A Treadstone TR8C intercooler was picked up to use as the FMIC portion of a bicooler setup paired with an aftermarket stock location intercooler.
This core was specifically chosen to try and reduce pressure drop. The TR8C has a 3″ inlet and outlet to the end tanks and the openings are in the center of the end tank. There are two versions of the Treadstone core, one is 24″ in length and the other 22″, the shorter was chosen to help with increasing airflow.
It is worth pointing out that the shorter core should result in slightly higher air temperatures at the outlet, this tradeoff is acceptable for the goal of this experiement.
Previously the TR8C was flow tested and it did not disappoint, outflowing every intercooler I have tested including the stock location do88 intercooler, the previous top flowing intercooler.
The TR8C flowed 268 CFM, just besting the do88 that has flowed 267 CFM.
A very high flowing core was selected to continue an investigation into optimizing the bicooler arrangement. Previously a Majesty FMIC has been paired with some stock location intercoolers (Unitronic, Integrated Engineering, do88, stock GTI) and the combined cooling results suggested that a higher flowing stock location core did not benefit as much from the addition of the Majesty FMIC as lower flowing stock location ICs.
The Majesty FMIC is a relatively low flowing IC so to evaluate another combination the high flowing TR8C was selected.
Fitting the TR8C to the GTI posed a challenge initially since there are no pre-existing brackets made to support this intercooler. After reconsidering the purpose of installing the TR8C, to gather sample data, I decided a short term solution was acceptable and supported it with heavy duty zip-ties.
The Majesty bicooler hoses can be made to work with some other cores, as my prior experiment using the Project Bicooler: ARM Motorsports FMIC demonstrated.
A couple extra joiners are required to make it work, and people who get nervous about additional hose clamps presenting “an additional point of failure” would cringe at the sight of seven hose clamps attached to each bicooler hose (14 total), but it gets the job done.
With the Treadstone adequately secured it is connected with the Integrated Engineering v1 intercooler. The IE v1 has been among the best cooling stock location ICs that have been installed on my GTI. The v1 has average flow performance.
The GTI is taken out to make a series of full-throttle pulls in third gear up to approximately 6500 RPM. For making comparisons the intake air temperature at 6000 RPM is noted and the outside air temperature subtracted to get a temperature delta at 6k RPM.
Cooling performance is not bad for multiple successive pulls, on average 18 degF over ambient, but given the amount of intercooler real estate that is at work the results need to be better to justify using this configuration for cooling.
In comparison the IE v1 without the front core cools better, reducing the temperature delta by approximately half.
With respect to pressure drop this combination is fantastic, pressure drop between the turbo outlet and intake manifold is practically non-existent.
This experiment was successful in producing data that supports the hypothesis that the airflow distribution between a stock location intercooler and front mounted intercooler affects the performance of the bicooler system.
Additionally the data supports the hypothesis that the greater the difference is in airflow between the cores the less effective the entire system is at cooling the charge air.
The goal of understanding how to optimize a bicooler configuration has not yet been accomplished, but these findings help to make progress toward that goal.