So today I took my car up to my local custom exhaust shop to have my magnaflow 94035 cat installed. They got me right in and started on it and it went downhill from there...

I told the guy that was to do the work on my car that I wanted to have my pacesetter header downpipe cut before the pipe size reduction at the end so I could have 2.25" from header to muffler... He said that was no problem.

They got under the car and cut the downpipe right where I wanted them to, welded in a section of 2.25" pipe to link the header to the cat. What they did on the back side of the cat is completely rediculous to me... Instead of unscrewing the 02 sensor from the stock exhaust piping and screwing it into the pre-tapped hole on the 94035, they somehow filled the pre-tapped hole on the cat with metal, sealing it permanently, welded the back of the cat to the existing (small) exhaust pipe with the O2 sensor in it and called it a day. My exhaust setup is now:



I'm pissed...

They told me they did that because with an OBDII car, the O2 sensor has to go right back where it was... They basically told me that since the pre-tapped hole was IN the cat, there would be problems... they wouldn't tell me what problems there would be, but they said that was all they could do...

my question is, if I don't feel like fighting with them too much to get them to fix the problem, how hard is it to fashion up a piece of 2.25" pipe and tap it for an O2 sensor... so I can just cut out the small part and replace it?

why not just retap the cat and weld in a 2.25 inch in after the cat to make it all 2.25

Is that possible to just re-tap that area they filled with metal?

man they are totally lying to your face thats the saddest thing i have ever seen u can get sensor bungs that can be welded right into the side of any pipe any shop should have them and make them fix it for free u payed them to make your car faster not slower and u could have done without them feeding u a face full of bs go back there and make a stink and don't leave until its done the way u want it and don't wait in the waiting room go stand right beside the guy and watch him do it so its done right because never mind the fact the pipe wedges down u can be sure the guy stuck the 2'' pipe inside of the 2.25'' and just welded it up so now u have a super restrictive edge before it wedges down u worked hard for your money don't let loosers take it from u

i just get a 2 1/4" pipe put in and have the o2 put in the 2 1/4" pipe


the o2 doesnt need to be in the cat , the 1 bad thing is your gonna loose the flange after the cat unless they have 1 that is 2 1/4"id


but it does mean 1 less gasket to leak

Well, Eric, thats not too much of a problem cuz i now have NO flanges anywhere in my exhaust... all welded...

So how would I go about finding/making a length of 2.25" piping tapped for an O2 sensor?

I mean.. am I crazy to think that they should have assumed I wanted them to put the O2 sensor into the pre-tapped hole without me telling them specifically to do that? Is that rediculous of me to think they'd just automatically do that?

I personally think the guy who did it just wasn't happy that I showed up to have the work done at 4:15 when they close at 5... I think he just didn't give a crap and threw it on there... but if that were the case, one would think he would just go the easy route and screw the O2 into that hole not caring... I really don't mind that they wouldn't do it thinking it would mess with the sensor or my computer... it really bugs me that they didn't ASK before they permanently sealed the hole...

Ah Tony strikes again with his misinformed screw the customer attitude. Sorry Tim make sure you tell Marvin I sent you so you the the price hook up. Good luck man.




Semper Fi SAINT. May you rest in peace.

they ruined your part, make them replace it. a threaded bung is like 0.50 or so, they can drill a hole and weld one in. Because they sound like morons make sure the thread something into the bung when they weld it in, or the threads could get slag in them and screw up your sensor and when you take the sensor out and it just falls out they'll say, "some o2 sensors do that from the heat...."

fe%k that, maybe one in a million, but not right after you put it in with high temp grease, and I personally have never seen a stripped o2 bung on a J. correct me if I am wrong.


Fu%^ sakes I hate f#$king stupid exhaust shops... FU#$K


HP Tuners | Garrett T3/T04B | 2.5" Charge Pipes | 2.5" Downpipe | 650 Injectors | HO Manifold | Addco front/rear | Motor Mounts | HKS SSQV | Spec stage 3 | AEM UEGO Wideband | Team Green LSD | FMIC | 2.3 cams | 2.3 oil pump swap | 280WHP | Now ECOTECED

Its not a stupid exhaust shop its Tony's exhaust shop in Glen Burnie MD. He does stock just fine but ask him for custom and he gives you a deer caught in headlights look.




Semper Fi SAINT. May you rest in peace.

man how did they screw that up. Shop i went to in FL told the i wanted a 2.5" all with way with my new cat. I have to check my car again to see if the put in a bung or if the cat came with one.


2004 Grand Prix GTP (Competition Group)
SOLD-->1999 Z24 5M-#30 to register on JBO
"You can please some of the people some of the time but you can't please all the people'
all the time

sorry i lost track of this post


just have them use 2 1/4" pipe from the cat to where it is 2 1/4" for the cat back


then have them add the o2 bung for the o2 sensor , it just a matter of a 19-20mm hole and welding the bung to the pipe


but they will need to do the bung in the pipe , before they put it in the exhaust


if you have trouble getting a o2 bung email me , i can get them pretty cheap

The place where I got my exhaust done, just drilled a hole and welded a nut with the right threads after the cat.