Project Obsessed

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.

KC Turbos turbocharger ford diesel
While the 94-97’ 7.3L Power Stroke was turbocharged, a lot has changed the last twenty years. With the added fuel in Project Obsessed, upgrading to an aftermarket turbo, like this 63mm stock replacement from KC Turbos and bellowed up-pipes from Riff Raff Diesel was a no brainer.
The factory turbocharger moved enough airflow to support the factory horsepower level, but as you add tuning and larger injectors, increasing airflow is key to getting the most performance and cooling from the 7.3L Power Stroke. KC Turbos recommended their latest 63mm compressor for our injector size and the trucks use as a daily driver and tow rig.

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.

The often overlooked must have upgrade for a great running 7.3 turbocharger is an upgrade to the turbine side of the turbocharger. The factory turbo uses an antiquated turbine wheel design that is extremely restrictive at these power levels, so KC Turbos develop this all new 73mm turbine wheel based off of the popular BorgWarner SX-E turbine wheel to offer the best balance between turbine flow and spool-up.
Riff Raff Diesel uses a completely different style up-pipe with an integrated bellow to allow some flex and movement with the continuous heat cycles. This style up-pipe offers much better durability and a leak free seal the factory style crush donut up-pipes can’t.

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.

Judging by the red paint on our factory unit, it is safe to assume the turbocharger has been worked on at some point, but upon inspection it was still running all factory equipment, including the stock compressor wheel and the big 1.15 a/r turbine wheel. If you’re tackling this turbo swap in your home garage, be prepared to spend some time here.
After what seemed like hours of fighting and trying to get access and tools to break loose the turbine housing bolts, the turbocharger could finally be removed as an assembly still attached to the turbo pedestal. At this point you finally have access to the up-pipes so they can be removed as well.

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.

Thanks to the soot you can see blown all over the up-pipes and the firewall, these have been leaking for quite some time. The crush donuts had failed to the point that we didn’t even need to loosen the retaining bolts, the collector slid right off. These exhaust leaks would’ve had a major effect on turbo spool-up and engine efficiency.
With the factory unit out on the bench you can see a few differences compared to the soon to be installed KC 63mm unit. The most obvious change will be that shiny new billet compressor wheel that will not only move enough air to support our 205cc injectors, but will offer great spool-up and surge protection while towing.

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.

On the exhaust side of the turbocharger, Ford used this butterfly valve as a way to warm-up the engine quicker on initial startup. By closing the valve it restricted exhaust flow to create more heat within the engine. However, the valve is a major restriction that can hurt power and EGT’s, not to mentioned how commonly they fail and create other issues. KC Turbo supplied this hi-flow outlet to free up as much power as possible.
With the compressor covers removed you can see the difference in compressor wheel design. While the factory wheel was just fine up to around 300hp, the larger 63mm billet wheel is a necessity. KC Turbos offers a handful of direct replacement units for 7.3L trucks depending on your power goals and uses including their Stock Replacement, 63mm, and a 66mm.

Labor Intensive

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.

A quick glance at the turbine side of our original turbo helped explain some of our other drivability issues and why the truck struggled so much to maintain consistent boost levels while towing at lower RPM’s. Notice the large gaps between turbine blades and the exhaust housing? This turbo was losing a lot of efficiency on the turbine side.
Found the culprit to the slow but steady oil leak we’ve been fighting for the last few months. That factory turbo pedestal was still using the warm-up valve that’s prone to failure. As you can see here, the rod used to open and close that valve has been leaking oil from within the pedestal for quite some time.
Out with the old. In with the new. Riff Raff Diesels bellowed up-pipes are a direct fit replacement for the factory crush style up-pipes and will solve all future problems with exhaust leaks. Built right here in the USA they use top quality stainless and will last forever.


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.

Time for reassembly! With the new bellowed up pipes dropped down in place, we are also installing a new up-pipe collector just for good measure. Our original collector had a couple bolts broken off in it and this was just an easy remedy to the headache.
Sitting on the new Non-EBPV pedestal supplied by KC Turbos they’re fully polished 63mm unit looks right at home on the old Power Stroke. While we opted to go with the larger 73mm turbine wheel, we did stick with a tight .84 a/r exhaust housing to offer the best spool-up and low RPM performance.
We love it when a plan comes together! That fresh turbocharger with some high-temp coating on the exhaust housing looks so good with our black wrinkle coat piping. You’d never know this was a 231,000 truck, the engine bay really came together nicely on this build.
With a quick trip over to Edge Products we were able to make one quick rip on their in-house chassis dyno. Since this truck build is all about versatility and towing performance, we think these are the real numbers to look at, this is the Tow tune A&A Design built for us. This tune is virtually smoke free and with the new turbocharger is hard pressed to get over 1200-degrees at wide open throttle. 378hp and 778-tq should be perfect for towing the long mountain grades here in Utah.

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.


KC Turbos

Riff Raff Diesel


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