resonator/silencer removal

[moneytree]

Hi all!
I instructed my workshop to remove the resonator for the exhaust.

This is my story:

After picking up the car, I noticed the sound has improved much, definately louder at pickup, no humming noise, but at high speeds also some additional noise, although marginal,and only when exceeding 160KM/H.

Only now I noticed they have removed the 2 catalyst/filters/silencers and replaced with straight pipes INSTEAD of the resonator: the resonator is still there!

Item 1 and 2 was removed
http://www.realoem.com/bmw/showparts...90&hg=18&fg=10

my question is now

1.) I am happy with the sound, should I still opt for removing the resonator? what would be the effect of cross-mixing these two mods together? any downsides?

2.) should I ask them to re-do the catalyst mod and only do the resonator mod instead?

I noticed these two items are very expensive.

the check engine light came on and I assume it has todo with the sensors for exhaust fumes. any way to get rid of the sensor/light?

[moneytree]

pls help me out

[Weasel]

The check engine light is undoubtedly from the missing cat converters. It will be "catalytic converter efficiency, bank 1" same for bank 2. There are some aftermarket "O2 simulators" out there people use on domestic cars, but I don't know if they would work on the BMW's very strict engine programming and parameters.

What I would do is print out that page with the prices, bring it to the shop and hope for their sake they didn't sell them to the "core guys" who would give them about $120 a piece for them... Preferably have them buy you new cat converters, but more likely... weld them back in. And have them do the original job paid for. And all on their dollar as it was their costly mistake, not yours. (they probably realized by now that they removed the cats rather than the resonator, and would probably be expecting you to return anyways)

On that note, the last piece of advise is to be very nice and polite when you go back to them with this. I can tell you (most) people are A LOT more likely to help you out without problems if you are understanding and not belligerently blowing up on them. But do NOT let them crawfish out of it, it is their mistake.

[TwinsPoppa]

So ... they removed the catalytic converters?! I would have them replace them then remove what they were supposed to in the first place - the resonator.

[LI-X5]

yup have them put it back to stock and do the job they werre supposed to do !!

without the cats you may not even pass inspection !!

[Weasel]

No it wouldn't pass inspections. But He is in Malaysia, they might not have to worry about that there, we don't have emmisions tests in the greater New Orleans area either.

[Icer006]

If he's in Malaysia... anything can pass with a little bit of "incentive"

[steed77]

Where you are at, I would just install O2 extenders. The chance of that shop still having your old converters is very unlikely.

They sell adapters that move the O2's out of the main exhaust stream and will still get a reading. You may have to exterminate with the right combo.

[Weasel]

His upstream O2 sensors are still there and reading correctly, thats the ones his DME reads for fuel mixture, etc. The downstream O2 sensors are still there also and reading correctly as well, but the only task of those is to monitor the catalytic converters efficiency, for emmisions reasons.

[villajoe]

I'd leave the cats off for better flow and remove the resonators too.

I'd also try to get the cats back and sell them maybe.