Adventures with Scorpion drone / boom - Alfa Romeo Forum
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Status: I wonder what will happen if I press this........
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Adventures with Scorpion drone / boom

After fitting my Scorpion about a month ago I have been desperate to improve it and make it into the exhaust I hoped it was.

When its cold it is great, consistent sound through the rev range giving a great but not overpowering growl, perfect. However when its warmed up it turns into a chav pipe, at tickover and anything up to 2500rpm it just booms at you, the sound of the V6 is lost beneath an annoying drone and when driving around town its just horrible inside the car. All this makes it sound odd when you put your foot down, because its so loud at low revs when you start making progress it seems to get quieter, pretty much the opposite of what most people want.

So having bought it and having no money to try something different I started searching for a solution. What I found was the quarter wave pipe, a simple capped pipe tuned to fire destructive sound waves back into the exhaust and so cancelling out certain frequencies. You find the calculations on the net but basically to defeat the drone at 2000rpm on a V6 you need a pipe of 33" on a tee to the main exhaust pipe. So over Easter weekend I had a go at making something in true ghetto engineering style.

What I ended up with was a loop that sits on the top of the Scorpion back box but which is completely hidden when on the car. I wrapped it to cover my dubious welding and its beenon the car for the last week.

The result is pretty good, the drone at 2000rpm has now gone and the effect actually extends from around 1500 - 2500rpm where the exhaust returns to its normal tone, and I now have the exhaust I wanted in the first place. Tickover is still pretty loud but not as bad and now it gets louder when higher up the rev range just where you want it.

This is what it looks like if anyone else wants to have a go.
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Wow, good going! I'm reading vizzards building horsepower book any fair play on making that work. Complex stuff, exhausts, aren't they????
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That is a great bit of DIY. I have a QWT for my wizard exhaust and I was similarly surprised at how effective it was.
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