Often, what makes something a success can not be identified as a single element. It is usually a combination of events or circumstances that produce either failure or success. The same holds true when building engines. Two engines can look almost identical on paper but produce a huge variation in specific output. Under examination, there may not be any striking difference that would have you proclaim, "That is where the horsepower is." Yet there is no denying that a huge deficit exists in the lesser power plant.
Turning the clock back a little more than one year now, GMHTP, RaceKrafters Automotive Machine, and the author embarked on a journey that would apply the latest in technology to what would now be considered by many an antiquated engine, a TPI 355ci small-block. The impetus for this exercise was the affordability and history the TPI 350 brought to the table. The cars are attractive, and don't look dated (Third Generation F-Body and C4), the parts are relatively inexpensive, and the technology is simple by today's standards. In addition, the GM performance limelight was stolen by first the LT1 and then the stunning LS1 and later series of engines. No one can deny that a 400 hp, 400 ft-lbs of torque LS2 is a sweet piece, especially when it is produced by a displacement only a touch larger than the TPI's 350 cubic inches. The question posed and the basis of the exercise was, can an old dog run with the new kid on the block?
As explored in Part I of this series, the TPI 350 had a lot going against it when compared to the newer generation small-blocks' airflow capacity. Being a torque-biased design, horsepower was never a TPI forte. Large amounts of torque were its hallmark. Could RaceKrafters produce results with a 355 TPI engine that would gain the respect and attention of GMHTP's audience? That question was answered on Saturday, July 8, 2006, at 4:03 PM.
On the pumpNever in the author's career has the combination of high-quality machine work and assembly procedures along with the proper mix of parts ended up disappointing. The only question was how happy you would be at the end of a dyno session. Though there are computer simulation software programs to predict power produced by an engine, and even a rudimentary equation (airflow @ 28 in. H2O X 0.257 X # cylinders = power), you never really know what you have until the water brake loads it. A good, educated guess comes close to the power produced, but the real deal is what spits out of the dyno printer.
RaceKrafters has one of the...
RaceKrafters has one of the best dyno cells in the country and Bob Wise is an expert EFI tuner. The shop's equipment and Bob's "Guru" status meant the 355 was dialed-in for peak power in no time at all.
The ACCEL/DFI system performed...
The ACCEL/DFI system performed flawlessly and was much easier to work with than a factory design that would have forced a chip reburn for every tuning change.