I got my OBX header back from being coated Friday and got it installed. Northwest Industrial Coatings did the ceramic coat $130.00 inside and out no shipping cause they were local. As you can see I also used a magnaflow 2.5" in/out Cat. I didn't want to cut up my stock cat in case I want to go back stock, plus I wanted the cat pipe size to match the header size. Looks real good.

It was quite a chore to get it fitted up but finally got it in.
The only potential problem I see is the 02 sensor position on the mag cat compared to the stock cat. It winds up being tucked up into the corner of the heat shield area (see diagram). There's about a quarter inch of clearance between the end of the sensor and the shield and I'm a little concerned about it rubbing. I'll have to keep a close eye for a while.
Next step is the 15% pulley and plugs.

 

That looks great! Nice idea bolting the two systems together like that. I also have the OBX header and am gathering up the pieces to install it this spring. Just out of curiosity, did the magnaflow cat come with the O2 sensor already installed? Or is that something you had to have done? Do you happen to have the part number for the cat? I looked on Summit Racings site and they have several listed with 2.5" in/out but none seemed to show the O2 sensor and it's not clear what length the body is on the cat. Any help would be great.
Thanks,
Bob

 

I think it's www.performancepeddler.com, anyway, in looking through old reciepts, they did mine (94166) for $58 and some change... It was a two bung set up, and yes, the bungs come pre-mounted). Just checked the site, it list for $80+

Also, I rotated my cat so that it didn't push the 02 sensor up, but it doesn't look as symmetric.

Go to the magnaflow site to select what you want, then search on the PP site for the price, then call them with a low ball offer, they'll respond with a very competitive price.

Good luck!

Matt

 

94136 2.5" in/out with single 02 boss, $76.93 on the site now....

Matt

 

The cat doesn't come with 02 sensor It's threaded so just use the stock sensor.
It's the magnaflow 94100 series single 02 boss.
I got it from http://magnaflow.performance-curve.c...PROD&ProdID=90
Cost me $65.00 plus ship.

Measurements are as follows
Detailed Description MagnaFlow Catalytic Converter
High Flow
Stainless Steel with Aluminized Heat Shield
Universal Replacement Converter
Dimensions:
Body Length- 9"
Overall Length - 13"
Body Width - 6.5"
Body Height - 4"

I had to cut about a half inch off each end of the cat. Since I was going into the 2.25" stock exhaust I had a flange made by a muffler shop cost $11.00. I made it a slip joint with clamp instead of welding it so I would have some adjustment room.
As others have found out, double nut the spring bolts.

 

I had problems with a few of the header bolts as the tubes are angled differently and it was a real pain getting them started and getting a socket on them.

I't a good idea to start these bolts first and have an assortment of flexible socket extensions.

 

Thanks guys! just placed my order with magnaflow for the metalic catalytic converter with a single O2 sensor bung. it was $65 and change with free shipping.

 

looks great.

Now that you got it in what's your driving impressiones?

 

Be careful with the end of the O2 sensor wire close to heat shield. I don't have OBX or magnacore Cat but Miltek gave me 02 extension for my Miltek header/Cat which was throwing codes. It put sensor about 1/2" closer to heat shield. During first autocross i shorted out & destroyed sensor from hitting heat shielding.

 

Well I took it out for a few hours lots of mountain driving down here in S. Oregon.
I didn't really feel that I gained any H.P. but the power was there especially going uphill, keep in mind I have an MCSa.
Sport mode was a lot beefier.
I love the sound deeper gurgle on throttle down and powerful growl when taking off or WOT. Normal sound at cruise speed. I like
I'm glad I kept the stock exhaust it may have been to loud otherwise.
Next comes the 15% pulley and plugs. I haven't decided to go with Randy's or Mini-madness. I'm going to PDX next week to take it in for it's first service at Rasmussen BMW so Mini-Madness may be my choice since he's in Portland and he pretty reputable.
In the meantime I'm installing my Blinder Xtreme 20 Laser jammer to complement my Bel radar detector. Laser camera cops in Oregon are rampant and out of control. Laser jammers are still legal here.

 

Don't forget Alta is Portland also. The PDXMINI club is holding a tech/mod day this next weekend and Alta is coming to help with installs. Check out www.pdxmini.org for details.

Keep us posted with your long term review of the header also.

 

A dyno showed only 1-2 hp gain but 6-8lbs of torque gain! So the car should like those hills even more.

Consider matching up your header w/ the 1-ball exhaust - this is a great package - price, performance & sound (makes just a tad louder).

 

Bahamabart:
Not to hijack this thread but I see you've also installed the OBX exhaust system. How is it between 2500 and 3500 rpm? I'm wondering about my commute and if it's going to drive me up a wall... loud at WOT wouldn't be too much of a surprise but at a steady cruise might be a problem.

 

How did you get the header and the cat to match up well for install? Did you have to take the stock header off to do this? The reason I ask is, I would like to have thea header and cat made up before I have to take the stock one off for installation. Is this possible?

Garrett

 

As shown in the first pic I matched it up off the car by clamping them next to each other.
If you use the cat I used you can pretty much get away with cutting a half inch from each end of the cat.
As noted I used a 2.5" to 2.25" slip connector with a 2.25" flange welded to the connector on the output side of the cat. I had to cut the slip connector to length to get it right, that's why I used the side by side to get me in the ball park.
The flange was part #323 but that may just be the welding shop reference.
I took the stock head to a custom muffler shop and we matched the flange with head. Seemed to be a universal flange.
I did not weld the slip connector to the cat. Instead I bolted it to the stock exhaust (with new gasket) then slipped it into the cat which I already had bolted to the installed OBX header. I left the spring bolts on the header loose enough to move the cat down enough to slip the connector in. You will have to leave the center pipe plate (don't know what else to call it) off till last also in order to get it together. Once it slips in tighten the spring bolts then the clamp around the slip connector.
One thing, after starting the car get underneath and tighten the spring bolts until there is no exhaust leaks then finish tightening the clamp on the slip until no leaks. Check it all again for leaks after driving.
The only reason I used the clamp instead of welding the flange to the cat is because I may later decide to use a 2.5" cat back exhaustand I want to be able to remove the 2.25" slip.

 

First you can do a search "obx exhaust" for I really tried to describe the system and the install. Now that i have some miles on it the tone has changed a bit and I will share.

1) its loudest point is 4,000 rpm in first gear.
2) If you are on the throttle this is a loud system but then isn't that when it should be loud?
3) highway cruising 55 - 70 mph it's quite. For me the system is a non-issue when highway commuting.
4) Bear in mind that the system does not come with a resonator. If you look at SS - its an option. There are resonators on ebay like for 30 bucks so if its too much, you can add a resonator.
5) I'm running the header as well so the tone is deep and w/ gurggle.

My conclusion is for the budget/performance minded enthusiats you get alot for 650 (header plus exhaust). If loudeness is an issue then I think the best bang for the buck/performance is obx header plus 1-ball which I had and liked very much.

 

For those thinking of installing the OBX header. OutBackBob did something that I did not do but recommend and that is how he aligned his new system to the old one to ensure the same total length. If you are going to re-use the stock cat, I suggest you measure total length so that when you put on the new system, you don't push the exhaust system out or pull it in. I did not do this and it ended up pulling my 1-ball in about 1/2 inch which I corrected when I did the obx exhaust.

ALSO most improtantly, you MUST either double nut the spring clamps or use copper nuts otherwise it will come lose. This seems to be one of th ebiggest problems people have had with this type on connector. I did get this right the first time using cooper nuts and have had no problems whatsoever.

 

Recommend a final step for install: Double-nut or safety wire the spring bolts. Some of us have lost the nuts off the springs.

 

Yes I second that emotion double nut the spring bolts!
I didn't do the copper nuts, my experirence is yes they don't come loose but also they are hard as hell to get off if you have to change the donut which I believe down the road we will have to do.
Either way is fine though. OBX should note it or add the nuts to the kit.

 

Getting mine installed tomorrow, along with a rear sway. Cant wait.

 

I'm a little confused after reading this thread. Can I simply remove my stock header and replace it with the OBX header leaving the original cat in place? Why does the first post talk about not wanting to cut up the original cat?

 

In very broad terms the OBX HEADER replaces the stock header which has the stock cat attached to it. So NO, you cannot install the OBX header leaving the original CAT in place. Assuming you want to run a CAT - you have two options -

1) grapht on the stock CAT to the OBX header.
2) purchase an aftermarket CAT (can or cannot be more free flow).

 

To use OBX headers you must cut the stock cat from the stock header and weld a bell shaped flange adapter to it so it will fit up with the OBX.
I didn't want to do that to my stock header in case I ever want or need to bring it back stock. I only had about 2500 miles on the car and didn't want to chance screwing with the warranty. Besides I wanted a high flow cat and it works great!