialized fuel — Just good ol’ pump gas. Our goal is to improve a street car that can be filled at any regular gas station.<\/p>\n The dynamometer, dyno for short, to some a rolling road is the device used to measure the power of a car engine by running the car\u2019s wheels on a big roller. Chances are, if you are reading this you probably know what a dyno is so we won\u2019t dig any deeper.<\/p>\n The important thing to keep in mind however is that readings will vary from dyno to dyno. There is DynoDynamics, DynoJet and Mustang Dyno. I\u2019m sure there are others, but I\u2019ve never had a car that\u2019s a dyno queen, so I haven\u2019t payed a whole lot of attention. This one isn\u2019t going to be a dyno queen either, by the way.<\/p>\n HG Motorsports\u2019 dyno is DynoDynamics. They have a reputation for having a very accurate dyno and many of the local car people that are serious about gauging performance upgrades use it. I know this because when I asked in the private San Diego Car Enthusiasts\u2019 Facebook group who to use I almost got a unanimous \u201cHG Motorsports.\u201d<\/p>\n Now here\u2019s the deal, DynoDynamics reads lower than other dynos, particularly DynoJet. Don\u2019t ask me why. That\u2019s just the way it is. The point is it reads lower and many people who only care about seeing high numbers can be disappointed. What we are looking for here though is accuracy in reading the current numbers and then comparing them to the horsepower readings after all the COBB Tuning upgrades. For that reason, it doesn\u2019t matter if the readings start lower because we are still going to very accurately be able to see the horsepower gains. DynoDynamics does have the ability to also put out a DynoJet estimate which is about 17% higher.<\/p>\n Now here\u2019s something to confuse you a bit more. I already said that the DynoDynamics dyno estimate of DynoJet numbers is about 17% higher. That\u2019s the number that a DynoJet would more or less read, at the wheels. However, DynoDynamics believes that number to be a better representation of an estimate of power at the flywheel \u2014 Which makes a little more sense when you look at the charts and see that the DynoJet estimation is only around 12 horsepower off from the Ford engine dyno readings. Also notice that the chart with the DynoJet comparison actually reads \u201cFlywheel Horsepower\u201d and \u201cFlywheel Torque\u201d \u2014 even though that\u2019s what DynoJet would be reading at the wheels. Because, that\u2019s also DynoDynamics\u2019 estimate of flywheel power. Got it?<\/p>\n If this doesn\u2019t make a whole lot of sense, don\u2019t worry. What\u2019s important is seeing the horsepower gains after the mods \u2014 those will be perfectly accurate.<\/p>\nNumbers Vary from Dyno to Dyno<\/h3>\n
The Dyno Runs<\/h3>\n
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