Build a Supercharged LS Engine With Massive Torque and Horsepower
Want to be able to go into a monster rolling burnout at 30 mph? Then this package should get your attention. With a Harrop TVS2650 screw-blown supercharger up top, this LS put up 920.9 hp and ridiculous amounts of torque all through the rpm range with just 388 ci.
We know. We know. Horsepower is the sexy member of the family. Horsepower gets all the attention and is all anyone wants to talk about at parties. But hear us out: Torque is where it’s at. Few things in life are more fun than a great car with gobs of torque on demand every time you touch the throttle. Torque is what mashes you back in the seat. Torque is what makes the car squat on acceleration. Torque is what allows that most magical thing known as “burnouts.”
We’re looking for big power, but since this is a forced induction build the cam doesn’t need to be huge. The guys at Prestige Motorsports got together with the tech staff at Comp Cams for this grind. They came up with a solid roller with 250 and 262 degrees of duration for the intakes and exhausts at 0.050 tappet lift. To keep from blowing all that boost out the exhaust ports, lobe separation is widened to 113 degrees with a 108 intake centerline.
And that’s the goal for this build. We’re at the shops of Prestige Motorsports in Concord, North Carolina, where they are building a competition-level LS for a drifter. Top-level drifting is a pretty demanding—and unique—sport. But no matter if you are a drifter yourself, are a grudge racer, or just a street brawler, an engine that produces mountains of torque all the way through the rpm band is tough to beat.
Prestige plans to spin this engine up pretty high in the rpm range, so rpm will be limited to the stock 3.622-inch stroke. But this forged crankshaft from Manley can shrug off absolute tons of power. The mains journals are fitted into a set of coated King XP main bearings.
Drifters have run every form of engine imaginable, and in just about every configuration you can think of. But the singular thing they require is instant throttle response so that they can break the tires loose exactly when they need to and then keep turning tire rubber into glorious smoke for as long as possible. To maximize instant torque that starts right off idle, the mad scientists at Prestige decided to go with a big screw blower—complete with a built-in intercooler—on top of the LS. A screw blower is more efficient than a roots-style blower when it comes to moving air efficiently at high rpm. That’s mainly because a screw blower actually compresses the air inside the case, so it is under greater pressure when it leaves the blower housing and begins its path down the intake ports in the cylinder heads. A roots blower doesn’t compress the air as it moves it through the blower case and into the engine.
The block is a Dart LS Next cast-iron unit. These are unique because they utilize beefy four-bolt main caps, but to reduce windage there are no cross-bolts like you may be used to seeing in LS blocks.
But beyond that, the guys at Prestige made some other critical considerations for both longevity and power production with this build that are really smart, some of which you may want to take advantage of on your next project.
The connecting rods are also from Manley. These 6.125-inch long rods (center to center) have an H-beam design and utilize ultrahigh-strength ARP 2000 rod bolts.
And that’s especially true once you see the results. These days turbos are all the rage when it comes to power-adders. And that’s because they have many great advantages—like they use the exhaust to spin up the compressor so there are practically no horsepower demands on the engine and they offer better flexibility when it comes to packaging the systems in cars with low hoods. But a screw-type supercharger is hard to beat when it comes to seat-of-the-pants feel. Because the blower is mechanically connected to the crankshaft and always mirrors engine speed—plus, it is positioned so close to the intake ports on the cylinder heads—the lag from mashing the throttle pedal to being pressed back into your seat is as quick as you are going to be able to find. And don’t forget about the tire-shredding torque we mentioned earlier.
Mated to the connecting rods are a set of piston forgings from DSS Racing. They are sized at 4.125 inches in diameter and have a 10cc dish to help dial in the compression ratio.
This combo with a well-built LS and a Harrop screw-type supercharger up top pegs the fun-meter on 10. Just check out these photos of the build as well as the results on the dyno sheet and you’ll see what we mean.
ACP
Here’s another look at the DSS pistons now in the block. At TDC the pistons have a zero-deck (level with the top of the block). This maximizes the squish area, and the 10cc dish helps concentrate the air/fuel mixture in the center of the combustion chamber—and near the spark plug—for the best possible combustion efficiency.Drifters are on and off the throttle a ton during a run, plus tires hooking up and then breaking loose can send shockwaves all the way up the driveline. So, Prestige went with a high-strength double-roll timing chain for improved durability.That double-roll timing chain did cause one issue. It contacted the stock front cover right at this boss. But that wasn’t an issue. Five minutes with the grinder and we had the clearance we needed.Although they are constantly sliding the rear end, drifters also pull some incredible g’s throughout the course. So, to maintain good oil control no matter how high the side-loading on the car, Prestige is using a dry-sump oiling system. At just 4 inches deep, this Moroso oil pan not only has three built-in pickups for scavenging, it’s also quite shallow (since the oil is pulled out of the pan immediately and held in an external tank) so the engine can be mounted as low as possible to improve the car’s center of gravity.The aluminum cylinder heads are Brodix’s BR series that have been CNC-machined to spec in-house at Prestige Motorsports. They have been optimized for performance with an LS7-style valve arrangement and ports, although you can still bolt up LS3 intakes and exhaust manifolds. Prestige built them out with 2.165-diameter titanium intake valves, while the 1.590 exhausts are cut from Inconel.Here’s a better look at the 69cc, CNC-cut combustion chambers. Final compression ratio will be 9.85:1.Old-school thinking said that port design on boosted engines didn’t matter because the blower will just push the air on through bad ports. But in competition engines it has been proven that better-flowing ports reduce intake temps, make the blower setup more efficient, and just make more power. For example, with these Prestige-designed 275cc intake ports, the finished engine will show less boost pressure compared to most other cylinder heads. That’s because boost is a measure of resistance (how much air the blower is moving versus how much the engine can ingest) and the engine will make more power even though the boost gauge shows a lower number.The valvesprings are from Manley and have been installed with 270 pounds of pressure on the seat and 750 open. The retainers are also from Manley and constructed from lightweight titanium to help maintain valve control near redline. To protect the titanium intake valves, stainless steel lash caps have been installed. That’s why they look so much thicker in diameter than the exhausts.The shaft-mount rocker arm system is a set of aluminum Jesel rockers from their Sportsman series and keeps the stock 1.7:1 ratio. Gross valve lift will be 0.673 for the intakes and 0.682 for the exhausts.This is the lower plenum for the Harrop supercharger. In this shot you can see the integrated water-to-air intercooler. Most systems like this place the intercooler directly underneath the blower unit so that the hot air exiting the blower flows straight down through the intercooler then enters a shallow plenum underneath where it can move toward the intake ports. This configuration allows the entire setup to be a little bit shorter because the air flows horizontally through the two intercooler sections and exits right at the beginning of the intake runners in the cylinder heads.Harrop uses these sweet billet aluminum pieces to mount the hoses for bringing the water into and back out of both intercooler sections. The 90-degree elbows help keep the overall packaging nice and compact.Here, you can see the curved lobes of the screw blower design.Because this engine uses a dry-sump oiling system, the Moroso three-stage oil pump is driven off a belt. Oil will be pulled out of the pan the moment it enters and is pumped into an external tank. This not only helps reduce power-robbing windage, but it also removes the chances of a drop in oil pressure if the pickup becomes uncovered during extended high-G turns.The fuel injectors are from Fuel Injector Clinic and rated at 1,000 cc per hour.Prestige worked with Moroso to have these billet aluminum valve covers made complete with valvespring oilers. A pressure line is plumbed to each valve cover and a cooling stream of oil is sprayed onto each spring to help improve durability.The completed front drive setup includes provisions for the alternator and external oil pump. The throttle body is a big 102mm unit from Holley.It is important to note that this is not a pump-gas engine in its current form. But if you want to do that all you will need to do is increase the upper pulley size to knock down the boost a bit. Anyhow, burning C16 race fuel (117 octane), which is the dyno standard at Prestige and probably a higher octane than absolutely necessary, we saw peaks of 920.9 hp all the way up at 7,400 rpm and 704.6 lb-ft of torque at 4,300. Best of all, the torque never dipped below an astounding 650 lb-ft of torque all the way to 7,500 rpm!(Dyno Chart)
