Catback Exhaust Broke My Car!

[Williampreza]

Sorry in advance for the long description, but I feel you guys need the whole story before you can help me.



As you recall, I recently replaced my OEM catback exhaust with a Corsa system. I obsessed forever about which one to go with, but I finally bit the bullet and went for it. And for the first couple weeks everything was fine, but then I started to notice something really weird happening:









Notice on the right side, there's more soot than on the left!



Well, I was not at all sure what was going on, so I took a drive (I know, I know, I shouldn't have driven the car in such condition, but I was woefully uniformed at the time.) up into the mountains to visit a good friend of mine (he's also my cousin) for a consultation.



I figured Delbert (my cousin) would know some things about what was going on, seeing as he owns a Impreza that he's got painted baby blue to look just like that 2222 car that Collen MacRay drove in the rallies. He's working on it all the time so you know he knows what he's doing.



So, anyway, Delbert told me that the problem was that the new exhaust was causing problems with my tune on the car, specifically that the right cylinders were running rich and the left cylinders were running lean. That, he said, explained why the right side had more soot, since it was releasing more hydrocarbons and such into the atmosphere.



I told him that that was crazy and he must be smoking something, but he said that he had stopped vaping three months ago when his momma hid her personal massager and he couldn't steal the batteries from it anymore. (As a side note, Delbert's little sister whispered something to me about him still being a vapist when he was out of the room later on, but she has a real bad lisp and I can't make out what she's saying half the time anyway.)



Besides that--I told him-- I don't have any money to fix something like that, not with my divorce being finalized this month and the new carbon fiber wing I ordered. But he said it wouldn't be any problem, I just needed to put some backpressure in that side of the exhaust. Since I had put in a catback exhaust, the best thing to do was to put in another cat, as that type of exhaust removes one of the two (one for each side of the engine) that are in the BRZ exhaust.



I still didn't have enough money to even do that, but he said that he knew where there were a few cats laying around that we could have. So we went to his grandmama's house (she's dead now, but there's all kinds of cool stuff still in her house that's free as long as you don't mind going in the dark and digging through the piles of newspapers.)



Anyway, we installed said cat in the right side, and, after breaking it in (god that stinks!), the problem seemed to be fixed. I raced him back down the mountain and my butt dyno said that I had probably picked up a good 5-10 hp in the process. Delbert's sister agreed, as she had volunteered to ride with me to double check our work. She even seemed hellbent on me winning the race, up to the point of insisting that I not stop, even when we got to the main road. I put her out and told her to walk back and find Delbert where he had broke down and she proceeded to take a shortcut that looked just like she was running in opposite direction. Hill folks are odd that way.



Unbeknownst to me, the new cat made things even worse. Although the right exhaust pipe stays clean now, the soot problem just migrated to the left side! I guess that side's running rich with all the extra gas it's getting because the right is probably more efficient.



Not only that, my soon-to-be-ex-wife got really angry at me when I told her how I had fixed the problem and I think she called the cops about it because they seem to be following me whenever I drive anywhere now. This is puzzling since Tennessee doesn't even check emissions on the eastern end, and you'd think they'd be happy that I added a cat.



Perhaps I did not install it correctly. As I mentioned, that new cat stunk something awful when I first drove with it, and there were weird noises too.



In the end, I've decided that I probably should have not cheaped out and that I should just get a real tune. Until then, I'm trying to keep as much weight off the right side of the car as possible. I have removed the passenger seat and, in what I consider an inspired move, removed the right rear tire in order to save unsprung weight. Unsprung weight is worth 4-5 times sprung weight for those of you that didn't know, and i get some killer burnouts running on just the rim.



I thought about the OFT, but it's also out of my price range. Plus, Delbert suggests that I not try to do a tune by myself and that I should find a reputable tuner. I know lots of you guys are familiar with what tuners are worth using so I want to know your opinion on this one:








Edit: Also, what key am I tuning to? “A” seems reasonable, but that puts my redline at nearly 7500 rpm and it’s hard to think with that much racket after an hour and a half of tuning.

Looking forward to your advice, and Happy April 1st from East Tennessee!

[dillanp86]

My buddies engine just blew with a corsa exhaust and I totally thought this thread was gonna help answer our question on what the hell happened since he was completely stock except for JDL UEL headers, OFT and corsa catback. You got me good, happy April 1st lol


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[Teseo]

2L;DR

[OND]

Perfect story. 5/7

[humfrz]

Originally Posted by Williampreza

Sorry in advance for the long description, but I feel you guys need the whole story before you can help me.



Looking forward to your advice, and Happy April 1st from East Tennessee!

Well, now, from the looks of the differences in the deposits of your tail pipes, I think the Easter bunny hid an Easter egg in the left exhaust pipe causing most of the exhaust to exit the right side.




humfrz

[tehShirt]

Corsa owner checking in, can confirm all these claims. I carry some steel wool with me every time I go to the dealer, so I can hide the lean/rich conditions from them and still retain my warranty.

[Mr.ac]

Ha!
You perfectly described vapers.

[Dr. BRZ]

You need psychiatric help...

[mav1178]

...

[idkwhatimdoing]

Two cats? I only got one installed right now, but boy is he angry about being in there


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[SCQTT]

TN has three stars in their flag, because its really three different places. In the east you have Hillbillies, in the central you have horse/county music folks and in the west you have a big ass ghetto.

I lived in the ghetto for 10 years, I'm not kidding.

At least in the east you have fun roads.