Muscle Mustangs & Fast Fords
Ford Stock-Block Stroker Engine Swap Part 2
Dyno Testing Our Home-Built EFI 331 Stroker Is Only The First Stage For This Affordable Small-Block.
In the May '09 issue, we brought you Part 1 of our home-built stroker small-block Ford engine. Within the story, we detailed the brand new Fast As Cast Trick Flow cylinder heads we were using, along with the other Trick Flow components that adorned our Competition Products stock-block-based stroker motor. This month, we're finishing off the engine with some fuel and induction parts, and we're taking it to the engine dynamometer to flog it.
MM&FF has done its fair share of testing on both engine and chassis dynamometers, and for this build, we plan to do both to accurately determine the drivetrain loss after dropping the small-block in a Mustang coupe. The engine dyno results will also provide us with optimal information for choosing the correct torque converter for the car. Knowing the torque curve and the rpm range of the engine will help us dial in the converter choice for the best on-track performance.
To refresh your memory--or to introduce you to our mule--we recently screwed together a 331ci small-block stroker engine using a stock 5.0L block, as well as a forged rotating assembly from Competition Products. The components included in the kit allowed us to drop in a bored and stroked combination without the need for the block modifications that most stroker assemblies require. Topping off our seasoned short-block is a pair of Trick Flow Specialties new Fast As Cast 190cc aluminum cylinder heads, along with a Trick Flow R-Series intake manifold and a Trick Flow Stage II hydraulic roller camshaft.
Being that this engine will largely see duty at the track, we would have liked to have gone bigger on the cam, especially given the airflow potential of the Fast As Cast heads, but we were limited by the conventional valve reliefs in the pistons, which shorten up the ever-so-important piston-to-valve clearance. Down the road, we may swap out the pistons for a set of Trick Flow-specific pieces, but we'll have to look at our ultimate goal for the engine. If we go with a power adder, we may reach the limit of the stock block before we need to go with a more aggressive cam profile.
After completing the assembly of our stroker, there were a few items that we needed to finish the assembly and ready it for dyno testing. A call to Trick Flow Specialties netted us one of the company's TFX EFI fuel-rail kits, which includes billet-aluminum fuel rails, an adjustable fuel-pressure regulator, several AN aluminum fittings, as well as several lengths of braided stainless-steel fuel line. The kit (PN TFS-51580001) retails for $543.95 through Summit Racing Equipment.
To feed those heavy-duty fuel rails, we called up the fuel experts at Aeromotive and ordered one of the company's A1000 electric fuel pumps, along with a pair of inline fuel filters. The A1000 pump can flow 600 lb/hr of fuel and is rated for 1,300 normally aspirated horsepower, or 1,000 hp when used on a forced-induction combination. We plan to use the A1000 setup on future engine dyno tests at the Horsepower by Hedrick dynamometer facility.
Mark Hedrick, proprietor of Horsepower By Hedrick in Jacksonville, Florida, has been turning out high-performance racing engines for his word-of-mouth customer base for over 37 years. After turning a successful machining and engine-assembly side business into a full-time enterprise, Hedrick now caters to hardcore racers, boaters, and the occasional street-machine enthusiast. In addition to machining and assembly, Hedrick also offers dynamometer testing and tuning at his Jacksonville facility, and it's there that we set about testing our home-built small-block Ford engine.
Between the two testing methods, most MM&FF readers will no doubt be more familiar with the chassis dynamometer. These proliferate many high-performance shops across the country and beyond, and provide performance data and tuning information with relative ease and speed.
One of the great features of the chassis dyno is how easy it is to park a vehicle on it, strap it down, and get to testing. This takes all of about 15 minutes. The biggest problem with the chassis dyno is that it can't give you an accurate measurement of how the engine alone is performing, because the transmission, rear axle, and tires create friction and resistance that robs power and torque from the engine before it's converted by the dynamometer's computer program. There are percentage estimates that we use in the industry, but they are only estimates. As power increases, there will always be greater driveline friction, and thus, a greater percentage of loss. So, in short, there is no uniform percentage of loss. Nevertheless, we plan to do both types of testing with this engine.