Saturday, March 21, 2015

So I went to the track, and found these exhaust mods I've never seen before. What the hell?




Ok... why? The top and bottom cars use hardware store ducting.... for the easy redirection of the exhaust... but why?

The general consensus is that the exhaust noise is directed away from the sound monitoring device on the track so that the cars that are too loud to race squeak by without getting tossed out of competition for exceeding the dB limit.

Jack confirms it's to cheat the noise limit of 93dB, he was there this weekend

Thanks to all of you that commented!
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11 comments:

  1. Dan3:24 AM

    I would hazard a guess that its due to noise restrictions. The test are often "2m behind centre of vehicle" or similar

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    1. Jesse9:47 AM

      I never thought of that! Thanks! I think you have it, noise limit

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  2. Racekar6:42 AM

    There are noise restrictions at some tracks, pointing the exhaust away from the sound meter sometimes lets you squeak by if you're close to the limit. I ran an RX-7 and I always was close on sound so I knew where every track kept their sound meter and which way to point the exhaust.

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    1. Jesse9:48 AM

      I think you nailed it, there is a meter checking for legality of the cars per the rules, and this mod must be to direct the noise away from the meter, thanks!

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  3. golden geese news7:42 AM

    I'm just going to guess here: These cars have license plates, which suggests that they are both usually street legal and are able to pass any emission standards in their area. Once at the track, the owners modify their cars for racing. They remove the catalytic converters, and enrich the fuel mixtures. This would explain the soot on the bumper of the Subaru. Installing the elbows would prevent the soot deposits. Sure looks funny though. .

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    1. Jesse9:49 AM

      Could be, but some others made a good case for it being a way to cheat on the noise the cars make being directed away from the meter on the track. Thanks for commenting!

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  4. Lou8:36 AM

    These guys race on a left turn track and the exhaust is used to help keep the rear of the car from sliding out?

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    1. Jesse9:46 AM

      no, this is autocross, and they have a mix of left and right turns... but thanks for commenting!

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    2. jsfury11:29 AM

      Lou, that's funny. Jesse's right though, it's auto cross. I like the improvising of exhaust pipe. Stove pipe elbows. Brilliant! Not to mention cheap. ;)

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  5. Unknown11:11 AM

    I was a competitor at this event. These mods serve one purpose only -- to avoid breaking the event's 93 dbA noise limit. No other purpose to them. :)

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    1. Jesse12:22 PM

      Thanks Jack! great weather this weekend for it! I appreciate you verifying out theory!

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