This may be a little noob, but... I put a megan cat-back on my 2006 WRX. I'm curious whether by doing that I deleleted one of my cats. I still have my stock exhaust but I'm not sure whether the thing inline on the stock mid pipe is a cat or just a resonator. So how many and where are the cats on a stock 06 wrx? (I know there are only 2 now, the one on the up pipe is gone now) And I know there's not a for certain on this but how could this effect emissions if one cat has been lost? Any input is appreciated as always!
You have a cat in your downpipe and a cat in your midpipe. From what I understand, (haven't had my emissions checked yet) as long as you don't have any check engine lights, you should be fine. People have had their emissions checked with no cats on the car, and passed. It all depends on if the place you go to does a visual inspection, and if so, that they actually know what they are supposed to be looking for.
A cat-back by definition is "from the cat(s) back", meaning it goes AFTER the catalytic converters. You still have both cats. By the way, some confusion stems from 'downpipe' and 'midpipe': most aftermarket downpipes replace the stock down- AND midpipes.
^^ Agreed. If you just did a cat-back system, you still have both cats. The dp is a shorty with 1 cat and the mid-pipe (which connects the shorty dp to the catback system) has 1 in it as well.
http://www.filtsai.com/sti/wrx-intake-exhaust-diagram.gif Become one with the diagram. The STi and 06+ WRX are a little different since they don't have the cat in the uppipe.
Hey bud, get a catless mid pipe from Prodrive ( $149.00 ) this pipe connects the down pipe to the center pipe. Big difference. Prodrive saw 15HP just with this catless pipe alone. WILL NOT THROUGH A CHECK ENGINE LIGHT ! yayyyyyy ! The order is: Down Pipe - cat Mid pipe - cat Center pipe - resonator Muffler - ssh: My 1st mod on my car was the catless midpipe. The RPM's fly up compared to before. Much faster RPM's. Good mod.
^^^That is not guaranteed. It all depends on the individual car. Some will throw a CEL some won't. I was one of the lucky few whole replaced the entire exhaust,up, down, mid, and axle back, all catless, and never threw a CEL. Drove for anywhere between 500 to 1000 miles before getting tuned and never saw a CEL. Alot of people on here remove a single cat, and throw a CEL. Now, since Keegan has an 06, he won't have to get Emissions checked for 3 years, so even if he does throw a CEL, no big deal, he will have plenty of time to save up for a tune, or do a Mechanical or Electrical fix to take care of it.
The catless midpipe is a nice and easy install, but if you want to keep one cat I'd probably recommend going with a shorty downpipe since the factory downpipe has some nasty bends and kinks that restrict flow quite a bit.