Catalytic converter replacement with Magnaflow

[claudio512]

The OE [original equipment] I.D. is required to exhaust gases same rate [Magnaflow part no. 94006]. There is no need to exceed OE specs.









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[rdcosta]

Hi,

I need to do this job shortly.

Can you provide more details on the work:

where was it done
how much were the cats
was the exhaust dropped to do the work
how were the cats aligned with the existing exhaust

etc.

Thanks for your help,

Rob

[claudio512]

First, need to remove O2 sensors to avoid heating them up [do not cut pipe to close to O2 sensor holes or you will make new holes to screw O2 sensors]; second, cut old cats using acetylene torch. You will need an additional 6” 2 ½” I.D. pipe, cut in half’s. Slide new cats into the exhaust plus pipe, use electric arc to weld new cats and pipe in place. Look at the pictures. Perhaps, there is exhaust shop in your neighborhood willing to do the job if you do not have tools for the job. [WARNING! do not use clamps to reconnect cats because it is dangerous and will leak exhaust gases, which are dangerous to anyone’s health inside the car].

Here is where to cut old cats:




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[rdcosta]

Thanks,

Know anyone in Chicago who can do it?

Rob

[claudio512]

There are few folks [shops] on Cicero... or any exhaust shop will do and all they need to know are the the parts to install, which are two Magnaflow part no. 94006. Ask for price.


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[rdcosta]

Thanks,

Did you have your car done in the Chicago area?

Rob

[claudio512]

Never... familiar by work experience.


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[claudio512]

The picture provided by Peter C. [Australia...]. To cut open a 4” grinder with 1 mm steel cutting blade was used. According to Peter, “It took a couple of minutes and very interesting to see differences between the OE and after market cat types. The OE has 3 solid ceramic brick's about 100mm (4inch) long with spacer collars between and held in place with a steel braid and wrapped with fibrous material that appears to be impregnated with granules of "Gold,” as the Magnaflow has only two ceramic bricks of 1” thickness, not sure what the precious metals are? Hoping the information answers a few questions.” Thanks mate for providing the picture and info.

G’day






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[technobuff]

I have read mutitudes of threads regarding catalytic converter replacement options for E38's but continued to be puzzled in my selection on how to move forward. Let me start first by saying, the OEM is the best option if you have the money to spend or if the vehicle is still under warranty. It was confirmed also in previous posts that oxygen sensor replacement are a must for the catalytic converter that needs replacement to avoid the "check engine light" issue. Make sure that the vehicle has no or major fault codes that would immediately send the "check engine light".

OBD I recommendation aside from the OEM: I.D. and O.D of exhaust pipe
DEC Model #
Approx. Price
Bolt on
Magnaflow Model #
Approx. Price
Cut and weld
Miller Model #
Approx. Price ?????

Best Recommendation:

OBD II recommendation aside from the OEM: I.D. and O.D of exhaust pipe

DEC Model #
Approx. Price
Bolt on
Magnaflow Model #
Approx. Price
Cut and weld
Miller Model #
Approx. Price ?????

Best Recommendation:

Can somebody populate the Model #'s, approx price, best recommendation information to assist fellow members on the best solution to move forward in terms of replacement?

Can someone also use a Oxygen Sensor bypass on the post O2 sensor to send a signal to the engine management system that everything is running fine?

[claudio512]

Indeed, O2 sensors can be by passed but it is necessary to use a jumper to dummy a working O2 to other electronic devices up stream. The best Magnaflow match is the 94006, which are 2 ½ I.D., and easily slips on exhaust without modifications. WARNING! It is necessary to use the correct I.D. to void false code errors or check engine light warnings by increasing or reducing back pressure.

OE cats are the best choice

Magnaflow 94006 cats are a good choice

Any other cat... I am not familiar.



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[vladlen1969]

Installed new Magnaflows 94006's one month ago at Meineke (700 miles) CE light came on last night. Checked the code: Cyl 5 - 8 cat deficiency and the saga continues. Nothing beats OEM.

Jim
1997 740iL
120K
Built 2/97

[technobuff]

Jim,

Did you follow Claudio's detailed instruction on the cut off points on the old CAT, the weld points and additional exhaust piping material welded to the new Magnaflow CAT? Did you install new pre-cat and post cat O2 sensors?

[technobuff]

Claudio,

How many miles have you driven using the Magnaflow 94006 cats? Did the check engine light ever lit up until now? Did you replace both cat? if the answer is no, which did you replace 1-4 or 5-8?

[vladlen1969]

All was cut and installed as described, all 4 sensors were replaced about 1 year ago or 7,000 miles..

[technobuff]

Jim,

I am having a little bit of a disconnect. How could you have known of the complete procedure if the Claudio's original post on Magnaflow 94006 replacement was dated 11/06/05?

Please clarify....

[vladlen1969]

If you search the archives this issue has come up many times before, and installation procedure was already outlined with the most suitable aftermarket cats for our purposes. The latest posts, thanks to Claudio who added pictures.

[claudio512]

Replaced both at same time 2,080 miles ago and no check engine light warning or any other error code. Car is performing great in spite of several trips to Houston and Plano, Texas [I did not see Darth in Plano...]


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[claudio512]

Which magnaflow model is on the car? It has to be similar specs cat and using other with smaller I.D. [inner diameter] means decreasing or slowing down exhaust flow. The inner diameter should be 2 1/2". How long ago did you replaced O2 sensors? What type of spark plugs are on the engine? I have over 2,000+ miles and no problems and it has been checked at inspection station and passed twice. So, provide complete details to understand problem.


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[vladlen1969]

Claudio, the cats are magnaflows 94006 with the i/o 2 1/2". All 4 O2 sensors were replaced about 8,000 miles ago. The O2 sensors were removed prior to cutting and welding process. The plugs were replaced by dealer at 100K service would assume using the Bosch OEM's. I have cleared the ce light (indicating 5-8 cat deficiency) and have driven about 400 miles since without re-occurance.

97 740iL
120K

[claudio512]

Provide details on your including type of spark plugs and fuel you are using... without details I cannot provide feedback. Also, you mentioned to have replaced O2 sensor a year ago. Here is your link: http://bimmer.roadfly.com/bmw/forums/e38/7213543-1.html




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