Cat Prices/Delete/Test Pipe???

[gcims]

Have a '98 318ti w/ m44 engine in great shape, 130K mi.

My Cat broke off from the pipe to the exhaust header and cannot be welded. Plan on keeping car for at least 3 if not 5yrs.

My mech found a good cat and pipe set for $650.

I have found some cheaper ($300-400) on line that say they will fit w/ Ltd warranties of 2-5yrs/20K-50K mi. Considering these.

Heard about bypass or test pipes to eliminate the cat but am worried about performance probs and the O2 sensors. Heard there are rigs that hook to the sensors to fix any CEL or bad data to ECU.

THE best part is I don't have to get the car tested for emissions where I live! I hope that will open up my options.

ANY advice would be appreciated. I would rather not drop another $1000 into this car but not sure what is the best option. Thanks folks!

[mohaughn]

At idle, my car is quieter without a catalytic converter. I may have lost a little low end torque, but I think it pulls better up top. At full throttle the car is considerably louder. I have a 95, so I don't have to deal with the second o2 sensor.

If you don't have a cat or some type of post cat O2 simulator, you will get a CEL. I really don't know how much the DME uses the post cat O2 for engine settings. I'm pretty sure it is just for emissions and OBII tests, and that only the pre-cat O2 sensor is used for adjusting engine tune. So, if you don't mind a CEL, I don't think a post-cat CEL will affect how the car runs.

[gcims]

thanks for the advice. We decided this am to bite the bullet and do the right cat. Hope this fixes a intermittent stutter problem we have been chasing and throwing money at for the last 4 months. thank you for your help.

[xxxJohnBoyxxx]

Post cat O2 can be tricked by just removing it out of direct exhaust stream with a extension pipe. Very easy and cheep.

Remove it. You will not loose low end torque and will gain a few HP. There will be more exhaust note without the cat but some people like that

[gcims]

John,
How long an extension we talking and what materials have you used? Welded on I assume? Have any pics you can slap up of past mod? Thanks! BTW, you ever catch the SOB that hacked your site? Been out of your loop for a while.

[xxxJohnBoyxxx]

Originally Posted by gcims

John,
How long an extension we talking and what materials have you used? Welded on I assume? Have any pics you can slap up of past mod? Thanks! BTW, you ever catch the SOB that hacked your site? Been out of your loop for a while.

I will post pictures today for you. I'm not sure if the Youtube was a hack. The person that was trying to play with my pc stopped. I think they were looking for Damos & A2L files or fully modded M5.2 firmware to steal. I have not been hit in a while but nothing was taken they probed my Wii system and got lost with the Linux server.

[xxxJohnBoyxxx]

Ok here is the way to do it cheap if you have a little room:

First buy a spark plug "anti foul" spacer here are three pictures of a old one a found in my parts box and they are found at all local auto parts stores, you want the one for a 13/16 plug:


Pic 1




Pic 2





Pic 3

[xxxJohnBoyxxx]

In picture 3 you will see a closed end that needs to be drilled out. Here is the end that need to be drilled to the O2 sensor end size:





After drilling that out you can screw in your O2 sensor into the spark plug "anti foul" adaptor and the O2 is out of the direct exhaust stream. You can see I did drill this drill but these pictures will give you reference:











Screw your O2 into the adapter and the adapter into the exhaust pipe. This will put the O2 in a shrouded position and not in the direct exhaust stream so it will read less Oxygen with no cat in there or a test pipe and the computer will think the cat is in place and working good.

That simple.

***If there is not enough room for the extention then we go to plan 2***

Let me know?