What can you do to make an engine sound weird?

[Ducaire]

Is there anything you can do to an engine to make it wound weird? And I don't mean louder. I've seen all these kids riding around the mall with their 327's and 350's, and while they all sound the same. If I had a 350, would there be anything I could do to make it sound completely different? (besides making it quiet...)

[MrPbody]

How crazy do yu want to get? In the '80s, BGN cars ran what was called a "180 degree flat crankshaft". The V8 sounded more like two four cylinders at war. The crank, camming, ignition and other attachments would not be cheap... But it would sound more like a ricer than a real car... Is that what you're after?

[molhannah]

Just add a gear driven timing set up to replace your chain, and they will hear you coming!!!!!1

[curtis73]

It depends on the engine and layout, but one of the weirdest I ever heard was one that used a HUGE exhaust back to the muffler. It was a friend of mine who built two flat mufflers in metal shop in high school. He had a nova with a 383. Off the headers, he built two 1" x 14" rectangular boxes that measured about 3 feet long. He had planned on lowering the car and hopping up the engine. He wanted the flow area of a 3" dual exhaust without the ground clearance issues. There are obvious flow patterns that will affect torque production, but and exhaust sound is based on pulses and how they exit the tailpipe. He basically made a huge chamber where the pulses more or less died, and the resulting flow out the tailpipe was remarkably smooth.

Other ways to make things sound interesting:

1) widen the LSA of your cam choice. Less overlap makes interesting sounds. Most cams are in the 106 to 110 degree overlap. Experiment with a 114 degree or more camshaft.

2) Starting at the end of the tailpipe, use a 1/4" drill bit to drill holes in the tailpipe; do them at 1", 2", 4", 8", 16" etc by multiples of 2 until you get to the muffler. The sound should change significantly. Start experimenting by covering differnt holes. Basically, your exhaust is like a Clarinet or Flute. It creates resonances based on its length. Venting exhaust and covering holes is like the different keys on the instrument. You'll accentuate different frequencies in the exhaust.

3) Add weights to the exhaust tubing. Sounds odd, doesn't it? Part of what makes the exhaust sound is not only the exhaust gasses and how they react inside the tubing, but how the tubing itself vibrates. This is a thing that I recommend for folks experiencing a drone inside their cars. Often times the drone is created from the vibration of the tubing itself. Adding weight to the exhaust slows its resonant frequency to the point where the drone would happen at an RPM lower than idle. If you add weight to the right spots on the exhaust, you can mildly change its sound.

4) Use one runner for each cylinder. If you have headers, cut the collector off and run 8 small tubes back to the muffler. The individual pulses will retain more of their energy and make a more even sound out the tailpipe instead of the standard "glub glub" you get from normal V8s.