R56 exhaust questions/ideas
 

I have been considering fabricating my own exhaust. I am thinking of all stainless from the downpipe back, removing the second catalytic converter. I am wonder if it is a straight shot from the v-band clamp to the rear? I am thinking stainless flex pipe to straight pipe to muffler to tips. Is this possible? I'm capable of welding, but don't have a mandrel bender. Judging by the pics of ost stock R56 exahusts, it seems they have bends, but they don't look necessary.

Forgot to ask, is the v-band clamp a standard size?

You can make straight. There are some slight bends and you will see that when you lift the car up.

Nice, thanks! Gotta figure out what size exhaust makes sense for my target mods. I don't wanna go bigger than necessary, thinking either 2.5'' or 3''. Probably gonna use a Spintech muffler and do a Porsche Cayman exhaust tip.

I'm pretty sure if you made a straight shot from the downpipe back that you'd run into the cross brace that sits mid frame and also the exit of the exhaust would be around 8" too low from where it should be in relation to the rear bumper.

That's the kind of info I was looking for and I am hoping that issue can be addressed with the flex pipe in the stock location. I figure over that long run, if I take advantage of the positionability with that flex pipe, it may put me where I need to be or at least close to it. Might have to get an exhaust shop to make some very small bends at the most I think.

Not to be a nagging Nelly, but if you can weld, why do you need a bender? There are plenty of places that sell SS bends. Cut and weld, and soon you will be in what the hell is that droning world, without a resonator.

Oh, and you can weld SS? You have a TIG welder? (I do...lol)

I may grab some of those bends and mess with it a little in aluminized. Honestly after looking at how much of a PITA it's gonna be, I am going to get a pre-built exhaust. I don't think there is anything to be had by building my own except saving a couple hundred dollars. I'm thinking if I wanna experiment, I can use aluminized tubing so it's cheaper and then if I come up with something nice, make it in stainless. I am such a DIY guy that it's hard to pass up making it myself, but the polished Invidia and Riss exhausts are just too nice.

I don't have a TIG, I have a MIG with gas.

I have an exhaust guy here locally that has done the exhaust on my Volvo S60 T5, my WRX and now he will attempt my MCS. My question today is do I go with 2.5" or 3.0"?

With all the research I have done I see a lot of companies use 2.5" but there are a few 3.0" out there. What to choose?

My Volvo was a 3.0" and the WRX was 80mm, granted these cars have bigger displacements and MUCH bigger turbos. I am torn between 2.5" and 3.0"

BTW, this exhaust is just temporary as I plan to go full turbo back/tune when I can scrape up some more cash.

3" is a little big unless you have the power to support it. 2.5" does really well especially if it is catless.

Hey Porthos,

I just peeped under my ride and noticed a small (what looks like a cat) just prior to the resonator, can that be entirely removed without problems during the emissions process?

And when you say 'catless' do you mean all of them or just that secondary cat I mentioned about above?

The small cat is not monitored for emissions and can be removed. The JCW does not have the small cat as standard equip.

"Catless" generally means all of them, and will generate a check engine light, which will not go away without a tune.

2.5" will be plenty big even if you keep the downpipe cat. Good luck.

Thank you so much for your input, much appreciated. I was reading the instructions for the install on the Borla cat back system and they suggest cutting the exhaust system off 4" before the second cat. Done and done.

So their isn't any issues with running straight pipe? With or without the cats? How about the back pressure? I'm thinking of doing something similar but I want to make sure I'm not going hurt the engine or loose power with out back pressure.

Without any cats = check engine light if you don't have a tune to eliminate the code being thrown, so that is one small issue.
Backpressure is not a factor on turbocharged engines. You could eliminate the exhaust pipe completly, but you may end up warping your hood scoop. have fun & good luck.

Yep that be the truth. If you are running a pretty strong tune with some turbo work and some other engine work 2.75" or 3" would work but it is not needed.

Okay, everyone. Thank you for lots of input and thoughts.

I will be having my exhaust put on today. 2.5" from the flex pipe back. Here is the question, do I use a resonator or not? I know that the turbo will eliminate some raspy-ness but will it be too loud without a resonator?

I would try it without first. You can always add one later to quiet it down a little.

I decided to rock a resonator. 2.5" from the flex pipe back. Magnaflow muffler with two 4" double walled tips. Lifetime warranty. Sounds friggin' epic and looks the part. All for a fraction of the price. My exhaust guy is the man. Spools up considerably faster, tons more low-mid range torque and top-end feels stronger too. Throttle response in Eco mode is damn near the same as in Sport mode.

Hats off to you all for your advice, input and suggestions. You all rock :thumbsup:

Care to put up a youtube video of the sound?

Good morning,

I would love to post a video actually. Please be patient with me as I have a couple busy weekends ahead of me. I will get you something early next week after the long weekend :thumbsup:

Just so you are aware I have since removed the resonator from my exhaust. I wanted more sound. It sounds just as smooth (thanks to the muffler) but has a little more volume to it. The resonator was 'turned' backwards for better flow but still necked the system down a little. I removed it and wow.

I would like to do a 3" now. So this one could be for sale if you like it :wink:

I know this is an old thread but did you ever post a video?

Hello,

I am sorry that I was unable to post a video or sound clip. I sold the MINI back in July of 2014.

I have discontinued the use of this forum but wanted to respond to your post as this was one that I was still subscribed to.

Thanks,

Matt