November 2019

BY Frank Massey I t’s not often you get two bites of the same cherry, but in my case, it happened just one week apart. The story begins many months ago with one of our regular customers. The customer in question is a real enthusiast and a keen track day driver. His car of choice is a Volkswagen Golf R. Having modified the car over several months, we now have a 500 BHP-plus Golf. It has KW variant 3 suspension with Eibach roll bars, a floating brake disc upgrade, and lightened shell, roll cage etc. It also employs a MBQ electronics platform. I could continue but I think you get the idea. It’s fully fettled, but even with the best kit and care, you are bound to have something go wrong eventually. Can you guess what happened? That’s right, a problem occurred! Lack of power delivery During a track session the car suffered a lack of power delivery, with no abnormal symptoms, misfire, oil consumption noise or vibration. The Initial investigation began with a serial scan with no DTS present. It is at this point a diagnostic strategy should be put in place. The phrase ‘first look’ involves the principle of gathering as much information without intrusion as possible. Where to start and which option to take depends very much on the symptoms. In my case the initial tests were conducted in my absence. A full load data log indicated a specified and request turbo boost pressure of 2.8 bar absolute, with an actual value of 2.3 bar indicated. These values will no doubt illustrate the level of modifications to the power train. The car still delivered a powerful drive experience although the actual power experienced was less than expected. Well-established test process This is a common problem and with a well-established test process. The charge pressure circuit was pressure tested without any external leaks. Because the en888 engine does not employ an EGR valve, we did not believe that the cause could be the result of internal leaks. Our first idea actually pointed towards the hybrid turbo, which we initially suspected as the prime cause of the ailment. I was asked to call into the workshop to review the results so far. I suggested a NVH in cylinder profile be 28 AFTERMARKET NOVEMBER 2019 TECHNICAL www.aftermarketonline.net PAR FOR THE COURSE: VW GOLF R MYSTERY, PART ONE A lack of power on hard-driven but well-cared for track day Golf R causes some head-scratching for Frank. Can he get to the bottom of it? Above: Normal valve pocket profiles