Thread: Exhaust valves
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Old 10-17-2015, 04:35 PM   #3 (permalink)
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Or you can use in-cylinder pressure sensors.

Originally Posted by aerohead View Post
At least one production motorcycle incorporated a 'smart' muffler which had a computer-controlled butterfly valve inside.
The motorcycle engine underwent a full-spectrum dynamometer test to evaluate it's best performance at all rpm's as a function of exhaust back-pressure,then a look-up menu was burned into the ROM chip which allowed the computer to modulate a servo motor linked to the muffler's valve; enabling the engine to always remain in the sweet-spot.
If you've got a loose $100,000 you want to throw at a chassis dyno,you'd be able to do this to your car.
For roughly 10,000 USD, you can purchase an array of pressure sensing spark plugs and the attendant data logging. A set of well thought out acceleration runs will get you most of what you desire.

If you are doing a single cylinder engine, you can purchase the sensing spark plug for about $1K and cludge your own data logger using slower commonly available electronics and do multiple cycle overlays.

But, that's just what I would do.
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