LS1 Heads and Cam Test - LS1 Camshaft Roundup, Part 2
We jump head first into another round of stock-block LS1 engine testing
From the July, 2011 issue of GM High-Tech Performance
By Justin Cesler
Photography by The Author
Welcome to the second iteration of our LS1 Camshaft Roundup! If you have been following along since Round 1, you will be happy to know that we have made even more horsepower this time around and upped the anti with a brand-new set of aftermarket cylinder heads. If you are just joining us, let’s get you up to speed. With the help of our friends at RaceKrafters in Lancaster, Pennsylvania, we have set out to test a plethora of camshaft offerings from around the globe to see how they react on an otherwise stock LS1 engine. Now, this isn’t one of those drivability tests or one of those “let’s find out that everyone wins” events—the Camshaft Roundup is all about making huge numbers, drivability be damned!
For round two, we made the call to Futral Motorsports and Patriot Performance to see if they were interested in testing. I am not sure I had even five words out of my mouth before hearing “Yes!” from both parties, and the camshafts and heads shipped to RaceKrafters just moments later. For those of you wondering, yes, these are the new Patriot Predator cylinder heads, which are built from an entirely new aftermarket casting and formulated to make some serious power. Interested in seeing how each piece of the puzzle did? Read on and make sure you let us know if you have any questions, concerns, or ideas!
Testing Procedure and Camshaft Guidelines
Whether you have been following our LS1 camshaft series or not, it is important to review our testing procedure and guidelines before beginning to interpret the data. As with any test, it is imperative to maintain strict guidelines to ensure valid results. Below, you will find our procedures for testing, along with our camshaft specification guidelines. While the former was very specific, the latter was left wide open, allowing manufacturers and builders to spec camshafts to their liking.
&bull Install camshaft and related valvetrain components
&bull Degree the camshaft, install to correct specs, +/- .5-degree
&bull Establish a solid idle, check base timing, set 27-degrees of total timing
&bull Oil temperature – 130-degrees F, +/- 10
&bull Water temperature – 155-degrees F, +/- 10
&bull Power pull, maintain solid AFR and timing, validate data
&bull Two additional power pulls, extract best run and record
&bull Rinse and repeat, allowing ample time for cool down
&bull If it fits in a stock LS1, it’s in the test
&bull Must be an off the shelf grind, no custom camshafts
&bull No fly cutting, no head gasket spacing, no tricks
&bull Comp Cams springs, retainers, pushrods and timing set
As previously discussed, our baseline numbers come from a stock ’98 LS1 short-block. Prior to any testing, Racekrafters replaced the stock ’98 heads with a fresh set of 241-casting LS1 units and swapped intake manifolds in favor of the newer LS6 with a matching throttle body. On the engine dyno, Racekrafters bolted up a set of 1.75-inch long-tube headers, which flow into a pair of 2.5-inch pipes and matching 2.5-inch Flowmaster mufflers to replicate real world results and, secondarily, to keep our ears from bleeding after days of testing! To help maintain consistent coolant temps, Racekrafters relies on a Meziere electric waterpump and keeps it running in between pulls to help prevent heat-soak. In that form, with the stock camshaft and cylinder heads, the old LS1 laid down some impressive numbers with 418 hp on tap at 6,000 rpm and 422 lb-ft of torque. Not shown on the baseline graph is the addition of a FAST 102 LSX-R intake manifold, which we installed during our first test session. It should be noted that all of the following tests were completed using the FAST 102 LSX-R intake manifold and not the stock LS6.
|Average TQ:||405.6||3000-4500 rpm||0.0|
238/242-duration, .599/.612-inch lift, 112 LSA
The first camshaft in our second round of testing came to us from Allan Futral of Futral Motorsports. If you are a loyal GMHTP reader, you should already be familiar with Allan, but for those of you hearing his name for the first time, know this: Allan is a master camshaft supplier for LS engines and has spent his time building killer all-motor and forced induction builds, all based around his custom camshafts. Up first, Allan sent us a 238/242-duration camshaft with .599/.612-inches of lift on a 112 LSA, which Allan calls the FMS-F16 (PN FMS-F16-112). Billed as an “aggressive profile with a 3600-7200 rpm range, rough idle and violent mid-range,” the F16 represents everything that this test is about—raw horsepower!
In that department, the F16 didn’t disappoint, ringing in with an incredible 513.4 hp at 6,700 rpm. 513.4 hp is a huge number and represents a gain of 95.4 hp from our baseline engine testing. Compared to the stock camshaft, which made peak power (418 hp) at 6,000 rpm, the F16 was already making 494.7, a gain of 76.7 hp at the same rpm. In fact, the F16 made 417.6 hp at 5,000 rpm, further proving how violent the mid-range power actually was. Torque, as you would imagine, was up with the F16 as well, with the LS1 laying down 442.2 lb-ft at 4,800 rpm, a gain of 20.2 lb-ft of torque. Across the lower rpm range, from 3000-4500 the F16 was up 1.7 lb-ft, which was good considering that the camshaft was built to operate from 3,600 rpm on up.
|Average TQ:||407.3||3000-4500 rpm||+1.7|
238/242-duration, .599/.612-inch lift, 112 LSA + Patriot Predator 215cc heads
Impressed by the F16 camshaft, we turned our attention to the stock 241-casting GM cylinder heads and decided it was finally time to see what the LS1 could do with an aftermarket casting. Enter Patriot Performance and the company’s brand-new, and longtime coming, Patriot Predator LS1 cylinder heads. Designed in-house from a clean slate, the Predators represent everything Patriot has learned about LS1 cylinder heads over the years, combined with the company’s knack to keep performance affordable. With 2.02-inch intake valves and 1.600-inch exhaust valves, the Predators ship from Patriot ready to bolt on to any LS1 and can be used on a variety of applications. On paper, the stats for the Predator heads looked great, but as always, Bob Wise and I decided to tear them down before doing any testing, to verify that everything in the new casting was as it should be. Of course, everything was spot on, with 64cc combustion chambers, 2.02/1.60-inch valves and a great mid-range 214cc intake runner matched with an 87cc exhaust port. On RaceKrafters’ flow bench (with no pipe), we recorded 303 cfm at .600-lift, with 308 at .650, 312 at .700 and an amazing 314 at .750-inch lift. Not that we planned on seeing that much lift, but it is nice to know that the Predator heads can flow that well without backing up in the upper lift area. On the exhaust side, the flow characteristics were similar, with 210 cfm at .600-inch lift, 215 at .650, 218 at .700 and 221 cfm at .750-inch lift, again proof that Patriot did its homework on the port design.
Bolted to the engine, the gains were just as impressive. Paired with the F16 camshaft, the Patriot Predators laid down 534.2 hp at 6,600 rpm and 464.3 lb-ft of torque. To make sense of those numbers, that’s a gain of 116.2 hp and 42.3 lb-ft over the stock LS1 and a gain of 20.8 hp over the 241-casting cylinder heads alone. Average torque from 3,000-4500 rpm was up 17 lb-ft, coming in at 422.6 lb-ft compared to the stock 405.6 lb-ft. Not only did the heads make more overall power, but they hit peak horsepower 100 rpm sooner (6,600) and peak torque 200 rpm sooner (4,600). For a new casting, right out of the box, the Patriot Predators really did impress, with both great flow numbers and real world performance.
|Valve Lift||Intake CFM||Exhaust CFM|
|Patriot Predator: 2.02/1.60 intake and exhaust valves, 64cc|
combustion chamber, 214cc intake runner, 87cc exhaust port
|Average TQ:||422.6||3000-4500 rpm||+17|
242/245-duration, .646/.637-inch lift, 111 LSA + Patriot Predator 215cc heads
With our new found horsepower and torque, we were anxious to see what adding more duration and lift would do to overall power and performance, although we were fairly certain that any potential gains would be small, given our previous testing. Allan Futral sent us a monster for testing, a camshaft so big that he calls it the Godzilla Jr (PN FMS-Godzilla Jr). With 242/245-degrees of duration at .050, .646/.637-inches of lift and a 111-degree lobe separation angle, the Godzilla Jr. is certainly large and, according to Allan, is built for “a 4,000-7,500 rpm range.” As such, average torque was down slightly from the smaller camshaft but, surprisingly, was still up over 10 lb-ft across the 3,000-4,500 rpm range, with an average of 415.8 lb-ft of torque. Peak power, as you probably guessed, was impressive at 540.9 hp, the highest in our test by a large margin. Peak torque was down when compared to the F16, but still up over 40 lb-ft when compared to the stock LS1. Naturally, with such a beast, the entire powerband was shifted upwards with this combination, with peak power coming in at 6,800 rpm and peak torque around 5,300 rpm. Needless to say, if you dare to put this combination in a car, you’re going to need a huge (4,500-plus) stall converter and a steep ring-and-pinion to keep you in the powerband. That said, it would be one heck of a ride and could easily run with some of the best heads/cam combinations in the country.
|Average TQ:||415.8||3000-4500 rpm||+10.2|