Whether or not stock location intercoolers are superior to front-mounted intercoolers is a popular discussion topic.
I’ve used a few models of each version with my GTI and logged some information that gives some insight into how the two products compare.
Both tunes operate with similar boost profiles.
Intake air temperature is the variable of interest since it is the product of the intercooler cooling the compressed air from the turbocharger. The difference between the intake air temperature and the ambient air temperature is calculated at 6,000 RPM during a full-throttle third gear pull.
The IAT above ambient has been measured a number of times for the following intercoolers:
- IE V2
- IE V1
- JDEurosport / Treadstone-*
Combining the data points for the stock location intercoolers provides 126 individual observations.
Combining the data points for the Neuspeed and ARM front mounts provides 15 observations.
* Note: The JDEurosport Treadstone TR8L front mount is being omitted from this comparison because the TR8L is designed for low pressure drop with the compromise being, according to Treadstone, “low cooling efficiency“. I don’t believe the TR8L is well suited to the Mk7 GTI.
Summarizing the two data sets into box plots leads to the chart below:
There is a high degree of overlap indicating that the “average” temperature rise during the third gear full-throttle pull is unlikely to be meaningfully different between a stock location IC and front mount IC.
To account for the variance in the recorded data a t-Test is applied to the data observations. The null hypothesis is that there is no difference in the stock location and front mount average temperature delta.
The t-Test result supports the null hypothesis, there is no statistically significant difference in the means of the data sets.
A number of different intercoolers have been used on my GTI and a large amount of data was recorded using them. Analysis of the measurements does not show any significant difference between the intake temperature delta of the stock location intercooler and front mounted intercooler following the data collection method described above.