More Air, Stock Fuel, Big Power

Installing No Limit Fabrication’s Compound System on a Brand-New ’19 Ford

In the past, we’ve shown you how tuning alone can bring a ’15-present 6.7L Power Stroke up to speed in a hurry. As in, a 540hp and 1,100 lb-ft at the wheels “hurry.” But with everyone and their brother rolling around in tuned, 540hp late-model Super Dutys, some of us want a little something extra to stay ahead of the curve. Given the untapped potential that exists in the factory ’15-newer injection system, bringing more air into the equation can yield impressive results. A 63- to 64-mm VGT upgrade on its own can add 50-60 hp on stock-fuel 6.7Ls, but what about adding a set of compounds to the mix? The folks at Flynn’s Shop in Alexander, Illinois, were about to find out.

The lucky recipient of No Limit’s add-a-turbo kit was this 500-mile ’19 F-350, spec’d in Limited trim. As expected, with the truck being only weeks old, everything came right apart for the guys at Flynn’s Shop.

With a customer looking to transform his already-capable ’19 F-350 Limited into an even more capable weekday workhorse/weekend play toy, No Limit Fabrication’s add-a-turbo kit caught his eye. By retaining the factory 61mm GT37-based Garrett VGT and adding a proven 76mm Precision turbo in front of it, No Limit’s system provides quick-spool up, instant torque, and impressive top-end gains. Convinced, the owner pulled the trigger and Flynn’s got to work. Throughout the extensive install, we were pleased to find that very little fitment issues surfaced, top-quality hardware was included, and the end result was a truck that drives like stock until you feel the need to shred the rear Michelins.

If you’re in the market to go beyond the types of mods the average Joe is making to his late-model Super Duty, this compound system is a great start.

What’s better than a tuned late-model 6.7L Ford? A tuned late-model 6.7L Ford with a 76mm Precision turbo onboard! If you’re looking to capitalize on the awesome fueling of the air-limited 6.7L Power Stroke, or even if you plan to add a stroker pump and larger nozzles, No Limit Fabrication’s compound turbo system won’t disappoint you.
No Limit Fabrication’s add-a-turbo style compound system for the 6.7L Power Stroke combines a 76mm charger from Precision Turbo & Engine with the factory 61mm VGT in the valley and is capable of supporting more than 800 rwhp. In addition to the Precision charger, the kit comes standard with a heavy-duty turbo mount, two-piece hot-pipe, two-piece downpipe, intermediate charge pipe, battery relocation tray, cold air intake, and all the hardware that’s necessary to make the system work. Here, you can see that the polished version of the company’s optional 304 stainless steel intake piping kit was also ordered.
Designed and capable of supporting 1,350 hp on its own, Precision’s GEN2 PT7685 CEA turbo means business. It sports a 2618 forged-aluminum compressor, CNC machined to perfection and with a 76mm inducer. The 76/85 as it’s often referred also utilizes a healthy map groove and calls for a 5-inch diameter intake to feed air to it. While the 76/85 comes standard in No Limit’s compound kit, larger 83mm and 86mm compressor options are also available. A 4.2-inch compressor outlet makes use of a V-band connection.
On the other end of the turbo’s shaft you’ll find an 11-blade turbine wheel with an 85mm exducer. It’s worth noting that, no matter which compressor wheel you spec out with No Limit (76, 83, or 86mm), the same turbine is employed. A 1.12 A/R exhaust housing is being used here, although Precision does offer a larger, 1.28 A/R housing for its GEN2 PT7685 CEA.
For superior thrust capacity, quicker transient response, and off-idle spool-up, the 76/85 Precision features a dual ceramic ball bearing center section. And in addition to being lubricated and cooled via engine oil, the center section is also air-cooled (notice the finned casting just above the oil drain area). This turbo’s use of a divided T4 turbine inlet also aids responsiveness (over what the common T6 inlets in most compound systems provide).
Once the engine oil and coolant had been drained, the brand-new air intake, hot- and cold-side intercooler tubes, and upper and lower intake manifolds were removed. Then Chad Flynn of Flynn’s Shop turned his attention toward getting rid of the factory downpipe, which called for the removal of the passenger-side inner fender well liner in order to access it.
Part of adding any compound turbo system onto an engine calls for an additional oil drain for the atmosphere turbo. This billet-aluminum oil pan from No Limit includes a provision to accept a large drain for the Precision charger. It also comes with a magnetic drain plug in the bottom and adds 3 quarts of oil capacity, bringing the overall total to 4 gallons (or 16 quarts).
Before getting too carried away with the turbo install (and with the oil drained and factory pan removed earlier on), Flynn went ahead and installed the No Limit pan. Machined to accept an O-ring seal, the supplied O-ring was pressed into place, but for extra insurance a layer of silicone was added on top of that. Securing the pan to the 6.7L block called for use of the included stainless steel mounting hardware.
A No Limit crankcase breather kit was also added before things got busy with the piping that would eventually make the back of the driver side valve cover harder to get to. However, instead of venting blow by to atmosphere (and having the occasional smell of 10W-30 drift into the cab), a venturi from No Limit was installed in the exhaust system.
Prior to installing any of the compound system’s piping, Flynn installed the pyrometer probe in the passenger side exhaust manifold. Soon he would discover that the wire coming off the probe would just clear the turbo kit’s hot-pipe.
The beauty of an add-a-turbo kit is that everything bolts in front of or around the stock turbocharger. Not even the factory up-pipes had to be removed during the install. Here, Flynn has the wrap-around section of the two-piece hot-pipe loosely installed on the back of the factory turbo and is mocking up where the second pipe will be mounted.
Two extra holes are included on the firewall side of the exhaust collector flange that’s part of the hot-pipe. The supplied bolts are used to tie this section of hot-pipe into a billet extension mated to a valve cover plate to support the Precision turbo. Flynn made sure to use Loctite on all turbo mounting bolts.
Ultra-tight working quarters dictate that the upper section of the kit’s two-piece 4-inch downpipe be installed before the turbo—and even then things are extremely close. To avoid having to inch the downpipe into place, installing it before the hot-pipe sections went on would’ve also paid big dividends. Either way, the downpipe has to be installed well before you think about mounting the big Precision.
Because of its proximity to the PCM, Flynn added Design Engineering Inc. exhaust wrap to the downpipe. This will help keep heat off of the computer—as well as everything else located near the cowl—while also aiding spool up.
Easing the mounting process for the Precision charger, Flynn split the turbo and attached the turbine housing to the hot-pipe first. In hindsight, mating the housing to the hot-pipe with both components off the engine would’ve made installing (and then tightening up) all turbo mounting bolts a bit simpler.
After that, the supplied T-bolt hot-pipe clamps were tightened up and the heater core coolant tube was reinstalled. Then the lower section of the downpipe was installed and the top section was connected to the Precision charger’s turbine housing.
Prepping the turbo sub-assembly for installation, Flynn bolted the oil drain flange to the center section. It seals to the center section via O-ring. The supplied oil drain line would be attached and routed to the fitting in the previously-installed billet oil pan later on.
With the turbine housing and downpipe permanently in position, the compressor housing, center section, and turbine wheel portion of the Precision charger was carefully rejoined with the turbine housing. Dual V-band clamps make re-clocking the center section and compressor housing a cinch.
As for clocking the center section, the oil feed port was positioned straight up and down. The Precision turbo receives its oil supply from the oil filter housing. No Limit supplies a T fitting that retains the factory engine oil temp sensor while simultaneously accommodating the included oil feed line.
Following a quick mockup of the intermediate charge pipe, the compressor housing was clocked with its outlet facing the driver side fender. With fitment looking good, the compressor housing’s clamp was tightened up and the supplied T-bolt clamps were cinched down on the reducer boot, securing the intermediate pipe to the factory turbo.
A slightly larger diameter hot-side intercooler pipe is included with No Limit’s optional intake piping kit. Flynn reused the proven OEM silicone boots at both the compressor outlet and intercooler end of the pipe, but No Limit’s stronger T-bolt clamps were employed to ensure the boots never try to relocate themselves under big boost.
For a superior seal, the flanges of both the intake Y and 90-degree elbow in No Limit’s intake piping kit incorporate the factory O-rings. The intake Y pipe also accommodates the factory MAP sensor (on the passenger side). Here, Flynn can be seen transferring it over to the intake Y pipe.
The connection between the driver side intake and the intake Y-pipe is made both rigid and flexible thanks to No Limit’s inclusion of an HD quick release clamp from Vibrant Performance. Using a clam shell design along with high-temp O-rings, the Vibrant clamp offers 12 degrees of axial movement—perfect for charge pipes that require some flexibility.
With the piping install essentially done, Flynn set about tidying up both engine harnesses and plugging the exhaust back pressure and MAP sensors back in. Other finishing touches included orienting the turbo and piping clamps in a way that facilitated easy removal, should the need to remove them ever arise. To clean up the overall under hood look, Flynn would even cut down a few bolts on some of the T-bolt clamps.
Because the Precision turbo’s positioning at the front of the passenger side valve cover pushes everything so far forward, No Limit supplies a 90-degree billet cold air intake elbow to mount the air filter. One of No Limit’s polished battery trays relocates the passenger side battery closer to the firewall, which makes room for the supplied S&B filter.
The finished install of No Limit Fabrication’s compound system looks something like this. While installing this system is highly involved, we have to say it’s one of the better add-a-turbo kits we’ve come across. The welds are beautiful, much of the piping features V-band connection points (and beaded ends when they aren’t present), and the overall fitment is as close to precise as you’ll see in the diesel industry. Of course, the 76mm Precision’s ability to free up and support a lot of additional horsepower is the main objective, but ease-of-install was definitely a bonus.


Flynn’s Shop

No Limit Fabrication

Precision Turbo & Engine

Vibrant Performance

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