Heat soak

[roy2535]

Hey guys, kind of a noob on the subject of heat soak

Could anyone explain to me what would happen when 'heat soak' is present? I understand that it happens when the intake air temperature gets too hot, resulting in reduced power produced by the engine. I'm just wondering what is the reason for that? Is it less fuel being injected into the cylinders or something else?

I am currently running APR stage 1 on my gti, at what intake temp will hear soak starts to be a factor? Typically I'm seeing intake temp of around 60C (~140F).

In thinking whether I should get an upgraded intercooler or wmi to mitigate the issue. Thanks!

 

[drrck]

High intake temps cause the engine to reduce boost, pull (retard) timing, and lastly enrich the mixture (inject more fuel). All of these are done to prevent per-detonation (knock) which is a condition where the fuel combusts under pressure sooner than optimal. This creates dangerous spikes in pressure.

Reducing boost helps decrease the temperature, pulling timing (injecting the fuel later) helps to prevent knock, and enriching the mixture adds more fuel which makes for a cooler burn due to the evaporative effect of fuel atomization.

WMI and intercoolers both help decrease the charge air (intake air) temperature and this will help prevent intervention by the ECU to protect itself. 60C is getting somewhat hot, but not terrible.