For our second trip to Buttonwillow, we had a busy agenda. Shake down the new Fit-powered Piper, test some restrictors and put 500 more miles on the Fit engine. Unlike in December, the weather was perfect for testing, with a low of fifty degrees and highs in the eighties. The engine was the same as the one tested in December. It had 2,150 miles on it (270 miles from December, the rest in dyno ECU testing). As in December, we had the help of Robert Podlesni, who handled the driving chores.
Monday was spent getting Robert and the Piper set up; we ran the Goodyear 160 compounds from the first test for the shakedown. Special thanks to Dan Campbell at Vestal race cars for letting us sneak onto his set-up pad. After lunch, we were confident the car and Robert could be consistent and installed a new set of Goodyear 430 compound tires. As we attempted to get some restrictor testing in, Robert reported the fuel pressure rising, so we asked Robert to monitor it. After five more laps, he came in and said the pressure was higher, and that the engine was losing power. We decided to install another set of injectors and this cured the problem. After returning to HPD, we gave the suspect injectors to our materials lab, which confirmed we had clogged two injectors. Researching at HPD, we found debris in the fuel cell and discovered the inline filter was not the specified filter size. We informed our customer representative, Julian Macias, and he alerted our customers that we would be shipping them a new filter. With that under control, we ran some more laps and Robert reported all was well. We ended the day with 134 miles. With everything working properly, we felt confident for Day 2.
Day Two dawned bright and sunny. We installed the new tires and ran some laps to get a baseline on the 27.5 mm restrictor. After four timed laps, we installed the 28.5 mm restrictor and sent Robert back out. One-point-three seconds quicker! We added some fuel to bring it back to baseline and installed the 29.5 mm restrictor. This gained us another three-quarters of a second. Crew chief Troy McCall pointed out that the engine sounded better on up shifts, not as lethargic as with the 27.5 mm unit. Robert confirmed this, stating “the engine has come to life. The torque and top end are there now”. However, this still left us a second behind the Vestal on the day. With no more restrictors to test, we asked Robert to perform his standard marathon driving duties, which he did flawlessly. We did three 45-minute stints, followed by a 30-minute run to close the day. We ended the second day with 310 miles, and 440 total. Pretty good test.
