Quote:
Originally Posted by IamIan
What OEM Carb based ICE achieves higher AFRs than the 25.8 : 1 that some OEM EFI ICEs have been tested to be able to achieve?
What I've read EFI systems have superior higher LB AFR benefits potential to Carb based systems... thus ... from what I've read ... it is the opposite of what you are claiming... and it is Carb systems that suffer with lower AFRs.
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The main reason we have EFI is to tune exactly to spark. The point where carbs become more efficient is
above 26-27:1 AFR. Around 28-30:1, so combustion temps are just below the melting point of steel (think upward to 2500 deg F combustion temps), which is what adiabatic ceramic engine's are all about. And you're knowledgeable enough to know that this can't happen on a traditional ICE. When we're talking about an ignition based ICE yes, but not when there is no ignition.
Preheat the fuel to 450+ degrees before entering the intake manifold, (autoignition temp of gas is 475 deg F+), the pressure of the cylinders works the combustion. It's walking a fine line against extreme backfires outside the combustion chamber
but it's been done, and it's not at all an OEM setup. I guess I wasn't clear that the idea couldn't be achieved on any old stock carb. Or any old engine for that matter. It'd be a very tricky process, and it can't be done with EFI. Most FI systems run at least 30psi (most stock ones 45-65), where carb can run less than 5psi. Much easier to 'preheat' a lower pressure fuel.
...an ignition is needed to get the whole system up to operating temps, but after that its not needed