Better Boost

We Test Whipple’s New 3.0L Supercharger to See if it Can Make Power on a Big-Inch LS Build

By Jeff Huneycutt – Photography by the Author

Whipple superchargers have been a popular option when it comes to making horsepower for years because their screw-blower designs are proven to make great power in a compact package. A twin-screw supercharger has an advantage over the roots supercharger because its design allows it to move air more efficiently.

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02 ’69 Camaro built
The engine will be going into this ’69 Camaro built as a Pro Street performer by Bryan Lefebvre and his dad. And it’s obviously ready for big power.

The old-school roots supercharger uses the spinning lobes to move air along either side of the case and into the intake plenum. The air exits the supercharger at atmospheric pressure, so boost has to be built up inside the intake plenum.

Meanwhile, a twin-screw supercharger moves air in a cavity created between the screws. As the screws rotate, the cavity moves from the opening in the supercharger case directly to the exit. Meanwhile, the shape of the lobes on the screws also means the cavity gets smaller as the air moves closer to the exit, compressing it. That means the air is already under pressure as soon as it enters the engine.

03 RHS aluminum LS block
The foundation of the build is an RHS aluminum LS block. It will help us reach that big-inch displacement thanks to its 9.750 deck height—just over half an inch taller than the standard LS 9.240 deck.

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But that’s not what matters. Here’s what really matters: When comparing a roots supercharger to a twin screw running at the same rpm, the twin screw will almost always provide more boost, provide boost at a cooler temperature, and have less drag on the engine.

Good stuff all around.

04 stroker forging from K1
The crank is a stroker forging from K1. Where the standard LS3 runs a 4.00-inch stroke, this crank will move the pistons 4.250 inches from bottom to top dead center.

But recently the crew at Whipple Superchargers came up with an updated design that’s supposed to be more efficient than ever before. It is a 3.0L displacement unit, which isn’t significantly larger than its popular 2.9L supercharger design. The big change is it is one for the first twin-screw blowers with a front mouth that doesn’t require a jackshaft to spin the screws from the rear of the case. Instead, this new blower mounts the throttle body on an angle so the incoming air can flow around the driveshaft and into the blower. Sounds simple, but the guys at Whipple say this new design allows the blower to be spun even faster for even more boost.

As this went to press, Whipple’s new 3.0L screw-blower was still so new that they didn’t even have any information about it up on their website. But our friends at Prestige Motorsports in Concord, North Carolina, managed to get their hands on one of the first units for a big-inch LS3-based build and they invited us to check out their build featuring one.

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05 locks down the main caps
Short-block specialist Cody McCleary locks down the main caps after setting the crank in place. Like an LS, the RHS block utilizes six fasteners to secure each main cap, but we’re using studs instead of bolts. Those main studs are torqued to 70 pounds with extreme pressure lube on the threads, and the side bolts are spun down to 20 pounds each.

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Prestige’s engine build is a 454ci LS3 that will be going into a beautiful—and well-built—Pro Street ’69 Camaro. Owner Bryan Lefebvre and his dad have already installed Chris Alston’s Chassisworks suspension, big tubs, and mile-wide rear meats, so it is ready to handle big power. That’s what the big-inch LS and Whipple blower are for.

So, let’s quit wasting time. We’ll get onto the build, and best of all, judgment on the overall package with a little dyno time.

06 pistons are forgings from DSS Racing
The pistons are forgings from DSS Racing. They are sized at 4.125 inches in diameter with a 1.165 compression height. The dish is worth 29 cc and should help keep compression in a manageable range because we’ll be running this engine on 93-octane pump gas. They connect to a set of Eagle H-beam connecting rods with a 0.927 pin. The forged rods are 6.460 inches long.
07 rotating assembly in the block
Here’s a look at the rotating assembly in the block. The RHS block is designed with several features to make running a stroker as long as 4.600 inches possible. This includes the side oil gallery moved outboard to make more room for the crank and cylinder liners and bores that run extra deep into the block. You can see that here and how the bottoms of the bores are notched to make clearance for the big ends of the rods as they swing by.
08 hydraulic roller from Comp Cams
The cam is a hydraulic roller from Comp Cams. It has been ground with 243/259 degrees of duration at 0.050 tappet lift on a 110-degree centerline and a lobe separation of 116 degrees. The lobe lift is 0.385 inches for the intakes and 0.3910 for the exhausts. With 1.7:1 ratio rocker arms that will make the gross valve lift 0.654 of an inch for the intakes and 0.664 for the exhausts.
09 timing set with a longer chain
Another change the engineers at RHS made with their LS block to gain more access for stroker builds is they raised the cam tunnel centerline. This does mean you need a timing set with a longer chain, which RHS can sell you. That’s what you see here. The oil pump high-volume unit.
10 oil pan is a Moroso
The oil pan is a Moroso fully fabricated piece designed to fit F-bodies. It features baffles and kickouts, all designed to help keep oil around the pickup during high-g maneuvers and also has a billet spin-on oil filter adaptor.
11 cylinder heads are Prestige Motorsports’ own castings
The cylinder heads are Prestige Motorsports’ own castings. They are CNC-machined throughout for maximum flow. The combustion chambers are sized at 69 cc, and the intakes are 255 cc, so this is really tuned for big-inch or high-performance LSs.
12 valves for the heads are sized at 2.165 for the intakes and 1.590 for the exhausts
The valves for the heads are sized at 2.165 for the intakes and 1.590 for the exhausts. To help manage the extra heat generated by boost, the exhausts are made from Inconel, while the intakes, which are cooled by the incoming air/fuel charge, are stainless steel.
13 lifters are hydraulic rollers
The lifters are hydraulic rollers. They have tie-bars to keep them from spinning in the lifter bores, so we don’t need the usual LS lifter cups.
14 ls7 heads
To help maintain cylinder sealing, the heads and block are designed to utilize extra fasteners. This includes four studs per side that thread into the head directly above the combustion chambers. They slide through open holes in the block and then nuts are threaded onto the studs from underneath. You have to access these studs through the lifter valley, and it can be a little tough to get the proper torque on these using a crow’s foot on your torque wrench, but it does help when you are pouring on the boost.
15 rockers are stock-style units with a 1 - 7 -1
The rockers are stock-style units with a 1.7:1 ratio. These are from SBI and have a quality captured roller trunion bearing for durability. You must be careful when installing the rockers because the intakes have a slight offset and are slightly different than the exhausts.
16 ls7 run intake spacers
Because of the block’s raised deck we needed to run intake spacers to get the manifold to fit (which is designed for a standard-deck block). Thankfully, RHS expected engine builders to run into this situation and sells spacers specifically for this.
17 ls 7 lower intake plenum
The lower intake plenum goes on next. As you can see, it is wide open with plenty of volume.
18 lowers the intercooler into place ls7
And here’s why the lower plenum is basically a box. Engine assembler Larry Broeker lowers the intercooler into place.
19 underside of Whipple’s new 3.0L blower
Here’s a look at the underside of Whipple’s new 3.0L blower. If you look at the bottom, you can get a glimpse of the twin screws that make the magic happen.
20 blower is ready to be set into position and bolted down
With the intercooler in place, the blower is ready to be set into position and bolted down.
21 blower is spun by a serpentine belt
At the time we were doing this build, the only front drive system that worked with the new Whipple blower was made by Wegner Automotive. But that’s OK because this is a really impressive system. The blower is spun by a serpentine belt. They often get a bad rap with a blower because they are more prone to slipping than a cogged belt. But serpentine belts have an advantage because they waste less horsepower than cogged belts, and the Wegner system minimizes any chances of slipping by getting approximately 180 degrees of belt wrap around both the crank and blower pulleys.
22 ls7 front drivebelt to spin the alternator
And here’s a look with the front drivebelt to spin the alternator also in place. This, too, gets maximum belt wrap.
23 Peak power was 1,035.8 hp at 6,500
On the dyno we were super impressed with this setup. Remember, we’re only burning pump gas here. With a small 3.050-diameter top pulley (the crank pulley is approximately 6.5 inches) we saw just a touch over 12 pounds of boost at 6,700 rpm. Peak power was 1,035.8 hp at 6,500 rpm and peak torque was a healthy 931 lb-ft at 4,200. This is definitely going to be a street beast!
Whipple LS Dyno Sheet
RPM Torque Horsepower Boost (PSI)
3,400 899.1 582.1 11.01
3,500 902.3 601.3 11.06
3,600 906.5 621.4 11.07
3,700 908.4 640.0 11.03
3,800 914.3 661.5 10.98
3,900 922.2 684.8 10.92
4,000 928.6 707.2 10.88
4,100 931.0 726.8 10.84
4,200 931.0 744.5 10.80
4,300 929.6 761.1 10.76
4,400 925.1 775.0 10.72
4,500 918.1 786.6 10.69
4,600 913.3 799.9 10.66
4,700 912.5 816.6 10.64
4,800 915.5 836.7 10.64
4,900 917.4 855.9 10.68
5,000 915.8 871.9 10.71
5,100 913.2 886.8 10.71
5,200 909.4 900.4 10.71
5,300 904.1 912.4 10.73
5,400 898.8 924.1 10.76
5,500 895.4 937.7 10.81
5,600 894.1 953.3 10.87
5,700 894.8 971.1 10.94
5,800 894.4 987.7 11.02
5,900 890.8 1000.7 11.11
6,000 885.6 1011.7 11.20
6,100 877.3 1019.0 11.27
6,200 866.8 1023.3 11.35
6,300 857.1 1028.1 11.44
6,400 847.3 1032.5 11.52
6,500 836.9 1035.8 11.66
6,600 824.1 1035.6 11.90
6,700 808.8 1031.8 12.21

Prestige Motorsports
(704) 782-7170

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