Speed Secrets: What’s So Great About the FAST LSXR Intake?

When GM designed the LS1 engine, they didn’t give it an intake to do it justice. Thankfully, FAST came up with a solution. Richard Holdener explains the magic behind the LSXR intake in this episode of Speed Secrets.

Of all the intake manifolds GM has produced over the years, the LS1, the beginning of arguably the best GM engine family ever made, was the least powerful. With all the success of the LS engine, the intakes did get better. The LS6 and LS2 intakes were an incredible improvement, and who could forget the truck manifolds. By far though, the best GM produced manifold was the one that appeared on the Trailblazer SS, but with compartment fitment issues for a lot of cars equipped with LS engines, the manifold left still a lot to be desired. 

Lucky for all the LS guys out there, Fast introduced their LSXR intake manifold as the go-to LS performance intake manifold. But how much better is the Fast than the best of the GM produced intakes? Richard Holdener of Speed Secrets, together with the guys at Fast, set out to find out. 

To test how GMs Trailblazer SS manifold compares to the Fast intake manifold, Richard assembled an iron block 6.0L LS with forged internals, aftermarket high flow cylinder heads, and a powerful Comp camshaft – 54-469-11 – with a .617/.624 lift, 231/247 duration, and a 113 LSA. Using this combination allowed the team to throw a maximum amount of power at each one of the intakes to see what each one had to offer.

As a baseline, the team first dyno tested the 6.0L with a truck manifold. The GM truck intake allowed the modified 6.0L to make an impressive 549 HP @ 6,900 RPM and 481 Lb-Ft of torque @ 5,000 RPM. After swapping the truck version for the Trailblazer SS intake, the LS engine made even more power at 563 HP @ 6,900 RPM and 497 Ft-Lb of torque @ 5,300 RPM. Finally, with the Fast LSXR intake installed, the engine nearly broke 600 HP. The Fast LSXR intake produced 591 HP @ 6,900 RPM and 505 Lb-Ft of torque @ 5,700 RPM.

While the Fast LSXR intake manifold may be more expensive than finding a used Trailblazer SS or GM truck intake, if you are trying to get the most performance from your LS engine, neither of these options come close to the Fast intake. With over 40 more HP than the early GM truck manifold and almost 30 more HP than the Trailblazer SS intake, the Fast LSXR intake manifold can help you find all the horsepower you are looking for.