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Tips for Hotter Street and Strip Performance - Part I

Tips for Hotter Street and Strip Performance - Part I


Part 1: Tips From An Engine Builder

Carl Wegner has been around performance since he graduated from high school n the ‘60s. He worked at John Schlieper’s legendary speed shop in Brookfield, Wis., building engines for Modifieds, USAC race cars and NHRA Top Fuel drag racing. In 1975, he moved to Markesan, Wis. and started Wegner Motorsports, which today builds engines for NASCAR stock cars. Wegner has also moved into street performance builds.

Wegner stresses an engine is basically an air pump. He told Hot Rod Hotline how this affects performance and gave us “tips you can take to the bank” for hotter street and strip performance. His tips make the air pump more efficient.

Your Engine As An Air Pump
Wegner said 80 percent of your engine’s power comes from cylinder head design. Pocket porting or high-tech machining can help you “use your heads” to better advantage. You can modify your heads or buy aftermarket performance heads to add an exhaust valve to each cylinder. This streamlines the flow of hot exhaust gases. You can also add performance exhaust systems with headers, fat tail pipes and flow-thru mufflers to reduce backpressure in your exhaust system.

An intercooler will cool the air entering your combustion chambers. Having cooler air in a cylinder make the air expand more during combustion. The compressed air from the cylinder passes through the intercooler, which acts in the manner of a radiator that cools the air before it goes into the cylinder.

Added hardware can give your engine a higher compression ratio so it will produce more power. You can avoid a tendency for the mixture in a higher-compression engine to “pre-ignite,” by using higher-octane fuel in your motor. Of course, there’s also no substitute for cubic inches. More cubes will result in the burning of more fuel each time your engine spins and ups its power. Boring and stroking the cylinder increases displacement. Adding cylinders will do the same.

Wegner said it’s important to ensure fuel delivery to each cylinder is precise and accurate. Carb tuning and balancing or better fuel injection system metering will produce the correct flow of fuel to each cylinder and improve performance and economy. Pumping air and fuel into a cylinder is the same as increasing the size/number of cylinders. Turbos and superchargers pressurize incoming air in such a manner that more air is forced into each cylinder.

“When your piston starts its down stroke it’s working against the air in the cylinder,” said Wegner. “You can lessen air resistance by getting more air out of the cylinder with a performance air cleaner, polished intake manifolds, better port gasket matching, ported heads, valve seat machining or an additional intake valve in each cylinder. The less air resistance, the more power you’ll have.”

Lightweight internal parts help an engine perform smoothly and efficiently, according to Wegner. Aluminum heads and blocks, featherweight pistons or titanium valves add power and use less energy when changing direction.

Carl Wegner’s Tips
Wegner’s street and strip performance tips involve using race-bred engine hardware. Wegner builds aluminum heads for Racing Head Service (part of Comp Cams). The RHS head for the GM LS V-8 gives a 50 hp advantage over stock heads. Port design and combustion chamber configuration make extra power. “We incorporate NASCAR mods into the production heads,” he explained.

With a $150,000 French made CNC machine, Wegner can produce special axis and vale seat steps without waiting two weeks to get new cutters made. “In five minutes we can draw new tool paths for the cutters and they will cut whatever we want,” he noted. “It’s the same machine all the F-1 teams use.”

The company makes six front dress assemblies for normally-aspirated LS engines and two for supercharged motors. The compact kits save weight and increase performance, while enhancing the looks of the engine pulleys and fans. Wegner’s billet valve covers feature good-looking, thin, weight-saving designs. One of the latest is a big-block cover with a receiver rail, instead of a bunch of perimeter bolts. Just two wing bolts on each side hold the covers down tightly.

LS motors are fuel injected and don’t have a distributor or manual fuel pump. Carl designed a front cover to install a Ford fuel pump and distributor in the GM engine. He modified a Chrysler 440 type water pump to fit the LS. He had it cast at Stewart Components in Escanaba, Mich., a division of EMP. Carl also developed, then sold to GM, a carbureted LS intake manifold design.

Wegner is a big believer in crank balancing, magna-fluxing, pin fitting, rod reconditioning, block/crank work and carb upgrades. Carl said that a stock LS motor with about 300 hp can be pushed up to 500 hp. “CNC the heads, put in a different piston and connecting rod assembly and add bigger valves,” he advised. “Remember the LS has all-aluminum block and head construction, so if they’re modified they weigh only 385 lbs—100 lbs. more than an old Chevy small-block. At 5.3 liters the displacement is 327 cid, so, it’s the 21st century 327 fuelie.”

Wegner likes cams and valve train components from Comp Cams and Manley. He’s big on Lunati and Callies cranks for the low- to medium-end engines and Winberg cranks for racing engines. MSD ignition is his favorite for distributor engines and he favors Comp Cam F.A.S.T. systems in engines requiring EFI controllers. As far as the Holley controller, Wegner advises, “It’s cost effective and a real nice compact package and it’s very good.”
Carl emphasized that 80 percent of an engine’s power comes from the cylinder head–cam-intake manifold combination, but said a shop can’t stop there. “The more you do on those, the more you have to ensure that the con rods. pistons and crank are up to supporting the other parts. One chases the other and hot rodders have to understand upping power will add costs for other upgrades.”

“Put away your flow meter, too,” Carl Wegner advises. “Basically, we don’t even flow a lot of heads anymore. We do most of our calculations through fluid dynamics and a cross sectional area. If a port has to have a certain taper, we do that in a CAD model and then CNC the part to fit that CAD model.”

Since moving into the street performance market niche, Carl realizes that he will need more than racing exposure to reach customers. “Up to now we’ve thrived on racing support and word of mouth advertising, but my son Casey is going to get more involved in going to car shows and trade shows.”

Carl Wegner feels that 80 percent of a car’s power comes from the cylinder head and valve train combination.

Carl Wegner has invested in special machinery that gives him advantages over other manufacturers of racing and performance cylinder heads.

This is a new front drive kit that Wegner Motorsports is in the final stages of developing for the LS engine aftermarket.

This Chrysler 440 type water pump has been modified to fit the General Motors LS. Wegner had it cast at Stewart Components in Escanaba, Mich.

Carl Wegmer developed, then sold to General Motors, a carbureted LS intake manifold design.

A modified General Motors LS V-8 has a lot of aluminum, so modified versions weigh only 385 lbs—100 lbs. more than an old Chevy small-block.