Hello,


I purchased the OBX manifold online after reading many positive feedback online, instead I received a defective unit where the weld was too close to where the hole for the 10mm bolt is. All the other bolts are in except for one, I think it's leaking because I smell a tone of gas when I open the heater vents.


I need some ideas of how to tackle this, at this point removing it and sending it back is my last option because of shipping back to the US from Canada will be a night mare and the cost to remove it and install a new one..



I attached some images hope they will show up and give you enough detail.
Thank you for your help in advance.

 

I would simply use a Dremel and a small course grinding stone to remove just enough to clear bolt flange.
You should be able to find a small cylinder shaped grinding stone with just the right circumference to match the bolt flange. That way you're only removing what you have too.

 

Thank you for your answer, ...Sounds simple, but how thick is the steal? Would I be risking tearing a hole in the tube? or long term would it break or crack from heat? I just wanted to clarify that the bolt is hitting the tube the bolt fits into the hole without an issue it's the header tube that is too close and obstructing the bolt from going in straight.


thanks,

 

Thanks for clarifying this, I was thinking that it was just the weld that was in the way of the bolt flange so that it wouldn't start or seat properly.

In this case, short if sending it back, I'd see if I could find a local fab shop that could grind the weld back, dent the tube in, just far enough, and re-fill the gap created.
Probably wouldn't cost much or take much time.

 

Is it this company?

SETTING THE HIGHEST QUALITY STANDARD Founded in 1988, OBX Racing Sports is dedicated to manufacturing perfection at its best.


I would be all over them to make it right! Not on you to tinker or have exhaust fumes in your car.

 

I went with the OBX as well since my stock manifold cracked at the cat weld and I was in the same boat as you. Ended up removing some material on the nut so it would be possible to screw it on. I would've bought a RMW header, but budget wasn't allowing it and I wanted to get the car back on the road quickly.

I'm kinda disappointed by the quality, but I guess that's what happens to some companies once their reputation are made. I'll replace it with a RMW header once I swap the head/cam.

 

I'm glad we are sharing this about obx headers or obx manifolds. In the end going with the obx costed me more not less and now I'm driving around with one bolt off because the head was cross threaded.

It's super loud now on my jcw with borla race exhaust. Should I put the JCW exhaust back on? I'm tuning in next week after installing the sherick street CAM and 550 injectors. I wonder if the jcw exhaust can hold up with the new mods and 17% pulley. Any experince with different exhausts?

Thanks,

 

Thank you. I took your advice and emailed them. I bought it from eBay Member: motorsportauctions. He said he was not aware it was defective and offered a partial refund but i dont believe that. It was marked in red with an x on that tube. They are selling defective products. He said OBX drop shipped it to me. So someone is BSing.

 

It's not that the JCW manifold won't "handle" the mods, it's that it will change things. Won't be as open therefore won't make as much power, but more importantly it will effect the tune and you'd need a re-tune if you put a header on later. As far as the exhaust portion, the JCW is actually one of the best options, even with a header.

I actually ran a full '05 JCW manifold and exhaust with my first BVH, and it still worked, but as I stated above, it was of course less power and tuned specifically, and then re-tuned after I added a header.

It just depends on how many steps you want to take, if you'll be happy with no header, or if it's worth it to you to pony up for a second tune.

 

Thanks for the feedback. Actually my ideal setup would be the performance headers with a JCW exhaust but i was worried that i would sufocate the car? Sounds like you had good experince with headers and jcw cat back. I can swap it before the tune. Its sitting in my locker at home. Takes about 30 min. I feel the sound on the boral without the cat is a bit too much. It might even fail sound check at the track. My gf today was pointing out how the mini was way louder that the 18wheeler beside us :/ haha.

 

No, it won't suffocate the car at all, it actually works out to have "just the right amount" of back pressure.
I'm running the Mynes V-2 header with my JCW exhaust, to me it's not too loud under normal conditions, but has a louder and excellent sound under heavy throttle.

 

That is pretty strange stuff. From the the photos it looks like the port is not equal distance between the mounting bolts. Are you sure the ports match up to the exhaust ports? The welds don't look bad, it's not built up differently near the bolt holes. The port just looks offset. Maybe it is just the way the photo was taken. Before making any modification by grinding away I would ensure that exhaust flange is correct.

 

oh god not the whole 'back pressure' thing again!

You do not need back pressure.

You NEVER need 'restrictive' back pressure.

What you need is scavenging, and that comes down to collector and post collector design.

Basically you want the exhaust gasses from cylinder 2 firing to cause a negative pressure wave as they pass by cylinder 1 exhaust runner in the collector that travels up the cyl 1 runner and helps pull fumes out of the cylinder to promote better fill on the cyl 1 intake stroke (and so on and so forth for the other cylinders)

now let's stop beating a dead and disproved wives tale of a dead horse please!

- every engineer ever


scavenging conversation starts around 5:20

 

kaneguy is on the right track. OP, did you compare the port alignment by simply using the exhaust manifold gasket as a template? This will tell you if the header ports are aligned properly with the exhaust ports on the head. If not, you will not get a good seal with the gasket.

 

Thank you I will be doing that tonight. I was also concerned about this but did not know how to test it.

 

I will have a look today, I removed the Borla race (I like it but just too loud at full throttle) and slapped the JCW back on but was missing a band clamp the one I had did not hold the pipes together maybe they stretch or something so I ordered a new one. so while I work on that tonight I will also check the manifold and head ports alignments.

 

 

Ouch, nice product but I'm sure that was a big difference in price lol. Looks good though!

 

Looks fantastic. How do you like the sound. I'm thinking about getting the same. Currently, I have the factory JCW exhaust still on the car and am thinking the Milltek with it's 4 longer tubes will let the exhaust flow better and maybe a little power gain. Your thoughts, experience since the switch? Thanks

 

Hi Bernard, it looks fantastic however, I measured my JCW head ports compared to the ones on the Milltek header and the header ports are smaller than my actual head. so not a good start. The Milltek is using the same port size of the cooper S so if you plan to put this on a cooper S and not planning to upgrade the head than sure will do the trick but if you have a JCW head or any aftermarket ported head you will regret buying this header. The primary tubes are smaller also meaning that porting the header is not really a good option and I don't think the Cat would perform that well with a BVH. so just some things to think about.

 

bilal074, thank you so much. I have the JCW head and your explanation clarifies what I've been trying to find out for sometime. Much appreciated.

 

Milltek (gasket perfectly lined up)
Stock r53 header same size even slightly larger than the milltek

 

I had similar issues with the OBX as OP. Ended up dremeling the weld out of the way a bit and also took out some of the bolt head flange. Even after that it was a tight fit for that one bolt. Seems that the bolt hole is slightly out of place on the header.

The header ports are in the correct place, and they are larger than the ports on the head (even with a BVH). But the tubing is even larger, and not exactly centered on the ports, which I think creates this issue.

I think the next time the header comes out I will try to enlarge that bolt hole on the header and dent the tube a bit...

 

Thanks for posting these side by side details of the Milltek vs Stock header at the flange. I have noticed that the 4 feeder tubes on the Milltek seem to be of larger diameter than on the stock, and that is the reason I lean towards the Milltek being my top choice should my stock header die because of the cat committing suicide. Based on the photos, seem it is possible to clean out (with an pneumatic grinder etc) the obstructions around the 4 openings on the flange off the Milltek to match up with the enlarged exhaust ports on JCW head.

It would be nice to see the same details on the much touted RMW Shorty header.

One point that can easily be overlook, is leaving enough mating surface between the port opening to ensure a secured seal. There is not a whole lot of meat there between the port opening and the bolt holes.