[atmosphericM]

Hey guys,

I am eyeing the aFe front-pipes for a little extra power and sound but noticed in the installation instructions that they require unbolting and not using the OE brace that "connects" the front-pipes to the chassis (transmission, technically, IIRC). I'm also guessing that they would not re-use the clamps that hold the two OE front-pipes together just after the secondary cats.

I'm guessing that the reason for this is because the aFe front-pipes appear to be larger in diameter than the OE pipes, except for right where they connect to the mid-pipe.

What is your opinion regarding the importance of these two braces? And, do you think that OE braces could be modified (bent?) in order to accommodate the larger aFe pipes?

Personally, I'd really like to retain the braces as, IMO, there will be a good deal of extra stress placed on the exhaust manifolds and/or mid-pipe without them. I imagine the BMW engineers put them there for a reason, after all. Or maybe it's the other way around, seeing as how the pipes would be more free to "torque" as the engine moves around?

Thanks for your input!

-aM

[hassmaschine]

I think BMW put them there for a reason.

[BudVlad]

I think the braces are there to support the heavy cats. No aftermarket headers are using them. I have aFe headers since January 2014, no braces and no issues.

[hassmaschine]

oh, hah, I thought he was talking about an intake - by 'front pipes' he means headers?

[The Nightman]

Do you mean #12 and 13 in this diagram?

http://www.realoem.com/bmw/enUS/show...diagId=18_0588

I wasn't able to reuse it with my AFE midpipes due to their larger diameter. No issues since I installed them 10k km ago.

[atmosphericM]

^^ I am talking about #12/13 as well as #6/7 from the photo above. Thank you freedomfries, perhaps I should have been less lazy and posted a pic myself.

I refer to the pipes with the secondary cats as "front-pipes" because these cars are confusing and have two mid-pipes I guess, or whatever. Headers (manifolds) -> front-pipes -> mid-pipe (y-pipe) -> rear section (incl. muffler).

BudVlad, even though I assume you are talking about the headers themselves, you make a good point about the fact that perhaps the braces are only on the OE parts because they have heavy cats.

I just don't want to cause any stress cracks on the manifolds where they are welded to the flanges near the engine (resulting from weight?) and I also don't want to cause any stress cracks on my new shiny PE y-pipe (resulting from the front-pipes separating?).

Hmmm, no braces = weight savings, rite?? lol

Thanks for chiming in, guys. All opinions appreciated!

[The Nightman]

I was able to reuse #6/7 at the end of the AFE midpipes, where the diameter decreases.

[atmosphericM]

Oh, cool! From the photos it didn't look like there would be space to fit the brace + the sleeves (exhaust clamps). That's good news. Thanks

[Eagle1oh7]

I didn't try using the brace when I installed my Einsemann, partly because I couldn't undo the center bolt that holds the bottom and top together. Exhaust is still good lol

[fravel]

I deleted the braces #12/13, but I was able to reuse #6/7 in the factory position by getting some longer bolts, the factory bolts were too short.