We had the great pleasure to spend a day at Thunderhill Raceway Park with the Golden Gate Lotus Club. We drove 9 hours from Portland, OR to Willows, CA with our prototype turbocharged Lotus Elise in tow. The goal of the trip was to test our products at elevated temperatures and at racing driving conditions.
We participated in six 20 minute sessions throughout the day, for a total of 2 hours of high-speed driving. We were running our Stage 2 GT2860RS turbocharger kit that was making 300Hp at the wheels. We are also using the stock engine, transmission, and clutch. Ambient temperatures for the day topped 100 degrees F and this definitely had an effect on the vehicle. The car was not babied either. Shifting was always done at or near 8,500 RPM, and the engine spent most of the track above 5,000 RPM. The added low-end torque of the turbocharger did help to pull the car out of the occasional botched turn without the need to downshift. The stock radiator was working hard, but successfully held the coolant temp at no hotter than 205F. Intake air temperatures did climb, but ignition timing was automatically reduced to account for the hotter air. This reduces power, but also keeps the engine safe by preventing knock. Even in these extreme conditions, driveability of the car remained perfect. The power delivery was instantaneous, but always smooth and very controllable. The GT2860 is definitely a very good match for the Toyota 1.8L.
At the mid day lunch break, we removed the rear clamshell for a full inspection. Heat is a constant menace to the engine bay and we have been experimenting with different solutions. First off, we added a duct that directs fresh air from the driver-side intake vent directly to the underside of the intercooler, where an electric fan then forces it through the intercooler and out the rear deck lid. We also created an air dam to prevent hot air from the turbocharger from entering the suction zone of the electric intercooler fan. These solutions seemed to work very well, as the intercooler was not becoming heat soaked and consistently cooled the charge air by about 30 to 40 degrees. We were also experimenting with ceramic coatings. Out exhaust manifold, turbocharger, and downpipe were all treated with a thermal barrier coating designed to reduce the radiated heat. We made improvements to our stainless steel exhaust manifold heat shields and were testing those as well.
During the mid-day inspection, we were pleased to see no physical damage from the heat. All components were intact and functioning just fine. But just because nothing broke, doesnt mean that we aren't going to make any improvements. We are currently exploring other heat management devices that can control the heat even more than what we have already. Keeping the heat trapped in the exhaust system not only lowers under-hood temps, but also improves spool-up of the turbocharger.
At the end of the day, I did get the pleasure to ride shotgun with a much more experienced driver in his '05 Elise. Robert S. had no mercy on his vehicle and was able to push it around the track at an unbelievable rate. We look forward to the day when we let an experienced driver like Robert track our turbocharged Elise and push it to its full potential.
Thank you to the Golden Gate Lotus Club for holding the event and running it in a relaxed and open format. It was a fun day, and we look forward to doing it again.
