Ford Fiesta ST 180 (Mk7) Uprated Intercooler
This uprated intercooler kit for the Mk7 Fiesta ST 180 is a direct replacement for the Original intercooler with no cutting of any body or trim. The installation utilises the original boost pipework and air ducting , but by using all the available space and replacing the original 50mm thick core with a 70mm replacement the gains were made.
With different benefits obtainable through using different core designs, we decided to try all that were available. We have been surprised many times before with the results, as many expect bar and plate cores designs to out perform tube and fin with their thermal transfer properties, and because of this accept the significant weight increases that can be involved.
The main reason for uprating an intercooler is to reduce the charged intake temperature as this is directly related to engine power. This is because the amount of power is relative to the density of the air, and density depends on the temperature, pressure and volume. For a given turbo charged engine where the characteristic or specification remain unchanged other than varying the inlet temperature, there is a proven formula to calculate the relationship between the power produced and inlet temperature.
In reality power loss through temperature may be greater. Many engine management systems will reduce power due to temperature increases, in order to protect engine components .
Effect of increasing temperature on power
In the table below you can see how the power is lost as the temperature increases on a 200hp engine. By improving the intercooler, this power can be recovered.
With the ST180 the other variables in the air density equation were critical ie pressure and volume as different intercooler cores offered varying pressure reductions. After studying the test data, the tube and fin design worked best on both the standard and modified cars. Even on a standard car, for which the OEM intercooler has been designed we picked up +5 hp, but on ECU recalibrated vehicles the better intercooler gave +13hp and 27 ft/lbs of torque.