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Old 09-12-2019, 01:44 AM   #11 (permalink)
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spyder2 - '00 Toyota MR2 Spyder
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Originally Posted by Ecky View Post
I found something quite interesting when poking about with Honda's K series. Turns out the engine in cars like the older Type R, TSX, Civic Si, don't actually go rich even at WOT. That's true of most stock engine maps. Honda chose instead to pull timing to prevent knock. Now, admittedly this also has a fuel economy impact, since your peak cylinder pressure is farther from optimal crank angle.
Correct, many older engines did not run rich at WOT until about 3500-4000rpm. Stepping hard on the gas is less detrimental in those cases.

Everything newer though does go rich. All of the Toyota [A/N/Z/G/U]R engines do for example.

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