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Testing Different Cams for Boost on a Supercharged 4.8L LR4 Engine (Video)

In today’s video, veteran engine builder Richard Holdener is testing three different camshafts on a supercharged 4.8L LMR engine to see how each of them impact boost and power.

The engine, with the a Whipple supercharger perched up top, is built from the factory block, factory crank, Gen. III LS connecting rods, JE Pistons (with 7cc dome volume and valve reliefs), Trick Flow cylinder heads, 83-pound fuel injectors, and a Holley HP EFI management system.

The three camshafts Holdener tests are:

  1. A factory LS9 cam – .558/.558 lift, 211/230-degree duration, and 122.5-degree lobe separation angle (LSA)
  2. Lil John’s Motor Sports (LJMS) blower cam – .610/.596, 223/238 lift, 120 LSA
  3. Crane Cams naturally aspirated (NA) cam – .590/.590, 224/232 lift, 115 LSA

Holdener said the Crane NA cam has always served him well, so he wanted to see what would happen in an engine with a blower.

All three cams were run with the same air-fuel ratio, the same timing, and the same pulley ratio.

Holdener invites the audience to weigh on on whether they would prefer to adjust the pulley so that boost is the same, or to keep the pulleys the same to see what happens to the boost.

Again, in this video, Holdener chose to keep the pulleys the same because was testing specifically for how each cam affected the boost and horsepower levels of the engine.

Check it out.

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