After ditching the Lotus T/C engines in our home built Ford Escort racers and fitting 12A Rotaries, the first meeting for the modified car was the 1979 Australian Sports Sedan championship with the event run in Melbourne in conjunction with the Australian GP. This was also the first long run for the car in its new guise. And after the first official practice we were in trouble again. This time it was noise.
Racing regulations limited the noise (in those days) to 110 decibels, and it turned out that I was pumping out much more than that. It was so bad that the track and flag marshals were complaining. Even though I had fitted a large muffler, molten fiberglass was seen dripping from the tail pipe at the end of the session, and sound muffling was zero. I did say that the exhaust gas temperatures were somewhat higher than I has experienced before! They were also higher than the muffler manufacturer had experienced before.
We were 2000 km from home, what could we do? I decided on a two-pronged approach. While the crew fitted a new muffler to the car, I went into town and purchased several pairs of ear plug defenders which I then took to every flag point around the circuit. The car might have had a new muffler, but I knew it wouldn’t last the distance. I was sort of apologizing in advance. But whatthehell, I could at least get a start!
Many years later, I was running a Datsun 510 in the Australian 2 liter Sports Sedan Six Hour being held outside Sydney, New South Wales. Once again we had both pipe and noise problems. We had lowered the car so much that we could not bring the pipe over the rear axles, and it was too low to bring it under the axles. Easy fix – bring the pipe out under the rear door, but again the clearance was such that we would grind the pipe, eventually ripping it off, after spirited cornering. The answer was to saw the end of the tailpipe parallel with the ground so we were pumping the exhaust gas directly on to the bitumen. Looked a bit weird, but it worked and also lowered the decibels that could be detected by the sound pressure meter at the side of the track! “Feathering” the accelerator past the monitor, also helped.
Exhaust pipes on race cars are always a problem.
