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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
long story short: After swapping my TPI manifold to a edelbrock pro flo 4 xt tunnel ram my rpm range increased tremendously.
The installed SLP cam 51002 (206/212 @.050 112 LSA) is working good but doesnt match the rest of the setup at higher rpms above 5000 anymore.
So I looked some manufacturers up and asked them for cam advice. All of them suggest something in the neighbourhood of 215-220 @.050 intake duration and a 110 LSA for my refreshed 305.
Howards suggests the 183215-10 and related to the values, I like it very much!
But what I never thought about is valve overlap since the very mild cam installed doesnt have overlap.
The howards almost dont either, just 1° overlap. But it's still a step wilder.
So I asked myself: What effect does valve overlap have on efficiency/fuel economy?
Sure it can increase performance because through overlap and a good scavenging the exhaust of the cylinder can be evacuated better and the intake air drawn better in it, something like that...
But what is with efficiency/ fuel economy? Does it hurt at all or much?
