I've decided to go with Borla's cat back for my 2010 R57. It looks like everyone says to go 2.5 instead of 3 inch. The Borla says their system is 2.25. Do you think that quarter inch matters?..

 

Actually I talked to someone at Borla about this and it's all about exhaust velocity. A bigger pipe lowers velocity in exchange for volume, think of a garden hose ones a half an inch thick, the other is 1 inch thick, which one do you think is going to have more pressure or should I say velocity? Then you must think of port velocity on the intake and exhaust runners and exhaust manifold, it's all tied together.

Now if you're upgrading your turbo and getting a manic stage 3 tune, 2.5 inch sounds about right. If your going for a huge turbo you need to start thinking about everything past the turbo, intake and exhaust porting, exhaust manifold porting and exhaust pipe diameter.


You're going to love the Borla S-Type Exhaust especially if you're running a downpipe, it gets pretty aggressive at that point.

 

I just installed an S-Type catback on my 2012 R56. My understanding from the info from Borla is that it is 2.25. My Borla went on so easily. It lined up super and everything was packaged really well. I absolutely love the sound. Deep, throaty and really rips when you get on it, but not "annoy the neighbors" loud by any stretch.

It sounds very "tuned" not just louder.

Seat of the pants is tough to tell really, I don't believe you gain much with just a catback. I do have an AFE high flow drop in filter too.

I am sure you will be really happy with a Borla.

 

Thanks guys, I'm looking forward to it.
Do you think it’s worth it to have it installed by a shop so it can be welded instead of clamped?

 

I don't believe with the Borla you will need to. The two clamps are very high quality and seem to be doing a great job. I installed and torqued the bolts correctly. Ran it through a 60 minute run and heat cycle. Then the following morning checked the bolts again with a torque wrench and everything was tight. I'll be checking it again this weekend, but no leaks evident, no leaking noises from below. I believe if you use a torque wrench and ensure everything is lined up it will be great.

Also, I used a chain cutter exhaust tool that was in new condition. Smooth, easy, tidy cut!

I placed my MINI on four jack stands on my garage concrete floor. *** Never jack stand a car on asphalt ***

 

The instructions say to cut the stock piping 4" inches (on my R56) after the second catt, then all you do is slide the Borla piping on and clamp it tight. The Borla piping is flanged just enough to slide over the stock piping.

I'm not 100% percent sure if you cut 4" inches on your R57, so please rely on your instructions! You can download them from Borla's website.

 

And velocity essentially equals torque.

I used to run 2.5" system on a naturally aspirated fox mustang. Upped the exhaust to 3" and lost some low end grunt noticeable by the buttometer.

Larger diameter allows for higher horsepower but you can lose torque unless other changes are made.

I think you'd be fine with what they recommend.

 

Let me know when your ready for the borla exhaust!

 

Update:
My Borla S-Type installed using just the two clamps that came with the kit is still rock solid, no vibrations, no loose clamps, no signs of exhaust leaks and it sounds awesome!

I have put almost 2000 miles on her since the installation.

 

That's great to hear, thanks for the update. I've just about got the funds together. Now the hard thing is deciding, do I go with the exhaust or an intercooler. each are about the same price, I'm going to do both just can't decide which one first..

 

I think that the Borla exhaust tips look better than any other exhaust tips on the market!

 

It really changes tone and attitude with the sport button on!

 

Go with the intercooler as you will actually notice a power gain with that. The exhaust is just a noise maker. Since your looking at the Borla that is just a rear muffler anyway so you won't gain any power your only going to get sound.