Summary

00:00 - Oxrab's asked, are there alternatives to a rich mixture in terms of keeping down the temps, so combustion chamber temps such as water injection is what he's suggested here? So yeah absolutely, water injection is a really good solution.
00:12 If you are stuck with a low quality pump gas which will be prone to detonation then water injection does a really good job of cooling our combustion charge temperature and the reason that that happens is due to the latent heat of evaporation of water.
00:28 Now what that simply means in layman's terms is that when we inject the water and it goes into the combustion chamber, it goes through a phase change, it turns from liquid into vapour and in order to make that phase change from liquid to vapour, it absorbs energy in the form of heat from the combustion chamber so that's why it reduces our combustion charge temperature.
00:50 So water injection's one option.
00:51 The other way of getting around this is to run on a different type of fuel.
00:57 Now there's two advantages here.
00:59 With E85 for example, we get the benefit of the higher octane that E85 has compared to pump gas so it's going to be less sensitive to knock or less prone to knock even for the same combustion chamber temperature, combustion charge temperature.
01:15 However the other benefit of alcohol based fuels is again just like water, higher latent heat of evaporation compared to pump gasoline so it absorbs that energy in the form of heat so it cools the combustion charge temperature.
01:28 Methanol is another really good example of this and if anyone's actually seen a methanol car running, often at idle you'll actually get condensation forming on the inlet runners because of the cooling effect of that fuel.
01:41 Another reason why we see a lot of methanol drag cars don't actually run an intercooler, they're actually using the fuel essentially for cooling the combustion charge temperature to a point where the intercooler is sometimes not necessary.
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