It seems there are plenty out there operating under the assumption that engine bay temps are very hot compared to compressor outlet temps and therefore, insulating your intercooler piping is a good idea. This blog will be short since math is hard to dispute.
First question: How hot does it get under the hood?
Feel free to peruse this research paper on the underhood temps of several vehicles in several scenarios but I’ll summarize.
Idle @ 1000RPMs – 75C/167F (no convective heat transfer!)
Flat road at 60MPH – 30C/86F
Hill at 70MPH – 65C/149F
Second question: How hot does the compressor discharge air get?
The equation for such a thing is
Tin = 70F + 460 = 530 deg R
Pin = -5 psig + 14.7 = 14.2 psia
Pout = 14.5 psig + 14.7 = 29.2 psia
Pout/Pin (compression ratio) = 2.056
Assume an awesome compressor efficiency of 78%
a very efficient compressor running at a relatively low compression ratio outputs air that is significantly hotter than the test vehicles underhood temps in all scenarios by a minimum of 44 deg F. Insulating this heat energy with silicone tubing instead of aluminum is a bad idea and can contribute to early onset “heat soak” of your intercooler and will most assuredly increase intake air temp post intercooler as well.