cntlaw

My car rolled over a pavement at an angle which had bended the front portion of the catalytic converter slightly.
As tested by the dealer, toraque degradation was not noticable.
However, based on theory, if the diameter of the pipe is narrowed, performance should be impact.

Now , my main question:-

1. Do you think I need to replace the pipe as I want my car to be perfect looking even it is the bottom part?

2. As the bended pipe is part of the catalytic converter , so the job means the catalytic converter needs to be replaced. The catalytic converter is a special one for AMG and need to be ordered. Now, my worry is the local expertise on replacement as they told me they need to set the data to the central ECU , I dont' know what that mean, but I have a feeling that if this
replacement is not done properly, there will be an adverse effect?

Please help and give me detailed advice , appreciated.!

V12Godspeed

I guess it is not covered by warranty, If i were you I would take it to the dealer. Remeber you want the best for your AMG. At least that is how i feel about my car and it is not even new.

cntlaw

Thanks. actually the photos was taken by the MB service center, I will not give an AMG car to another hand.
Yes, no warranty, it is two pipes bended , so the cost will be ~5-6K! And this is why I want to get expert advice whether it is any adverse effect if not replaced or any issues after the replacement.

I am doubt the performance degradation is noticable as the bended portion is very slightly , say 3mm, may be....I have yet to test its limit

TECHNICIAN

Its fine. Won't hurt anything

gsrthomas

I would just leave it. It doesnt seem to be bent that bad. I would not pay $6k to replace that.

SLK55R

I'm no expert .. but it doesn't look bad at all. If it is and you just can't have any imperfections ... you might want to think about replacing those SUPER expensive AMG cats with highflow cats. Might as well get a few more hp while your at it!

Moviela

I would not be too quick to change both kitty-cats, just to get rid of the little bit of rash on the exhaust pipe. They are not exactly decorative to start off. I think I would just have the rash area buffed to make it look nice, and be done.

I peeked under my wagon, and found that after the kitty-cats, the two exhaust pipes combine into a single pipe to run to the rear mufler assemblies. Since the full diameter of both pipes are not needed, I doubt the little dent in the stainless steel would make any difference in performance at all.

I can't imagine why the ECU (engine control unit) would need to be adjusted. If they replaced all four oxygen sensors, they might want to calibrate the emmission system. Your sensors look fine in the photo, and you probably have not received any messages in the MFD(multi-function display) about a problem either. There is nothing about it in the exhaust system replacement section of the WIS (workshop information system.)

I would sleep very well with that small rash on my exhaust pipe, but if you can't, don't just toss the old kitty-cats in the dust bin. DaimlerChrysler has an exchange price for them, and you can save a considerable amount of HK$ because of the precious metals in the converters that they can recycle.

I would not change a thing because: 不事关!

cntlaw

Moviela,

Thanks for this great help! (And you actually checked your exhaust too)

The MB service center told me it is 'normal' too.

I pushed the car today and did not seem to feel anything abnormal about performance ( or I would not know as I never timed my speed)

There have been no error messages. You are right, I did not mean the ECU, yes, they told me , are the senors which they need to "re-feed the data" - "calibration" as you said!

Actually, the long story was, right after the accident happened, I found the bottom of the car was making rubbing noise when I was going slight downhill, and no noise when it was flat or uphill. So I got MB service center towed it away the next morning. And, they found out the noise was because the pipes dislocated and went into the deeper bottom and the heat insulation materials had touched the shaft or some moving mechanicals underneath. So, after they reajusted the dislocated pipes, they then fixed the rubbing noise issue.

And, yes, I will check if a car beauty shop can rub that white rash off, I guess the white rash are actually the pavement's substance color?

Agreed. I won't spend that $usd5K for replacing two pieces metals nobody knows. That's will surely ease my sleepless nights!

Thank you guys, this is a great and helpful forum.