Quote:
Originally Posted by Wonderboy
Thanks Chris,
The cat I have is from a CRX, and it actually looks like a stock one (long slender style vs. universal looking short and fat). A curved downpipe would extend from the manifold, head down and curve rearward, then termiante at a flange. That flange is where my cat would be if I were not to move it, but I don't think I've got much choice in the matter since I'm sure as hell not going to go buy a new cat if I don't need one. This is why I ask where I should place the o2 sensor (if there is indeed one at all): High up near the manifold, or back just before the cat.
What do you mean by this?
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Some catalytic converters have an AIR injection pump input on them. If the XFi has an air pump, you'd have to drill the exhaust down pipe and weld a tube for that air hose to pump fresh air into the exhaust (helps the catalytic reaction).
The O2 sensor should be close to the engine at the termination of all the cylinders, for best accuracy. Right at the top flange of the downpipe would be best. Even if you don't have one, it might be worth it to invest in a wideband if you ever plan on tweaking the engine's fuel input or trying to go lean-burn.
There are 2 stock CRX cats. The one you have is the one that can easily be replaced with a "test" pipe, that installs aft of the downpipe, near the rear forward cross member/steering rack. The other installs as part of the exhaust manifold, directly in front of the engine. The one you have will make it easier to keep the OE location of the cat (emissions law) when it comes time to make adjustments to the exhaust system for the new engine.
The CRX's stock exhaust is probably a bit large for the XFi engine, FYI. Likely won't make a notable difference, but it's just "one of those things".