[dlbrooks18]

What size diameter x-pipe fits stock E90 exhaust?

http://www.summitracing.com/parts/mpe-10791

[07tundra]

2.5 that's what I run

[dlbrooks18]

Originally Posted by 07tundra

2.5 that's what I run

Thanks

[CustomColours]

Why is that one any better than the one that is already on the standard exhaust.

[BigHoncho]

2.36" (60mm) to be exact

[osukf09]

Originally Posted by BigHoncho

2.36" (60mm) to be exact

I thought it was 2.36 ID but 2.5 outer diameter which is what it's normally measured by

[dlbrooks18]

Originally Posted by CustomColours

Why is that one any better than the one that is already on the standard exhaust.

From my understanding the E90 exhaust is a bit more tame due to the fact that it doesnt have an xpipe like the E92 oem exhaust. For those that have done this mod, did you notice any real difference- more gurgle and pop?

[shadow191]

E90 doesn't have an X-pipe I believe, it has a resonator. So putting this one in should make it louder. It may also free up some restriction.

X-pipe should sound better than just straight pipes since it's merging and crossing the exhaust flow.

Originally Posted by CustomColours

Why is that one any better than the one that is already on the standard exhaust.

[CustomColours]

Aaaah. I see. I assumed both had the same exhaust. Gurgles and pops are never a bad thing.

[superbang]

The xpipe didn't make it to much louder on my e90. Even with the full magnaflow exhaust.

http://www.e90post.com/forums/showthread.php?t=780900

[BigHoncho]

Originally Posted by apjr09

I thought it was 2.36 ID but 2.5 outer diameter which is what it's normally measured by

2.36" = outside, inside = 2.24"

[dlbrooks18]

Originally Posted by superbang

The xpipe didn't make it to much louder on my e90. Even with the full magnaflow exhaust.

http://www.e90post.com/forums/showthread.php?t=780900

Interesting, so maybe not worth it would you say? Thanks.

[osukf09]

Originally Posted by BigHoncho

2.36" = outside, inside = 2.24"

Ah okay, thanks for the clarification. So it'll need to be fabbed to fit since most out there appear to be 2.25 or 2.5?

[07tundra]

Originally Posted by superbang

The xpipe didn't make it to much louder on my e90. Even with the full magnaflow exhaust.

http://www.e90post.com/forums/showthread.php?t=780900

Drop the cats and see what happens..lol

[Mit_Boost]

If you're on stock turbos, aftermarket exhaust are worthless. You'll maybe gain 5 WHP with a very minimal increase in spool. Save your money & worry about an exhaust after you've gone RB/VTTS2-S3/Single Turbo, when the exhaust will actually become a restriction.

[westchester335i]

^ Ok JEFF

I have the 2.5 installed, I got it for $60 on AA and I did the OEM exhaust mod and my exhaust sounds very nice.

[superbang]

Originally Posted by dlbrooks18

Interesting, so maybe not worth it would you say? Thanks.

If you're just looking for noise then id say not worth it. These cars have 4 cats. From what ive read, you can just throw on a set of catless downpipes bolted to the stock exhaust for some good noise and a nice bumpin power.

[Mit_Boost]

Originally Posted by westchester335i

^ Ok JEFF

I have the 2.5 installed, I got it for $60 on AA and I did the OEM exhaust mod and my exhaust sounds very nice.

Who's Jeff? I mean if you just want to change the sound, get a rear section, but that's all it'll do on a stock turbo car -- change the sound.


I have a 420 WHP PROtune N54, pump gas on COBB... Even the tuner agrees, on stock turbos I might see a 5 WHP gain by (which can be done for less that $100 by cutting out the cats and replacing them with resonators).

Here's a quick dyno video with the dynos comparing the Stock Baseline, 93 Octane ProTune & Straight E85 Tune

[BigHoncho]

Originally Posted by Mit_Boost

Who's Jeff? I mean if you just want to change the sound, get a rear section, but that's all it'll do on a stock turbo car -- change the sound.


I have a 420 WHP PROtune N54, pump gas on COBB... Even the tuner agrees, on stock turbos I might see a 5 WHP gain by (which can be done for less that $100 by cutting out the cats and replacing them with resonators).

Here's a quick dyno video with the dynos comparing the Stock Baseline, 93 Octane ProTune & Straight E85 Tune

Akrapovic claims 8HP on an Alpina E92 with just the rear muffler (slip-on)

[Mit_Boost]

Originally Posted by BigHoncho

Akrapovic claims 8HP on an Alpina E92 with just the rear muffler (slip-on)

Akrapovic is also a business & are charging over $2k for the Stainless Steel (or $3k for the Titanium) exhaust. So at 8 HP, you're paying about $250 per HP.