Project TSX's aim is simple, but by no means easy: beat an M3. Trounce the Teuton with well-planned bolt-ons. Best the Kraut in handling, braking, acceleration and even styling.
In the first installment, Skunk2 screwed on its own adjustable coil-overs and short shifter, installed massive Brembos and fitted the car with 18-inch three-piece Volk wheels and BFG g-Force KD tires. The results of said footwork were great, producing handling numbers more or less on par with an M3.
It's time to motor and play dress up. In stock form, the TSX gets the best possible K-series engine combo, combining the large 2.4-liter bottom end also found in the CR-V (but with better rods) and the i-VTEC head as found in the Acura RSX Type-S. Skunk2 has probably put K-series engines through as many engine dyno pulls as anyone and knows the engine platform well.
Project TSX's stock acceleration numbers were nothing to be ashamed of, but nothing to toast to either: 15.9 seconds at 88.6 mph in the quarter mile, with a 0-to-60 time of 8.1 seconds. Project TSX started life as a press car for Acura. When Skunk2 removed the car's computer, its techs noticed it was a preproduction ECU. When Skunk2 started working on the project, Hondata had yet to come out with its K-Pro programmable ECU for the TSX, so Skunk2 rewired the car to use a K-Pro from an RSX Type-S for duty on the K24.
The TSX's engine tune from the factory is quite conservative, so Skunk2 was able to extract healthy horsepower gains across the powerband. Changes were made to intake cam timing by controlling i-VTEC, but for now, cams remain stock. Timing and fueling maps were both modified. Power was more easily extracted by modifying the fuel curve so Skunk2 focused its efforts on this part of the calibration.
The rev limit was set at 7500 rpm because, although additional horsepower could be gained by spinning the engine to 8000 rpm, big revs in combination with the K24's long, 4-inch stroke can do unkind things to rod bearings. The current ECU tune is described as "mild" to be compatible with California bilge water.
The Hondata K-Pro ECU will not drive the stock gauges, so Skunk2 went full race with a fabricated dash panel displaying rpm, water and oil temperature.
Skunk2 realized surprising horsepower gains during development of its TSX header: 9 hp with the stock cat in place. Manufactured from 304 stainless materials, the Tri-Y design uses merged collectors and features one step in diameter in the primaries. Skunk2 is also considering a race header for the TSX that deletes the catalytic converter.
Skunk2 uses the same 304 stainless material used in the headers for the exhaust. The midpipe is made from large 70mm diameter tubing coupled to dual 60mm outlets feeding into N1-style straight-through mufflers with 4-inch tips. During development, a very slight increase in horsepower was seen using slightly smaller diameter tubing, but the larger tubing will pay dividends in better power production when coupled with future modifications.