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Product Spotlight: Fleece Performance Engineering’s Exhaust Brake

The 6.7L Cummins is a beast. From the factory—and depending on the model year—you get 350 to 400 hp, 650 lb-ft to 930 lb-ft of torque (1,000 lb-ft on ’19-newer models) and a variable geometry turbocharger that doubles as an exhaust brake right out of the box. Unfortunately, the Holset HE351VE turbo is restrictive in nature and is oftentimes unreliable, too. For added performance potential and ultimate durability, many ’07.5-newer Ram owners ditch the stock charger for a fixed geometry unit, usually an S300 or (more commonly) an S400 series unit from BorgWarner. However, in doing so they also give up the beloved and highly effective exhaust brake option, which relies on the factory turbo’s variable geometry functionality to also act like a turbo brake for added stopping power.

Luckily, the long-awaited exhaust brake system from Fleece Performance Engineering has arrived, and it’s changed the game completely. With it, you get braking performance that mirrors the factory exhaust brake’s impressive functionality, a plug-and-play wiring harness that actually uses the OEM VGT actuator connection point and you activate the exhaust brake using the factory button on your truck’s dash. No vacuum or air lines, air pumps or belts to install—this baby is 100-percent electronic. For a quick look at all the parts and pieces included in Fleece’s new exhaust brake, along with what it takes to install one on a fourth-gen Ram, keep scrolling.

An S400-Equipped Ram’s Best Friend

Fleece Performance Engineering Exhaust Brake System

As a producer of comprehensive turbo systems that allow 6.7L Cummins owners to replace the factory Holset variable geometry turbo with a fixed geometry S400, Fleece Performance Engineering was very aware that its customers missed the factory exhaust brake option once it was gone. But, being the problem-solving type of company they are, they set out to bring exhaust brake functionality back to the table so customers could enjoy the added reliability and performance of an S400 while also being able to stop sooner. The exhaust brake and actuator assembly, wiring harness, S400 cast elbow, downpipe, V-band clamps, coolant lines and fittings are all included in Fleece’s system, which retails for $1,999.

Butterfly Valve

Exhaust Brake Butterfly Valve

Just as conventional exhaust brake systems do, a butterfly valve is employed to control exhaust flow. Closing the butterfly creates restriction in the flow of exhaust leaving the turbocharger (i.e. back pressure), which acts as the braking force for the engine. The butterfly valve is positioned between the supplied cast elbow and downpipe during assembly. And thanks to Fleece’s exhaust brake being fully-electronic, there are no noisy air pumps, frozen air lines or all-day installation times to contend with. In fact, on most trucks its system can be installed in less than two hours.

Heavy-Duty Actuator

Electric DC Motor Actuator

The butterfly valve in the exhaust brake assembly is opened and closed via this heavy duty actuator. The all-electronic, commercial-grade actuator features a high-torque brushless DC motor for precise operation. Its gear train is liquid-cooled for optimum longevity, is the reason Fleece includes cooling lines with the exhaust brake system and it’s also why you’ll have to drain all coolant before you get started with the exhaust brake install.

Pull the Fender Well Liner

2012 Ram 2500 Inner Fender Well Liner

It definitely pays to pull the passenger side inner fender well before you get too deep into the install. With this barrier out of the way you can reach the backside of the turbo, the coolant port you’ll need to access beneath the oil filter base and install the included coolant riser delete hose (required when you go from the factory, coolant-fed turbo to a charger that only needs oil). And because you’ll have to do a lot of work from up above, it’s also a good idea to pull the air intake assembly out of the way, too.

Cast Discharge Elbow

S400 Cast Elbow Cummins Exhaust Brake

Designed to bolt directly to any standard S400 turbine housing with a 4-5/8-inch (od) V-band outlet flange, the cast discharge elbow should be attached to the aforementioned exhaust brake assembly prior to being connected to the turbo. Mocking up, clocking and then installing the two items as a single unit makes life much easier later on, when installation of the downpipe can warrant some re-orientation of this section of the system.

Second-Gen Exhaust Manifold

Second-Gen Cummins Exhaust Manifold

Ditching the factory turbocharger in favor if an S400 is referred to as a second-gen turbo swap. The nucleus in these kits is the use of a second-gen (’94-‘02) Cummins style exhaust manifold, with its outlet flange positioned centrally (and typically of the T4 divided type). Centrally locating the turbo creates equal flow to the turbine wheel, which makes the exhaust side much more efficient and leads to vastly improved drivability. In fact, most 6.7L Cummins owners notice very little difference in lag after switching from the factory Holset to a considerably larger S400. For comparison’s sake, the stock manifold is pictured on top of an aftermarket second-gen style version from Steed Speed above.

Cooling the Exhaust Brake

Coolant Supply Port Cummins Exhaust Brake

Because the actuator is liquid-cooled, the coolant supply originally intended for the factory VGT gets repurposed to feed this vital portion of the exhaust brake. The same coolant feed port on the block near the oil filter housing is utilized thanks to the 18mm to -6 AN male JIC adapter (and sealing washer) Fleece supplies. Then the included (and pre-cut) coolant rise delete hose and 3/8-inch coolant hose can be installed.

4-inch Downpipe

4-inch Aftermarket Cummins Downpipe

The supplied 4-inch diameter downpipe is made of stainless steel and bolts right up to any existing 4-inch aftermarket exhaust system. However, a 5x4-inch reducer pipe will be in store for trucks with 5-inch diameter exhaust systems. An extra set of hands is always helpful when installing (and then tweaking) a new aftermarket downpipe. The last thing you want when you’re finished with the install is a dreaded downpipe rub or excessive stress on any of its connection points.


OEM Electrical Connector Cummins Exhaust Brake

For seamless integration on the wiring side, the exhaust brake’s electrical connector plugs into the factory VGT connector. No calibrating is necessary to get the exhaust brake to function properly, it’s completely plug-and-play right out of the box. The CAN-based control system and heavy-duty actuator allows for split-second, confidence-inspiring braking responsiveness. As you might’ve guessed, this makes the exhaust brake button on the dash functional again. And once again you’re saving your truck and trailer brakes when moving heavy loads.

Modes of Operation

Ram 2500 Cummins Exhaust Brake Button

In full-on mode, the exhaust brake activates with 0-percent throttle at any vehicle speed over 10 mph—and prompts the quickest response time from the exhaust brake. In automatic mode, the exhaust brake will activate at any speed higher than 10 mph when the brake pedal is applied (and throttle is 0-percent). In cold-start, warm-up mode, the exhaust brake will partially close with the engine idling in order to bring coolant temp up faster (to 150 degrees F).

The factory turbo is just one of the performance roadblocks your 6.7L Cummins faces. Find out what else is holding you back here.

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