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Speed Secrets: LSXR vs. Stock Truck Intake Dyno Test! Which Makes More Power?

Working with the experts at FAST, it’s time to test the factory 5.3-liter intake manifold against the LSXR intake manifold. If this goes like any of the prior testing, the FAST manifold is going to be a tough one to beat. This is even truer with heavily modified engines, but how well will it work on a milder 5.3-liter engine? That’s what the Speed Secrets crew breaks down in this video.

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Most engine dyno tests are setup through planning and design, but this truck intake manifold versus LSXR intake manifold test actually happened by accident. The engine came from Strictly Performance for the test, it had a slightly built bottom end and ported heads. Prior to the tests, a healthy COMP Cams camshaft was installed, so now it has heads and cam, but needs an intake to meet the performance trifecta.

With the engine on the dyno with the factory intake, the modified 5.3-liter engine made 476-horsepower and 424 lbs-ft of torque – not bad! Now it’s time to install the FAST LSXR to see how it does, it also got a matching 102mm throttle body, but as you’ll recall from a prior test, the throttle bottle is only as good as the intake being used.

The results are in, and the LSXR comes through once again. With the FAST intake, the power increases to 501-horsepower and 432 lbs-ft of torque, so the little 5.3-liter test engine exceed 500-horsepower without forced induction or nitrous!

Get more insider information on building an engine here:

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