Hey guys, so I just received my Ireland Engineering cat back and X Force 4-2-1 headers. I know they're on the cheaper end, but my R53 is my daily (spirited) driver and inflation is at a 40 year high.

Well, I see that IE cat back has clamps and seems straight forward to install. But the X Force headers didn't come with a cat or test pipe. So at this point I'm wondering if I should get my old cat with 125k miles on it, as far as I know. Or a universal catalytic converter? OR since I live in SC I could just get a test pipe and basically straight pipe it?

I understand a straight pipe set-up will be noisier, maybe a smell, not really a concern. Does anyone have any experience with universal cats? I prefer to flanges welded on to be able to remove cat section. Any thoughts, advice, and ideas is greatly appreciated.

Thanks NAM'ers.

Edit: What are those parts for that came with the header?

 

If at all possible, spend what it takes to use your old CAT, or another OEM CAT.
This will head off possible problems and Fault Codes, and as you've mentioned, keep the sound volume down to a reasonable level.

 

The X-force is the latest copy of the SuperSprint 4-2-1 header. To find more info on NAM search for OBX header as it was the original knockoff. They’re a bargain compared to the SuperSprint, but sometimes have fitment issues regarding clearance with one or two of the mounting bolts on the head.

The extra parts are to mount the cat to the header with a flexible donut gasket. The gasket and flange offer a little movement/rotation instead of using a traditional flex pipe. Most of the SuperSprint/OBX installs I’ve seen use the stock MINI cat. The last two pics from this old SuperSprint for sale ad show how a stock cat looks with the flange welded on.

https://www.northamericanmotoring.co...nt-header.html

 

I don't know, but I'm hoping you'll post your opinion about your exhaust once you get it installed. I'm really tempted by the IE catback exaust. I'm pretty hesitant to install a header because I only have jack stands, and I'm pretty nervous about breaking off exhaust bolts in the head.

 

Yea, I'm 33 year's old, I definitely do not want people thinking I'm trying to build my MINI into an environmentally harsh ricer. I was looking through some OBD codes and it appears my CAT has actually thrown some out there, the latest was 0171 - Mixture too lean. It hasn't thrown a light, I just found it looking for DSC codes (had a Trifecta problem).


I was actually going to get the OBX as they were cheap, good design, and almost everywhere 3 years ago, but I see they've doubled in price. XForce is an Aussie company so I don't mind supporting them. Ah, any recommendations on a good flex donut?
As for the for sale thread, that brings justice to "a picture is worth a thousand words". Those pics alone explain a helluva lot of what I need to do.
Thanks guys. You have no idea how much that puts everything into perspective. (This being my 1st time modding a complete exhaust, I'm not so knowledgeable.) Very much appreciated, would send a 6-pack your ways if I could.

 

From your header pic it looks like you already have your donut, but it’s not a bad idea to have a spare, or two. I’ve read over tightening the joint and fully compressing the springs will wear the donut out fast.

 

I will be keeping this updated (to make a donation to the MINI community for info on both the XForce header and the Ireland Engineering Cat Back). I know I can't be the only one who didn't want to spend over $2000 on an exhaust.

As far as breaking off the header's bolts, I'm not too worried about it. I've had to remove the header's on both my R50 and R53. They both cracked and needed to be patched. Wasn't too hard, just used penetrating oil and took it slow.

You're 100% correct. That goes to show my ignorance of exhaust system components. I was thinking of a flex joint! Which this set-up doesn't have. Stiff.

 

Well, got the old exhaust pulled out, just kept it in 1 piece instead of butchering. I'm pretty surprised at the condition of the orange rubber hangers, they're not broken and still pretty stiff, I should have this installed by the afternoon (cat back only, so far), but I can't get to the bolts to remove said orange hangers...
Edit:


I've seen some DIYs with people replacing the exhaust hanger hardware by removing caps over bolts. Guess that's just an R50 thing or 2004 change up? Any who I figure instead of buying that bracket the studs are attached to I could just drop some bolts in.

So, yea I've given up for the time being as I apparently had no right rear exhaust hook. That's a bummer, figured I could just use the left side (since my cat back only has one muffler), but it's not a match. So waiting on mid exhaust hangers and the hook. In the meantime, I'll be drilling out 2 bolts that just popped in half. It's been a challenge get that heavy pile of rust out from under the car. Well, next weekend it'll be done, with new hardware and hangers all around.

 

I hate threads where the OP says they'll keep it updated. 😒 Like I said I'll keep it updated and honest.

Welp... Obviously I've have the catback on for a good month or so now. I'm actually quite surprised at the quality of IE's work. So far so good 👍, it sounded slightly raspier with the OE header and cat. Very lightweight and free-flowing. I'm pleased with it.

The XForce header is on... and well, its straight piped, for the time being. I didn't have work today and decided to FINALLY get the header welded up. It's funny as I was told by quite a few exhaust shops that they would not reuse the old catalytic converter. Some shops wouldn't even touch the MINI! BUT a few shops would straight pipe it... Oddly. 🤨 So $320 for a header weld up, AND they tried to keep my old header and catalytic converter.

Well, I can say the setup is:
1.) Very free-flowing, maybe too much. The low end power doesn't seem the same, but higher speeds are nice, bit of a boost over 60+, could just be all in my head.
2.) IT IS LOUD. Now yes, of course it's straight piped, so that is to be expected. But as it sits at the moment I won't be driving it too much until I get that under control.
3.) The IE exhaust rumbles so much now that the mid pipes hangars rattle right up under the exhaust pipe corridor, that I can easily manage to fix.
So, I smell like oil and gas. My MINI sounds like a fart can. Little to no pops, rasp, or burble with the header installed. Also, I've noticed that underhood temps are slightly lower. Before the cat was removed it sounded nice.

Now I'm in search of a catalytic converter that can add some backpressure. Throw a Vibrant resonator or 2 in there.

Suggestions? Thoughts?




[rant]...Catalytic converters are great and manufacturers integrate them for a very good reason. Straight piped vehicles are filthy, stinky, and sound horrendous. [/rant]

 

I understand why you would want to add the cat back in, but why would you specifically want to add back pressure?

 

The car's power has dropped tremendously when in 1st, 2nd and half way through 3rd gear. My shift point to take off from a standing start is averaging 4k RPM. That's to get a quick yet comfortable start - think stoplights, 5 o'clock traffic in the city, turning onto a busy street.The exhaust just roars but the car's power isn't what it used to be. At higher speeds the car feels more spirited, a noticeable increase in power going into 4th gear. The exhaust's noise level actually decreases here, yet the car pulls very strong all the way to the top of the power band.

I can only attribute this change to the lack of back pressure effecting the exhaust gas scavenging pulses in a 4-cyl supercharged motor.

If this doesn't sound right, I would GREATLY appreciate some advice.

Last night I must've spent 5 hours researching how exhaust systems, unwanted turbulences, flow, restrictions, back-pressure, gas scavenging, and how they effect FI and NA engines. They're more complex than I ever would have expected.

 

So I take it you're actually concerned about pressure wave reflections off the cat rather than back pressure, right?

I don't fully understand why you would have poor performance in different gears. Scavenging is engine speed dependent.

I'm mostly just curious. There are a few people who have run the R50 with catless headers without significant issue, though supposedly a full exhaust, intake, and cam maxes out the dinky injectors.

 

Well, you know I was completely wrong and had TOO much faith in the muffler shop doing quality work...

The shop didn't even attach the exhaust together!

Their work was absolutely horrendous, yes. That is the o2 sensor pushing into the heat shield.

The midpipes prongs that attach in the gasket have worn a hole through the heat shield!

I didn't know this until last night as I've been driving my Infiniti all week (have been driving long distances for work, and putting in 60+ hours)

Anywhoo, the shop welded the straight pipe at an angle, so nothing lines up. This morning I took the MINI to a more professional auto shop, they do all of our fleet vehicles, and everyone in the shop they wouldn't be able to do anything with exhaust now. Not weld in a new cat, the OE car, or even center up the straight...

·• The mechanics all said it's a Federal offense for a commercial shop to straight pipe or do anything that effects the catalytic converter's filtering ability!?

·• Another opinion was that the headers NEED the flex joint, without it the headers absorb the engines torque and flex... Making them liable to break when hot even though I have Power Flex bushings all around?

Well, any thoughts to share? Is there any possible legal action? I paid the shop $320 just to weld in a piece of pipe, no other shops agreed to do the work.

Anyone heard of the OBX, XForce, Becker Performance, or Super Sprint headers breaking?

Tomorrow I'm taking the MINI back to the muffler shop that performed the hack job and see what the manager has to say...

 

Yes. It's against federal law to remove emissions devices, but a lot of people do because nobody checks in a lot of places.

Yes, you need some sort of allowance for movement. I thought your header came with a ball joint for that though?

Why aren't there any bolts holding your cat-back to the test pipe? Is it just loose there?

 

The XForce header came with a flexible donut gasket, they offer a little movement/rotation instead of using a traditional flex pipe.

Nope, my exhaust wasn't connected when I left the exhaust shop. That gap was present when the mechanic pulled it around. After a few hours I didn't even think to have a look under the car, the shop supposedly has good reputation, and I was eager to "hear the new exhaust", eh. Undrivable.

Monday or Tuesday will hopefully be able to get this sorted. For the time being I can't even drive the car, even though I managed to seal the gap. This is what a completely botched up job looks like.

 

good lord. I’m sorry that happened to you. Somehow the lack of any fasteners makes it seem so much worse to me than the crooked test pipe, though I suppose that really shouldn’t be the case. The O2 sensor banging the heat shield is probably the worst part. Or maybe not. It’s all pretty shoddy work…

I guess I’ve never really thought too hard about the difference in flex between a flex joint and something like what your header has.

 

Beyond shoddy if you ask me, just unacceptable. I did take it back to them this past week and they managed to "straighten" out the test pipe, but they wouldn't add flanges or the cat con.

I've got another mechanic willing to work with me, but his biggest concern is the lack of a flex joint/pipe.

Anyone with OBX, Super Sprint, or XForce headers on the best place to add a flex joint or what's the best way to add some flex in the system? I'm combing through the forums and can't find much on this header design breaking... Doesn't seem impossible.

 

I too have been following this tale of woe. It's likely very difficult to write-off all those wasted $$ with your original stated intent being budget oriented. As a do-over, thinking a better overall choice would have been the much more spendy Milltek header which is complete with flex pipe, cat and flanges ready to install. The topic below illustrates that well plus with links and comment by Way Cooper that the Milltek header is now made with additional flanges allowing use of cat or test pipe. I mentioned in there that my header brand is unknown but appears very similar to the Milltek if not the same circa 2006 when installed. Also noting my prior thinking that the header cat flange position being too high causing resonator interference with the heat shield adjacent to the shifter box has since been determined not that root cause but instead, the B&M SSK extended dust cover enclosure that hangs much lower (1"-1.5") than the OEM shifter box.

JCW vs Milltek Cat

 

this is what me and my buddy did , we both luckily had “straight cats”

With one 02 bung

With two for afr readings
hope this helps
bolts directly onto my xforce