Equipping A '99 Dodge Ram With A Variable-Geometry Turbo

When a Holset variable-geometry turbocharger (VGT) came as standard equipment on the 6.7L Cummins engine for the '071/2 model year, it was a major eye-opener. Thanks to its capability of varying the exhaust housing's aspect ratio (A/R) depending on engine speed, the Holset HE351 provided instant spool-up and unmatched responsiveness from idle to 3,000 rpm. The icing on the cake was its built-in, electronically actuated exhaust brake, which made the medium-duty Cummins engine even more suited for towing.

But it wasn't only an eye-opener to those seeking brand-new Rams-the aftermarket took note as well. And it was only a matter of time before this modern technology was embraced and found its way onto older, 5.9L engines. One company that has found a niche for the Holset HE351 VNT turbo is Fleece Performance Engineering, and the folks there were in the middle of installing one on a modified '99 Dodge Ram 3500 when we stopped in.

After the owner of the 24-valve Cummins added a fuel system, 100hp injectors, an Edge Comp box, a dual-disc clutch, and an aftermarket turbo, he still experienced turbo lag, excessive smoke, and power that felt more like an On-Off switch than smooth or progressive. So the truck was brought to the experts at Fleece, who not only sell and install HE351s but also make their own stand-alone turbo controller. Check out how easy the install went, how the turbo and exhaust brake are controlled, and how big of an improvement it made in the truck's performance.

Feedback From The Owner:
This is an email the owner of the truck sent Fleece Performance Engineering a few days after the install, once he'd collected some data on the truck's new setup:

"I just wanted to tell you [Fleece] and the rest of your folks that it was a very pleasant experience Wednesday. What you all can do there is incredible. I am very, very pleased with the VGT turbo and what it can do. I had a blast going home that evening. Playing with the dial and turning on the exhaust brake was cool. It did lower the exhaust gas temperature, and I am going to hook up our horse trailer tonight and head to the fairgrounds, so I'll get to see more tonight as well. It is awesome how quick it spools now, and I don't have to wait on it."

PRICE LIST:
*Holset HE351 turbo (core):	$100 to $600
*6.7L exhaust manifold (core):	$100 to $200
*'03 to '07 5.9L downpipe (core):	$150 to $250
Stand-alone VGT controller:	$624.75
	with exhaust brake option
Labor:	$450 to $600
Total:	$1,424.75 to $2,274.75
*Prices on core parts may vary depending on where they're purchased

• 

  First things first: The laggy, 56mm-diameter-inducer S300 turbocharger was removed, followed by the stock exhaust manifold. The owner's main gripe about this aftermarket turbo was that its low-end response was slow. Another concern was that with his trailer in tow, the engine would bellow black smoke until the turbo lit, which resulted in high EGT and smoking out his horses.

  

  First things first: The laggy, 56mm-diameter-inducer S300 turbocharger was removed, follow
• 

  With each turbo's compressor housing removed, we measured the difference between the Holset HE351 VGT (right) and the S300 (left). The S300's compressor wheel inducer diameter measured 56 mm, which is the same size as the stock Holset HX35's that came on '981/2 to '02 manual transmission trucks. The main difference between the S300 removed and a stock HX35 is a 14cm exhaust housing versus a 12cm housing. However, the compressor inducer size on the HE351 measured 60 mm-a nice upgrade from the 56 mm that came off the engine.

  

  With each turbo's compressor housing removed, we measured the difference between the Holse
• 

  Another difference between the aftermarket charger and the HE351 is in the exhaust housings. The S300 had a fixed, 14cm exhaust housing, while the HE351's variable-geometry technology allows the exhaust housing to be as large as 26 cm at wide-open throttle, or act as a small, 9cm housing at lower engine speeds.

  

  Another difference between the aftermarket charger and the HE351 is in the exhaust housing

• 

  Because the factory backpressure sensor wouldn't be needed, it was deleted. The guys at Fleece simply ground down the port, tapped the hole, and utilized it for the pyrometer's thermocouple. From there, the core HE351 exhaust housing and 6.7L exhaust manifold (only the 6.7L manifold can be used) were painted black, and the compressor housing was hit with a coat of silver. Because the 6.7L exhaust manifold and turbo assembly were being used, a 4-inch downpipe from a third-generation 5.9L application was utilized in order for the exhaust system to bolt up correctly.

  

  Because the factory backpressure sensor wouldn't be needed, it was deleted. The guys at Fl
• 

  Another carryover part from the 6.7L is the oil drain tube, which required relocating the oil drain location. This freeze plug (arrow), located next to the downpipe along the block, was removed and used as the new oil drain point for the turbo.

  

  Another carryover part from the 6.7L is the oil drain tube, which required relocating the
• 

  Prior to installing the 6.7L exhaust manifold, each exhaust port on the cylinder head was cleaned up using an angle-grinder and a 3M Scotch-Brite pad. Then, the new turbo and exhaust manifold were installed at the same time by leaving them bolted to each other.

  

  Prior to installing the 6.7L exhaust manifold, each exhaust port on the cylinder head was

• 

  From there, each exhaust manifold gasket was replaced (PN 3946275) and each exhaust manifold bolt was torqued to the recommended 32 ft-lb.

  

  From there, each exhaust manifold gasket was replaced (PN 3946275) and each exhaust manifo
• 

  Fleece Performance's stand-alone controller for the HE351 VNT turbo taps into the engine's CAN-bus system. It allows you to engage or disengage the exhaust brake with a toggle switch (red arrow), as well as control boost using a user-dial (blue arrow), such as how far open or closed you want the nozzles in the turbo-more closure meaning more restriction, i.e. stronger braking power.

  

  Fleece Performance's stand-alone controller for the HE351 VNT turbo taps into the engine's
• 

  The toggle switch and dial control can be mounted anywhere you want in the cab, and Fleece even makes its own mounting plate for manual transmission customers.

  

  The toggle switch and dial control can be mounted anywhere you want in the cab, and Fleece

• 

  Because the stand-alone controller monitors the CAN-bus system on '981/2 to '02 engines, the harness gets plugged into the factory three-pin CAN-bus port on the front, driver side of the engine. The rest of the wiring simply piggybacks from there, intercepting the MAP signal as well.

  

  Because the stand-alone controller monitors the CAN-bus system on '981/2 to '02 engines, t
• 

  For power, Fleece tapped into the key-to-ignition switch. It's the red wire (arrow) tied into the main wiring cluster along the firewall.

  

  For power, Fleece tapped into the key-to-ignition switch. It's the red wire (arrow) tied i
• 

  The Fleece stand-alone controller box was plugged in and mounted on top of the relay box under the hood with Velcro. The remaining wiring for the toggle switch and user dial were fed into the cab through an existing hole in the firewall. From there, all loose wiring was zip-tied and the switches were mounted on the truck's dash.

  

  The Fleece stand-alone controller box was plugged in and mounted on top of the relay box u

• 

  Once the turbo harness was plugged in, the ignition was turned to the On position and we listened to the actuator move the nozzles up and down inside the turbo while rotating the user-dial from 100 percent closed to 100 percent open. Then, with a laptop hooked up to the stand-alone controller box, the parameters for the HE351 turbo and its exhaust brake were programmed in. The maximum boost level for the new turbo was set at 40 psi in order to avoid overspeeding it, and the exhaust brake was set to come on when the throttle position sensor reaches 0 percent (so it will only engage with zero throttle input, and with the toggle switch on-just like a Class 8 truck).

  

  Once the turbo harness was plugged in, the ignition was turned to the On position and we l
• 

  With the downpipe, exhaust system, and air intake bolted back up, the truck was fired up and taken for a testdrive. We immediately noticed zero turbo lag, only a slight hint of smoke under wide-open throttle acceleration, and increased stopping power thanks to the exhaust brake. The owner of the truck should now have no problem getting up to speed with his horse trailer behind him-not to mention he'll save his trailer brakes by utilizing the exhaust brake.

  

  With the downpipe, exhaust system, and air intake bolted back up, the truck was fired up a

SOURCES
Fleece Performance Engineering 2463N 625W North Salem IN  46165 765-676-5063 www.fleeceperformance.com

By Mike McGlothlin

Enjoyed this Post? Subscribe to our RSS Feed, or use your favorite social media to recommend us to friends and colleagues!