Testing Facility and Protocols: All testing was completed at Sunset Racecraft of Lubbock, Texas. The dyno facility is equipped with a Dynamic Test Systems, Inc. (DTS) model 4000G engine dyno operated by Steve Figueroa, a School of Automotive Machinists graduate. All testing was done with the stock 2001 LS1 computer which was connected to the motor via a Superior Harness aftermarket wiring harness. VP 101 octane unleaded was utilized in the cell, fed to the engine via the shop's Aeromotive fuel pump and regulated to 58 psi. Dyno headers provided by Sunset were a set of Kooks 1.875-inch units that were modified with longer primaries and collectors (35-inch primaries and 8-inch collectors) to provide adequate clearance on the dyno. In order to ensure consistency in the test results, the various combinations were pulled after the engines had recorded 165 degrees on the test cell's DTS model S-1007M engine cooling system. The DTS specific cooling system provides for the cooling requirements of the engine, and no engine accessory belts were required since a Meziere electric water pump was utilized. Once the engine reached temp, the dyno operator took it to 3,800 rpm and then applied a dyno load. Once loaded, the engine was slowly brought up to 3,000 rpm and then pulled until the specified redline. Standardized SAE calculations were used to correct the horsepower and torque to industry standards. Reference temperatures for SAE calculations are 77 degrees Fahrenheit, and a barometric pressure of 29.23 inches of mercury. With an altitude of 3,200 feet above sea level and blistering humidity and temperatures on tap for the testing, it was reassuring to know that the DTS had had a recent calibration and was in top working order. Baseline: The test engine was a stock 2000 LS1 that formerly resided between the wheel wells of an F-body. With over 60,000 miles on the odometer, the test engine is just your run of the mill '00 LS1. The engine had stock 853 casting cylinder heads (12559853) and the 2000 camshaft that specs in at 202/210 duration at .050 with .496/.496 intake and exhaust lift (116 lobe separation angle). The intake and fuel injectors were updated to 2001 F-body specs that included an LS6 intake and 28-lb. fuel injectors. Aftermarket accessories were limited to a set of PRC Gold double valve springs, MSD 8.5 plug wires, NGK TR55 spark plugs and a Hypertech 160 degree thermostat. The factory springs were replaced due to the number of miles, but more importantly for the second test which would necessitate a valve spring that could handle lift exceeding .600. The factory computer program was left intact, but timing was locked at 26 degrees with LS1Edit to ensure that the computer didn't pull timing. Since there were not any knock sensor provisions provided, it was decided that VP 101 octane fuel would be used to keep the engine from potential detonation problems.
In the baseline dyno run, the stock LS1 surprised everyone by churning out a whopping 400.4 hp at 5,600 and 411.3 ft-lbs of torque at 4,800 rpm. Average power and torque (from 3,000-5,800 rpm) was 330.7 and 394.8, respectively. Reflecting back on the pull, Jason Mangum stated, "The baseline was about 10 percent higher than I anticipated since the average rear wheel horsepower of a 2000-02 F-body is normally in the 305-315 range. If we factor in drivetrain losses of 10 to 15 percent depending on transmission types, theoretically the factory SAE net crankshaft rating could range from 335 to 362 hp. The difference in what we found on the dyno versus our expectations must be attributed to the lower overall parasitic drag from the electric water pump and the lack of accessory drive belts. Another point to consider is that when GM eliminated the EGR on the 2001 F-body and went with the LS6 intake, their marketing suggested that the engine had better mid-range, even with the lower overall duration and lift of the '01-02 camshaft (197/202 at .050 and .467/.479 on a 116 LSA). The hotter '98-00 cam, in combination with the overall better flowing LS6 intake, probably picked up 10-15 horsepower by themselves, or roughly equivalent to what we see when a '98-00 car replaces the LS1 intake with an LS6. No matter how you analyze it, the stock LS1 is a potent engine with outstanding power and torque for the available head flow and camshaft." Magic Stick Time
Texas Speed has been designing custom camshafts for many years and fielded one of the country's fastest cam-only LS1 combinations in their '98 Z28 test car. The automatic equipped car with stock heads and a Magic Stick 3 camshaft went a best of 10.51 at 125 mph. From the beginning, the Magic Stick cam was designed to be the largest camshaft a stock cubic inch LS1 (346 ci) could run safely without having to cut valve reliefs in the pistons. Designed as a max effort street cam, it's intended for naturally aspirated or nitrous applications. Loud, rowdy and proud, the latest revision to the Magic Stick line is the MS4 (part number 25-MS4, retail price $399.99). Now on the fourth revision to the Magic Stick line of cams, the Magic Stick 4 measures in at 239/242 duration at .050 with .649 intake and .609 exhaust lift. Built on a 111 LSA (optional 112 LSA for smoother idle) and 109.5 intake center line the MS4 provides a lumpy idle that settles in between 850-900 rpm. The latest revision features an even more aggressive intake ramp, reduced lobe separation (MS3 was 113 LSA) and built in advance to bring the power band in earlier. Custom tuning is of course a necessity but with a power band of 2,300-6,800 rpm, only the die-hards will be daily driving this stick.
As previously discussed, a valvespring capable of handling high lifts was a requirement so PRC's Double Gold springs were used (part number 199-spkit, retail $269.99). Included in the package are steel spring seats, titanium retainers and viton valve seals. Capable of .660 lifts, this is a stout spring. Complementing the springs was a set of Texas Speed & Performance hardened chromemoly pushrods in the standard 7.400-inch length (PN 25-7400, retail price $109.99). Although the stock pushrods could have been used, the addition of a stronger pushrod would ensure that the valvetrain remained stable, without any unwanted harmonics disturbing the valvesprings due to the notorious flex exhibited by the stock pushrods in above stock valve lift events.
After a quick cam swap, the little 10:1 compression 346 was warmed up and unleashed. With just a cam swap, the engine responded with peak horsepower of 482.3 at 6,400 rpm, for a staggering 82hp gain over the stock cam. Torque also increased to a peak of 439.1 at 5,100 rpm for a gain of 28. According to Jason Mangum, "By increasing the initial advance and incorporating real quick intake ramps, the cam starts exceeding the stock power levels right at 3,000 rpm. Although the peak horsepower was at 6,400 rpm, the cam will pull to 7,000 rpm with very little drop-off." In addition to the peak gains, average power and torque (from 3,000-6,500 rpm) was 370.9 and 407.3, respectively. Average horsepower increased by 40, while peak torque clocked 12 ft-lbs. From a tuning perspective, Jason added 2 percent fuel under 3,000 rpm and 1 percent above 5,800 rpm via the PE tables on LS1Edit.