Dan Timm, Wegner Motorsports
"Developing the NASCAR LS1 Spec Engine and LS in NASCAR of Tomorrow"
Long-time employee and (now) General Manager of Wegner Motorsports, Dan Timm is in the exciting position of introducing LS1s to circle track racing. His work for racers in a local series peaked the interest of NASCAR, which is now in the process of adopting his Spec engine program for several series.
The Camping World East and West racing series will now sport Wegner Spec LS2 engines, which Dan says allows competitors to save money and be competitive. The Wegner program stuffs an LS2 block with a Lunati crank and rods, JE pistons, and Dana rings. Stock rocker arms with COMP bearings and trunion command GMPP CNC-ported 243 casting heads, which are "mild but maximized." Though the flow numbers aren't amazing, Dan says the dyno proves that GM really did their homework. An Edelbrock intake and carburetor, a distributor with special front cover, and EMP Stewart water pump are also part of the package along with a 3-stage dry sump oiling system with 100-micron or higher filters.
Dan said there have been many challenges along the way, in instituting this program such as parts availability, logistics, education and providing information. It is difficult to convert many old school racers and crews that have come to know and love the Gen I SBC so much. Their lack of familiarity, however, may eventually give way to the many advantages that the Gen III/IV allows. According to Dan, one thing the racers have come to find out is that the aluminum block is very unforgiving with overheating, whereas their old iron blocks would keep ticking. The future looks bright for the program as Wegner is looking into possibly employing a similar program in a truck or cup racing series. The 6.2L Gen IVs, he says, have great potential for 410 dirt track cars making around 678 horsepower.
Kenny Duttweiler, Duttweiler Performance
"Advanced LSx Forced Induction System Design, Building and Tuning"
Kenny Duttweiler has one of the best names in the business when it comes to building engines, and he has been on the cutting edge of late model EFI GMs since opening Duttweiler Performance in 1984. His Grand National is legendary for being the first to hit single digits and eventually 6s. Both as an engine builder and a racer with 45 years of experience, Kenny has achieved many more accolades--too many to list here. His most recent work developing LS engine packages and testing for MagnaCharger landed him a spot on the podium.
Kenny said his latest work with the new High Helix Magnuson blowers has found the 1.9L can easily be pushed to its max with a serpentine pulley, meanwhile the 2.3L blower requires a cog drive. The 1.9L or 1900cc blower will make 800 hp (80 pounds per minute). The 2.3L or 2300 will make upwards of 1,000 hp (100 pounds per minute). Duttweiler has managed to spin the blower to 25-28,000 rpm, which is past Eaton's durability standard. Kenny says to keep in mind boost is gauge pressure, what's left after it goes through the cycle, not what the device is capable of producing. The old 3-lobe 90-degree rotor has been replaced by 4-lobes and a 160-degree twist, which is quieter (probably how the CTS-V and ZR1 meet stringent noise standards). Runner length on these blowers appears to make no difference as experiments have proven. The gasket type is of a high quality, providing a good seal and temperature protection. Overall he said the MagnaChargers are a good air delivery device that packages well, though it can't compete in a drag race with a turbo.
Building a motor to accommodate such boost has also revealed many insights into the Gen III/IV platform, Kenny said. For starters, the LS2 block requires honing up to 4.005-inches for a proper cylinder (4.02-inch max). Cathedral-port heads produce more torque, but are flow-limited to about 340-350 cfm. Rectangular ports flow much better, especially CNC-ported L92/LS3. Testing has revealed that the use of various coatings only yields about a 6-8hp gain. Meanwhile aftermarket oil pans make no difference in horsepower, Kenny speculated it's most likely because of the deep-skirted block, making it limited by windage. The factory head gaskets, Duttweiler says, prove reliable to 700 hp, and Fel-Pro 4-layer gaskets are near bulletproof (around 2,000 hp capable) with studs. Copper and O-ring gaskets are suitable for 2200-2400 hp. Kenny says it is imperative to stay up with the latest info on fastener torque, though he tends to over-torque. The GM coils are great (up to 1400-1500 hp) with a closer plug gap (.020). The Gen III PCM Kenny believes is the best to use, as it's less complex, and the software is the best. Utilizing a MAF is most desirable whenever possible, a 100mm MAF will read over 670 hp. The throttle body has been the biggest issue (as much as a 40 hp gain possible), in terms of intake restriction, though a larger MAF can add up to 34hp.