Part Eleven: Boost It Up Baby
Part eleven of this project build. Can you believe it?! Almost an entire year into this old Ford build-up and we’re rounding third headed for home. This truck has made quite the transformation from its well used 220,000 mile 24-year old self into what it is today. New suspension, new steering, some cosmetic upgrades and most recently a completely new fuel system from tank to heads. With only a couple of scheduled articles left for this build, we’ve held some of the best upgrades for last. With our 205cc Full Force Diesel injectors and now the Strictly Diesel electric fuel system conversion, the fuel side of our performance upgrades are complete, now we address the airflow side. Finally, Project Obsessed gets a heavy breathing turbocharger upgrade.
KC300x Stage 2 Turbo
After some time on the phone with Charlie Fish, owner at KC Turbos, a shop that specializes in Power Stroke turbochargers, we were able to discuss the goals for the build. What we’d be using the truck for. What kind of power we’d like to make. Drivability and smoke concerns. What he suggested was they’re latest rendition of their stock replacement KC300x turbocharger with a 63m compressor wheel, 73mm turbine and our choice of either a .84 or 1.0 turbine housing. The journal bearing turbo uses a few pieces unique to KC that their team has spent countless hours developing and perfecting specific to optimizing performance of the older 7.3L Power Stroke platform.
The 7.3L uses a reverse rotation turbocharger not common on other diesel platforms, so making compressor and turbine changes isn’t as easy as there aren’t other wheel sizes and profiles readily available. Determined to bring something new and exciting to the market, the KC team looked at the technology in the BorgWarner S300 SX-E turbochargers and tried to adapt a lot of that science into reverse rotation version that could create a direct fit, stock replacement turbocharger for the 1994-1997 and 1998-2003 7.3L Ford trucks. What they’ve brought to the market is a 100% drop-in unit with the best in turbo tech for better drivability, great low end spool-up and off idle response, with the airflow and EGT control you need in a modified application.
For our particular build, their 63mm compressor wheel would move enough air to support our 205cc injectors and our low 400-horsepower goals. The 63mm wheel offers great spool-up and a broad power curve thanks to its 7×7 extended tip blade design and profile. On the backside of the turbocharger you’ll find a much different turbine wheel design compared to a factory 7.3L turbine wheel. Again, based off the BorgWarner S300 platform, KC developed a reverse rotation version in a 73mm size that would not only increase turbine flow substantially, the blade design would allow it to do so without sacrificing low end grunt and spool-up. Since we aren’t going for an all-out power house here, and the truck spends most of its time at higher elevations where the air is a bit thinner and hard to come by, we opted to run the tighter .84 a/r housing. The .84 will offer great drivability under 3000-rpms where this truck spend most of its time. We know we’ll sacrifice some top end and EGT control compared to that of a looser 1.0 a/r, but for our specific application the .84 was the better choice.
To get the maximum potential out of this new turbocharger, we also opted to install a few other supporting products from KC Turbos like their Non-EBPV turbo pedestal and high flow turbine outlet. Since our factory pedestal has been leaking oil from the Warm Up Valve rod, this was the perfect time to eliminate that problematic system from the truck all together. This offers two benefits. First, we’ll eliminate that pesky oil leak. Second, we can remove the restrictive warm up butterfly valve from the exhaust outlet and free up the exhaust to help bring exhaust temps down some more.
Riff Raff Up-pipes
While we’re on the subject of exhaust, we need to also replace our factory up-pipes that connect our exhaust manifolds to the turbine inlet of the turbocharger. The factory Ford design leaves a lot to be desired and uses a simple crush donut to seal the pipes to the turbine collector. These crush donuts have been known as a bit of a problem area for the 7.3L and leak substantially in most trucks, especially high mileage trucks like ours. We knew ours were leaking when we purchased the truck, so swapping them out while doing the turbocharger upgrade was a no brainer.
Riff Raff Diesel is another great shop that focuses primarily on the Power Stroke platforms and has really put a lot of effort in to making products that not just resolve factory issues, but improve performance or efficiency while they’re at it. Their bellowed up-pipe kits for the 7.3L were designed to replace the donut gasket with a better performing design that fits like OEM pieces would. They are built right here in the USA using aircraft grade 321 Stainless Steel, ensuring they’ll never rust or crack. By incorporating a bellow into the pipe, you’ll still get the flex and expansion needed in the up-pipe with continuous heat cycles, while keeping a leak free seal.
While the end results have been proven to worth every bit of work that had to go in to this installation, we fell it needs to be expressed just how hard a turbo swap can be on this 94-97 7.3L truck. Whether it be the lack of accessibility to some of the bolts or 200+ thousands miles of driving on it all, removing the factory turbo and up-pipes is not a job for the faint of heart. On a scale of 1-5 wrenches, this is most definitely a 5, and the toughest job we’ve done on this truck to date. It will take some specialty sockets to get to the turbine inlet hardware and an extreme amount of patience. If you have hesitations, don’t shy away from asking a local shop with previous experience making this swap for you. Again, with all that said, after driving and towing with the truck, we are very glad we went through with it.
After the install was complete and we were able to use KC Turbos nifty boost leak detector to ensure the system was sealed up tight we made our first drive around town and we’re blown away at the responsiveness of this 63/73 turbocharger. While it’s quite a bit larger than the stock turbo, with the exhaust leaks sealed up and the .84 a/r exhaust housing, the turbo makes boost effortlessly. Whether we’re leaving a stop light or rolling into the throttle when cruising, boost comes up easy and really limits smoke output of the exhaust. The power band feels wider and making close to 40-psi it pulls extremely hard when accelerating. We’ve seen over a 200-degree drop in our EGT’s at wide open throttle and towing our travel trailer has become effortless. The truck feels stronger, is more predictable to drive because there is power everywhere, and all our smoke has been cleaned up, even in our large race tune.
With a quick trip over to Edge Products to get some dyno results on the new setup, we were so happy to see 378hp and 778tq in our tow tune from A&A Design. The power and torque curve is extremely flat and explains why it feels so strong pulling our trailer. In our max effort tuning, the truck is well over 400-horspower which was exactly where we were hoping to be with this build. This old Ford is pretty much the total package now. It’s got that classic nostalgic Old Body Style Ford look with the horsepower to keep up with a brand new 6.7L Power Stroke going down the highway. With only a few more parts to install, we’re extremely happy and impressed with how this build has turned out and it honestly gets compliments and looks everywhere we take it. Anyone that loves diesel trucks has some kind of a connection to an OBS Ford and it’s a truck that will just always be a classic.
Riff Raff Diesel