The 5.3-liter GM Gen III engine came from humble beginnings as an easy to find engine at any given junkyard (due to its widespread use in GM trucks) as an alternative to an LS1, and now it’s becoming an engine prefer instead of the LSs, especially when it comes to boost. These engines seem to love to be force fed! However, it is important to considered other modifications – like camshafts, cylinder heads, and air intakes when you’re going to be boosting your 5.3L. So how do you determine the best combination for your engine? Let’s examine the factors.
RHS, FAST, and COMP Cams supplied the parts and insight into the modifications done to this engine, also offering how it’s double as important to have a good combo over naturally aspirated engines. Obviously, the areas mentioned prior are what make the biggest power gains on a naturally aspirated engine. The right components on an engine that hasn’t (yet) been touched by boost can offer an impressive 100 horsepower gain – meaning a 300 horsepower engine that was given a bump up to 400 horsepower picks up 33-percent more horsepower, so let’s throw some boost on that and see what happens.
When you add boost to an engine, a lot of cool stuff starts to happen. When you apply even as much as 14 pounds of boost to a 300 horsepower engine, you could easily double the horsepower, now take into account the engine was already modified to 400 horsepower – so double the horsepower now means 800 horsepower, instead of 600. This is why it’s so important to build a good base engine to compliment turbocharged or supercharged engines.
Of course, this wouldn’t be a proper Speed Secrets segment without some dyno time to prove the theory, and just that happens. With no other modifications than a turbo, the engine is dynoing right over 608 horsepower, while the modified engine doubled from the 500 horsepower range to over 1,000 horsepower!
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