AMD Shroud Comparison

Background:

When I purchased the AMD intercoolers AMD had informed me that they do not offer shrouds.  I inquired as to why that was and they explained that there had been negligible difference when they had tried using shrouds.  The thought was that because of the large frontal area of the core, the AMD frontal area is larger than any other SMIC I have got figures on except for the Wagner RS4 – which requires extensive modification to the car to fit, this larger frontal area leaves little room for air to go anywhere except through the core.

The Setup:

After driving with the AMD intercoolers for a few days I became curious to see if I could record any difference in IAT with a shroud in place.  I wasn’t willing to spend a couple hundred dollars on a set or ER intercooler shrouds, the only ones I thought might be close to covering the AMD core, so I decided to use my stock IC shrouds.  This was not the ideal setup, but if shrouds were to make any difference I thought stock shrouds may be sufficient.

I had a well laid out course to drive where speeds could be tightly controlled.  Part way through, at about 25 minutes in, I parked on the side of the road with the motor running for two minutes, then resumed the drive for four minutes whereupon I rolled into a FATS pull.  From there I spent a few minutes driving the car back to the garage.

The Results:

The results of the two drives are shown below:

AMD Intercooler comparison with and without shrouds
AMD IC Shroud Comparison

Conclusion:

Results look mixed to me.  At the start the setup with shrouds shows a slight improvement over the non-shrouded drive, and the ambient temperature was a couple of degrees warmer when the shrouds were installed.  But around the midway point of the drive the difference disappears and never returns.  This could possibly be attributed to the type of driving being done, the first half was steady state cruising while the second half had some significant dynamic changes and an overall slower pace.

The main question I have is how the results would have looked if a larger shroud had been used.