Kenne Bell Twin-Screw Supercharger - Force-Fed Atmosphere

Strap a blower to your fifth-gen and let the good times really roll

Camp 1212 01 O_kenne Bell_twin Screw Supercharger 1/29

The Kenne Bell 2.8-liter twin-screw supercharger is perfect to stuffing a lot more performance into an otherwise stock LS3 engine. For those want even more they also offer 3.6L and 4.2L versions.

The newest iteration of our beloved Camaro is, to be kind, on the heavy side. And the quickest way to make it feel “lighter” is to up the car’s power output. It’s all about the power-to-weight ratio, which is why a 30hp go kart can feel scary fast and a 436hp ’10 Camaro can feel, well, not fast enough. Once you have the epiphany that your Camaro needs more power, then the big question becomes, “How?” Well, one answer is forced induction. Slamming more atmosphere into your LS3, L99, or any engine, is the quickest way to boost output and ratchet up the fun factor of your Camaro.

Kenne Bell has been in the twin-screw supercharger business for over 20 years and they have a line of positive-displacement blower kits specifically designed to fit under the hood of GM’s newest generation of Camaro. Their blowers come in 2.8L, 3.6L, and ginormous 4.2L variations, with the 2.8L being perfect for an otherwise stock Camaro.

The blower is a twin-screw arrangement and has very little parasitic loss; up to 100 hp less. This, along with their larger displacement, and uber-efficient 4x6 rotor profiles means more power is generated from each pound of boost, and after all, it’s all about power. They can also churn out more boost (up to 15 pounds) before needing to move from a standard six-rib to a more expensive eight-rib belt system.

Actually, there’s more to a blower than just the power output. According to Kenne Bell, their superchargers are whisper quiet with no gear growl, and the oil dipstick is far easier to deal with than the typical sight glass. Another key to the unit’s performance is their “dual pass” intercooler and heat exchanger system. Again, cooler air equates to more power. See a theme developing here?

Superchargers such as this are termed “positive displacement” since compression happens within the blower. Instead of air being drawn in through the top like a typical Roots unit, it’s drawn in through the inlet port and pushed into the engine along the axis of the rotors. The intake is positioned on the end of the two screws, which are designed to overlap but not touch, leaving a small gap or pocket. As the screws turn, the gap gets smaller. This compresses the air as it moves along the screws up to the point where it enters the intake. The rotors, instead of having nearly straight lobes, are twisted into a steep helix shape. Thanks to a vacuum-referenced bypass valve, the inlet pressure is equalized with the manifold pressure. This pretty much negates any parasitic loss while cruising and makes for a very efficient design.

As for the kit, it retails for $6,999 and comes complete including a Boost-A-Pump fuel system, 47lb injectors, billet fuel rails, Mammoth cold-air kit, and all the fittings and hardware needed. For another 300 bucks you can upgrade the blower to the liquid cooled version, which under severe high-boost conditions, can dramatically lower the temp of the oil in the blower, up to 200 degrees.

At over 190 pages and 500-plus images, they also have one of the most detailed instruction manuals we’ve come across. This is a good thing, since while the kit isn’t hard to install, it does fall on the complicated side of the bell curve. As Jim Bell told us, “our primary goal with the standard 8-psi 2.8L Mammoth system was to offer a kit that would maximize airflow and horsepower so costly upgrades (supercharger, inlet system, MAF meter, manifolds, intercooler, etc.) were not necessary up to 1,000 hp. If you ever want more power, you simply need to buy the larger blower and bolt it on, the rest of the system is good to go.”

So, let’s take a quick look at how their system bolts under the hood of a fifth-gen Camaro.

1. Before the new stuff can start making loads of power, the stock stuff needs to vacate the area. First up is removing the stock airbox and engine cover. To say the instruction manual from Kenne Bell is “step-by-step” would be a huge understatement; it’s 190 pages with well over 500 images. So, while the install is complicated, it’s certainly doable for the average gearhead.

Camp 1212 02 O_kenne Bell Twin Screw Supercharger_factory Airbox 2/29

2. To get more room to work, the coolant was drained and the radiator and fan assembly were removed.

Camp 1212 03 O_kenne Bell Twin Screw Supercharger_radiator And Fan Assembly 3/29

3. Blowers love to spin hard, which can actually cause the pressed-on crankshaft pulley to spin on the crank snout. This is bad. To remedy this, Kenne Bell provides a kit to pin them together. The first step was to install this jig. We then drilled two holes with the supplied bit and used a hammer to tap the pins into place.

Camp 1212 04 O_kenne Bell Twin Screw Supercharger_crank Snout 4/29

4. After unhooking the fuel system and unplugging the wiring harness, we unbolted and removed the factory LS3 intake. With the intake gone, we used some tape to temporarily close off the intake ports on the heads.

Camp 1212 05 O_kenne Bell Twin Screw Supercharger_factory LS3 Intake 5/29

5. In preparation for plumbing in the intercooler, we disconnected the heater hoses from the engine as well as where they go through the firewall.

Camp 1212 06 O_kenne Bell Twin Screw Supercharger_heater Hoses 6/29

6. The rear heater core hoses were modified using the supplied 90-degree bends. This will help them clear the blower assembly.

Camp 1212 07 O_kenne Bell Twin Screw Supercharger_rear Heater Core 7/29

7. After pulling the driver-side black plastic inner wheelhouse, we removed the windshield washer reservoir tank to make room for the huge 4.5-inch intake system. Kenne Bell supplies a new washer bottle to take its place elsewhere in the engine bay.

Camp 1212 08 O_kenne Bell Twin Screw Supercharger_windshield Washer Reservoir Tank 8/29

8. Using a 10mm wrench, we removed the thermostat assembly and replaced it with a 180-degree version.

Camp 1212 09 O_kenne Bell Twin Screw Supercharger_thermostat Assembly 9/29

9. After removing the nose of the Camaro, we tackled installing the intercooler. The air dam was modified to allow for maximum flow and the lines were run back through to the intercooler pump (arrow).

Camp 1212 10 O_kenne Bell Twin Screw Supercharger_air Dam 10/29

10. Above the intercooler pump, we mounted and plumbed in the preassembled intercooler reservoir.

Camp 1212 11 O_kenne Bell Twin Screw Supercharger_intercooler Reservoir 11/29

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