Club Cobra - Sound level

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Thought I would share - have seen some sound data reported elsewhere but not sure if I have seen data for the Kirkham sidepipe system. I have the stainless headers and pipes. With the engine at idle (900 rpm) and the car stationary, I measured 94 dB at a distance of 10 ft from the side of the car, in line with the exhaust outlet, with the measurement taken at ear level (approx 5'10" above the ground). Inside the car, again at idle and with the car stationary, I measured 104 dB with the measurement taken just in front of my face at ear level. Inside the car at 3000 rpm (typical cruise speed engine rpm) and with the car stationary, I measured 112 dB, again at ear level just in front of my face. All of this data was taken on my iPad using a fee app so not a calibrated meter. Engine was under no load and as noted the car was stationary. The background ambient noise level was 55 dB. Subjectively I would say it is louder when actually moving at 80 mph or so under load at 3000 rpm vs what I measured above (112 dB) in a static no load condition.

Mike

I would think the stationary idling measurements would be pretty accurate, obviously, but the 300 RPM with no load are not realistic. You can expect a bit more noise under load on the highway, but you won't hear it as loudly as it is going off to the side and back as you move along. Other traffic and pedestrians will hear it, but you will only catch part of it, which is enough- IMO.
This is why I carry foam ear plugs in my car for longer trips where I need them. They take off just enough of the bark so you don't get overly tired of hearing the loud exhaust drone.

Bob

Agree and I plan to get an on-the-road measurement next time I have a passenger along.

I too wear the ear plugs, pretty much 100 pct of the time.

I borrowed a professional sound pressure level (SPL) meter. Secured it on the rear deck between the seats at about ear level. Was more concerned about what I experienced than those external to the car. 94dB at idle, about 1,000 rpm and 123 dB WOT at 5,000+. I've since changed muffler sections and it's louder but haven't checked. I always wear plugs for anything other than driving the 1/2 mile to get gas. I wear earplugs with my helmet if on the track.