After reading multiple posts about the OBX header, I'm really confused. My understanding of the MCS is that it has a pre-cat in the header followed by a main cat farther down the line. I've read multiple posts about people welding a cat to the OBX headers and don't understand why.

Lets assume I have a car that is used off-road only. If I remove my stock header and pre-cat assembly, can I simply bolt the OBX cat-less header in its place? Is it the same length and does it have the same connections as the stock assembly?

 

If your running off road - you do not from a legal stand point need a CAT. People are adding a CAT to the OBX header for street (legal) purposes. Pipe wise if you add a OBX header with out the CAT - you will be pipe short about 12" - basically the length of the CAT plus flange. But its simple straight pipe - no big deal add.

 

Am I right that there are two cats in the Mini? A precat and a main cat?

If so, removing the cat from the header would simply mean removing the pre-cat and the car would still pass an emissions test where I live. You would still have the main cat downstream. Right?

Does someone sell a straight pipe that fits or would I need to have something custom fabricated?

 

NO - The OBX header replaces - the stock exhaust manifold, precat and cat. If you want to pass emissiones test you have two options - graph stopck cat to obx header or purchase an aftermarket cat.

MIDAS/ any muffler shop can add the straight pipe - I don't think it qualifies as "custom" fabrication.

 

So the stock header has both a pre-cat and a main cat? If you weld the stock cat to the OBX header, do you end up with a main cat and no pre-cat? I guess I need to look at my car when I get home. I had an RX7 years ago that had a pre-cat in the header and a main cat farther down the line. It was quite common to replace the pre-cat with a straight downpipe. I was thinking the Mini had the same setup but I must be wrong. It would be nice if there was a bolt on cat that didn't require welding.

 

If you check other threads you'll see quite a few "bolt on cats" used with many aftermarket headers. I saw a guy with the OBX header and he cut the cat off the stock header and had someone weld a flange on to that end. He then bolted the header to the engine, the welded-on flare cat to the header and the cat flange to the exhaust pipe. Seemed to work just fine. I don't think you need the pre-cat to pass emissions (maybe not all states) but you sure need the cat, or some software that fools the engine into thinking it has one, and a sympathetic authority when they find out you don't have a cat on the road (!)

cheers,phil

 

It seems like for all the screwing around required for the OBX header including having to buy a cat and having to pay a muffler shop to do the install and welding the $950 or so cost of the Milltek header doesn't look so bad assuming you can bolt it on yourself.

 

The thing with that is, the OBX header is around $200 - $220 shipped, the Magnaflow cat or aftermarket cat is like $60 and to have a muffler shop install both and weld everything is like another $60, so that's what, $340 total?

That's why the OBX is a good deal, you save $600

 

I was guessing around $200 for the muffler shop labor assuming they charge at least two hours plus materials.

UPDATE: Just called the local Midas and explained the installation. They estimated $250-$300 knowing that the Milltek header could be installed in about 1.5 hours.

 

Sounds like the shop is charging a little much for that. MINI dealerships charge $100 an hour, so that would only be $150, so Midas should be able to do it for much less

 

I took all of the NAM information and pics posted and gave it to a qualified mechanic and had it installed (OBX header w/ stock CAT) for $400 BUCKS (parts and labor = all in). The job was turned around in about two hours.

 

I took off and installed my OBX header ($160 with shipping) myself in about 1 1/2hr's. Fit and finish was excellent. Install was simple.

I drove the car (sounded like a drag car) to my local "independent" muffler guy. He cut my old cat off the stock header took a couple measurements and welded on the supplied flange. He bolted it all together and we were done. He charged me $50.00 for his time.

My out of pocket cost: $210.00 .

Performance is great and the sound combination with my milltek still makes me smile.

 

All the screwing around (cutting and welding) cost me an additional .5 hours of labor at my shop, or $32.50.