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      03-30-2009, 10:33 PM   #6
KeithLM
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Drives: Crimson/Coral 135i
Join Date: Apr 2008
Location: Wylie, TX

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Catted Downpipes

There's a long thread about this. Suffice it to say by design or manufacturing problem, mine were situated such that the bung holes for the pre-cat O2 sensors were too close to each other and the sensors made contact with one another. The first shop, COBB Tuning, followed Riss's instructions and also called them. According to Riss they didn't call enough. But guess what, these people charge by the hour. What exactly should they do? Leave it on the lift, keep monkeying with it for hours on end waiting for the guys from Riss to get somewhere to check their e-mail? I can't afford that. When they had the pipes in place they could not insert both O2 sensors. No twisting, rotating, squeezing, etc. was going to make a significant difference in this.





The second shop, Stett Performance, installed them by inserting the O2 sensors in the pipes then placed the pipes in the brackets. This worked and left a few thousands of an inch between the sensors. This was not consistent with prior installations they had done using Riss downpipes. If anybody can explain how my car could be made different such that the pipes could fit in the mounting brackets and line up next to each other as expected, but have the O2 sensors be mounted several degrees off from where they belong, I'd love to hear it.

The end result is one O2 sensor was damaged, and I've spent a lot of money on labor. The downpipes did give me some additional power, and I liked the sound, but dealing with Riss was not worth it, so I finally removed the pipes and sent them back. Riss was willing to spend $400+ and provide a new O2 sensor to have this problem fixed, which tells me that they recognize the problem was on their end, no matter how hard they tried to blame others (and Anthony even called COBB incompetent at one point). Either they very poorly designed these, or something happened in manufacturing. Even if it is their design, they should have blamed the manufacturer, fixed the problem, and offered to send new pipes out ASAP.

***Update 4/9/09***
Turns out both O2 sensors were damaged, quite likely because thermal expansion caused them to push into one another.

Last edited by KeithLM; 04-09-2009 at 10:49 AM.. Reason: Update on O2 sensors
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