Quote:
Originally Posted by 435gc
Great post.
Can you explain a bit on why/how timing drops effect EGTs and why increased EGT causes higher boost?
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EGTs and timing, simple summary:
Basically, when you pull timing, you leave less time for the combustion to take place in the cylinder where you want it.
The impact of higher EGTs on boost is easier to think of in terms of energy... higher temperature exhaust has more energy. The turbo takes the energy from the exhaust gases and uses it to spool the turbo. If the exhaust gases are higher temperature and have more energy, the turbo has more energy 'available' in the exhaust gases to spool. This same energy concept is applied all over the place - think about lean spool (lean AFR increases EGTs), 2step LC (which pulls timing generally), and even people who heat wrap manifolds to keep all that heat in (also under hood heat management aspect to this, but the idea of keeping the energy in the manifold and exhaust gases is the same).