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Old 07-25-2022, 11:41 PM
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GTOKIDRH GTOKIDRH is offline
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Quote:
Originally Posted by amcmike View Post
Actually it is, and today's OEMs do.

Modern engines use much higher compression ratios, enabled by direct injection. The higher SCR increases efficiency even at part throttle, thus increasing fuel economy (in addition to increasing torque under wide open throttle). They can get away with these compression ratios due to the charge cooling as the fuel is injected directly into the combustion chamber (especially with multiple injection strategy at under medium loads and low-mid rpm). This then allows them to downsize the engine displacement (if desired) to further improve fuel economy. This is why OEMs use DI even on small economy cars, not just performance vehicles.
So correct me if I'm wrong. The LS engines before DI were mostly if not all in the 10+ CR range. I understand this was largely due to the use of aluminum as well as the heart shaped combustion chamber with a centrally positioned spark plug tip. Yes DI helps immensely.

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