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gizmo between exhaust and engine?


lukr
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I was changing the exhaust gaskets on my 82 brat last weekend and saw this thing between the head and the exhaust pipe and wondered what it is and what it does? I assume it has something to do with emissions. Can I chuck it when I have a new exhaust put on my brat?

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The ASV system dumps air into the exhaust to help the cat burn unburned hydrocarbons better. Aside from emissions, and maybe decreasing the exhaust temps (why that would matter I don't know), I can't see where it has any use. The only reason I'm keeping mine on is in case I have to pass IM sometime.

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The AIS is what you are looking at - blocking it off is good if you don't have to pass emissions because they can fail, and dump a whole load of plastic from the "silencer" into your carb.... not cool. Also - I ran through emissions with it both on and off, and I actually got higher readings with it enabled. You can easily disable it by disconecting the valve, and putting a quarter down in the outlet, and threading the pipe back on. It will still *look* stock too - just won't work at all. And it can't fail this way either.....

 

Also - if you have a small exhaust leak somewhere in the Y pipe, the ASV will bring in enough extra air to cause really horrible backfireing.... something I have personally expereinced, and fixed using the quarters (thanks to Qman's advise....).

 

GD

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When I Weberized my car, I disabled the AIS but left it on the car. My plan at the time was that when I needed to pass emmissions I would temporarily install a smog pump where the A/C used to be. It'd blow air into exhaust and help burn the hydrocarbons in the cat. Haven't tried it, don't know if it'll work.

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