Heat Soak

[The_Stig]

I hear this term heat soak said now and then. could some one explain this to me? and if its a bad thing how to be avoided? thanks!

[Chikko]

Re: Heat Soak

I'm by no means an expert... but I'll take a shot: Heat soak is when the exchanger cannot lower the temperature of the incoming air. It tends to happen with smaller intercoolers (or larger volumes of air flowing through the intercooler) at higher ambient temperatures. The intercooler slowly heats up as it is operated. If this heat cannot be dissipated to the atmosphere quickly enough, the intercooler will continue to heat up until it is the same (or very close to the same) temperature as the air coming into it from the turbo. Thus, there will be no difference in temperature between the tube side (air going to engine) and air side (from the atmosphere, flowing over the intercooler as you drive); and the intercooler will not cool the air at all. When this happens, it is said that the intercooler is 'heat soaked'. It can be prevented by using a larger intercooler; increasing the amount of air moving over the intercooler (as in a FMIC versus a SMIC - although these are usually larger as well, which helps.); or by using an intercooler with a different cooling medium - such as a water intercooler.

Hope that helps.