Part 1
It's Possible that the Pro Stock title may be a tad presumptuous, as the '88 5.0 Mustang used for this test was a whole lot less Pro and a whole lot more stock, but we were hoping to change that in the near future. Sure, we'd never get this old Pony to run like a real Pro Stocker, but we could sure take the stock and make it rock. We've performed many 5.0 buildups in the past, and every one of them was a learning lesson on which parts and combinations work well together. With the veritable avalanche of performance parts available for the 5.0, the difficulty comes not in finding parts, but wading through the vast array.
Should we go all motor, or how about a little squeeze? Blowers are always good, especially if we combine the boost with extra displacement via a stroker combination. While all of these combinations have strengths and weaknesses, in the end, this 5.0 got a turbo.
After deciding that the boost would come from a turbo kit, we still had plenty of decisions to make. Having had excellent results in the many tests run with HP Performance in the past, we decided to take the company up on its offer to supply one of its single-turbo kits for the 5.0 Mustang. Simple and effective, the standard kit featured a 60mm turbo that offered plenty of boost and power potential. In fact, even the base 60mm turbo offered much more power than the stock (high-mileage) motor could ever hope to harness. We'll take care of that situation in Part 2 or 3 of this series, but for now, we wanted a simple kit that could be installed on our otherwise stock 5.0 motor and provide impressive boost and power numbers, all without hurting our not-so-precious powerplant.
Did we mention that the boost was being applied to a 5.0 motor with over 200,000 miles logged on the odometer? It was still in decent shape, but how long could we expect a motor like this to live? If it gave up the ghost during the first dyno run, we'd certainly understand. It had lived a long life and provided untold smiles during those many hard quarter-mile runs. That it continued to soldier on was a testament to the original design and proof positive that the legendary status of the 5.0 was well deserved.
Our idea behind this 5.0 turbo story is to demonstrate just how much power the bone-stock motor would take. If all went well, we'd baseline the normally aspirated motor, add the turbo kit, and run up the boost to a reasonable level. Then, we hoped to take the car out for some dragstrip runs to see just how the improvements in the power curve translated into changes in the e.t. and trap speed.
While you'd think every last 5.0 in existence has already been modified, it might surprise you how many people left their motors completely stock. Besides, running boost to the stock motor would allow us to demonstrate the power gains offered not only on the stock motor, but to later illustrate how heads, cam, and intake affect the power curve of a turbo motor. Would the gains be more or less than on a normally aspirated combination? Would the stock (high-mileage) motor withstand the extra cylinder pressure produced by the turbo kit? Questions like these are why we constantly run motors on the dyno and at the dragstrip.
The first order of business was to perform some prep work on the car. The '88 Mustang was equipped with a stock 5.0 motor. Being an '88 non-California car, the 5.0 was not equipped with a mass air meter. Knowing the turbo combination would certainly require tuning for proper operation, we put a mass air meter upgrade on the to-do list. Sure, we could add an FMU and adjust the static fuel pressure, but that old-school technique has some serious issues, from both a performance and safety standpoint. Adding the mass air upgrade allowed the guys at HP Performance to dial in the air/fuel and timing curves via SCT software.
The stock 5.0 motor has long...
The stock 5.0 motor has long since been replaced by the modern modular, but add boost to even a stock motor and things start to happen real quick.
The first step in the installation...
The first step in the installation of the turbo was to remove the air intake. Note the trick, carbon-fiber air intake tube. It was almost too pretty for the 200,000-mile stocker.
Next came the factory upper...
Next came the factory upper H.O. intake manifold.
Removing the upper intake...
Removing the upper intake provided access to the injectors. The factory 19-pound injectors were woefully inadequate for the turbocharged 5.0 and were replaced by a set of 42-pounders.
To install the turbo kit,...
To install the turbo kit, it was necessary to remove the stock exhaust manifolds, or in our case, the long-tube headers.
With the headers removed,...
With the headers removed, the tubular exhaust manifold was installed. Note the slick and effective thermal-barrier coating applied to all of the exhaust components.