By now, most of you know the GT32 SST single-sequential turbo found on 2011 to 2014 Ford 6.7L Power Strokes has several shortcomings. In the aftermarket, a simple programmer can (and oftentimes will) push the tiny, twin-compressor-wheel turbo over the edge. The 41mm-inducer turbo makes for a rocket ship out of the hole, but unfortunately a quick 60-foot time is the most impressive part of a tuned, late-model Ford’s 14-second trip through the quarter-mile. On the dyno, we’ve never been able to get more than 445 rwhp out of a programmed 6.7L due to the GT32 running out of steam well before 3,000 rpm.
Midwest Diesel & Auto is one of several companies committed to unleashing the power potential of the 6.7L. The Central Illinois Power Stroke gurus recently brought an S300 turbo kit to market for 2011 to 2014 trucks, and we met them at Randall’s Performance to test it on the dyno. What we found was a truck with stock-like spool up, impressive mid-range and top-end power gains, and great towing manners. On top of that, the Ford never sees more than 1,250 degrees on the pyrometer—despite having the H&S Mini Maxx set on Hot. Read on to get up close and personal with this all-inclusive turbo kit.
| Midwest Diesel Turbo Upgrade For 2011 014 Ford 6 7L Power Stroke 02 The Kit
At the heart of Midwest Diesel & Auto’s S300 kit lies a BorgWarner S366. The intake and exhaust plumbing, flanges, and downpipe are all made of stainless steel, replacing the plastic factory pieces. Completely bolt in, the kit retails for $4,150.
| Midwest Diesel Turbo Upgrade For 2011 014 Ford 6 7L Power Stroke 03
Based on its reliable track record, great driveability characteristics, and performance potential, the popular S300-framed turbocharger from BorgWarner got the nod for Midwest Diesel’s kit. A billet pedestal, cast T4 adapter (from a Duramax application), oil supply and return lines, and all hardware are included. Essentially, any S300-based charger can be used with this system, and Midwest offers the box stock S363, as well as billet-aluminum and forged milled compressor wheel options in addition to the S366 tested this month.
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Key specs for the T4-flanged S366 are its cast 66mm compressor wheel (inducer), 73mm turbine wheel (exducer), and .91 A/R non-wastegated turbine housing. Originally intended for a common-rail 5.9L Cummins application, the turbo’s compressor housing outlet elbow provides a straight connection point for the hot-side intercooler pipe (ruling out blown boot scenarios under boost).
| Midwest Diesel Turbo Upgrade For 2011 014 Ford 6 7L Power Stroke 05
A two-piece downpipe makes for an easy install, and thanks to its stainless steel construction you won’t ever have to worry about this portion of the exhaust rusting out. After clearing the firewall, the downpipe transitions from 3.5 inches (od) to 4 inches.
| Midwest Diesel Turbo Upgrade For 2011 014 Ford 6 7L Power Stroke 06
Ceramic-coated, heat-resistant up-pipes are also included in the kit as an add on (an external wastegate option is also available). If the up-pipes appear short to you, remember that the 6.7L engine has reverse-flow heads, so the distance the exhaust has to travel from both banks to the turbo is very minimal.
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With all the factory plumbing (and turbo) removed and the pedestal and T4 adapter installed, the S366 went in.
| Midwest Diesel Turbo Upgrade For 2011 014 Ford 6 7L Power Stroke 08
An S300 appears right at home in the 6.7L’s lifter valley, doesn’t it? To kill two birds with one stone, the guys at Midwest recommend bolting the downpipe to the S366 before bolting it on.
| Midwest Diesel Turbo Upgrade For 2011 014 Ford 6 7L Power Stroke 09
Air enters the engine via a stainless steel Y-pipe that transitions from one 3-inch tube into two 2.25-inch tubes feeding each side of the intake manifold. Vibrant Performance reinforced silicone boots are included for each connection point, and stainless steel, spring-loaded T-bolt clamps (also from Vibrant) are included for every connection point that sees boost.
| Midwest Diesel Turbo Upgrade For 2011 014 Ford 6 7L Power Stroke 10
Accommodating some of the most popular cold-air intake systems on the market, the kit works in conjunction with both AFE and S&B air intake systems. And, like everything else in Midwest’s kit, the 4-inch air intake tube is made of stainless steel.
| Midwest Diesel Turbo Upgrade For 2011 014 Ford 6 7L Power Stroke 11
The intake tube also has a provision for re-mounting the factory mass airflow sensor (MAF).
| Midwest Diesel Turbo Upgrade For 2011 014 Ford 6 7L Power Stroke 12
Midwest tunes its 2011 F-250 with an H&S Mini Maxx, which provides the ability keep an eye on boost, EGT, injector pulse width, and rail pressure. In order for the factory CP4.2 injection pump to maintain adequate rail pressure, just 1,440 microseconds of pulse width is commanded in the H&S Hot tune. When the truck sailed past 500 hp on the rollers, rail pressure never dipped below 28,000 psi.
| Midwest Diesel Turbo Upgrade For 2011 014 Ford 6 7L Power Stroke 12 Front View On The Dyno
On the SuperFlow chassis dyno at Randall’s Performance, the truck made 39 psi of boost, with EGT never topping the 1,250-degree mark. On the street, the truck sees 42 psi of boost and EGT is even lower than that on deliberate, prolonged, wide-open-throttle runs.
| *SuperFlow load-cell dyno
*SuperFlow correction factor
*Runs made in Fifth gear, from 65 to 110 mph
*30 percent load applied
As it turns out, a free-flowing, moderately sized S300 is just what the doctor ordered for the 2011 to 2014 Power Stroke. Thanks to the engine’s 6.7L of displacement, it has no problem spooling the 66mm charger and, as is evidenced in this dyno graph, the power band extends all the way out to 3,400 rpm before horsepower starts to fall off. By comparison, the factory turbo maxes out horsepower at 2,600 rpm. As you might’ve imagined, the broader power curve the S366 provides makes the truck a lot more fun to drive on the street. Keep in mind that, on this same dyno (and with the same H&S Hot tune), 2011 to 2014 Super Dutys sporting the factory turbo make between 435 and 445 hp. In our eyes, this means Midwest Diesel & Auto’s S300 turbo kit is good for at least 70 hp over the stock charger. Picking up 70 hp with a simple turbo change is impressive at high horsepower levels, but it’s even more impressive at the 500hp mark. It just goes to show you how much the stock turbo is holding back the performance potential of 2011 to 2014 6.7L Power Strokes.
| Midwest Diesel Turbo Upgrade For 2011 014 Ford 6 7L Power Stroke 15 Rear View On The Dyno
