Best Section 2 for power

[erickhoyos]

This is something that I’ve been wondering for a while. I know stock section 2 is good on its own but I want to know if there are better options to make equal or better power. I’m on the road to install basic bolt ons, so far I have Megan catless headers, SGT unresonated sect 1, performance air filter, and Manzo muffler (lol). Untuned but waiting for better mods for a proper tune.

[Nihilation]

Interested as well. Of curiosity, did you run different studs with the Megan headers? About to install mine.

[mrgizmo04]

SS 2.5 dual seemed to be popular on the old forum. I think Obioban noticed a bump (butt dyno). I did on my setup as well, although never dynoed.

On my setup - ssv1, ss racing cats, [s2], ss sport, it seemed to breathe better/easier with SS 2.5 dual. I know a lot of exhaust setup is sometimes in search of the perfect sound, so if you are a rasp lover you will be disappointed, as SS 2.5 dual basically eliminated it from my setup. It sounded awesome (to my ears from the driver's seat) with the stock s2.

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[eacmen]

Bimmerworld race. Its loud but obnoxious.


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[erickhoyos]

Interested as well. Of curiosity, did you run different studs with the Megan headers? About to install mine.

I remember I asked the shop that installed them to use E36 studs since sometimes OEM studs don’t work well but I don’t think they did since fitment was spot on from what they told me. The only issue was that the secondary O2 sensor bungs were out of place so they couldn’t install them.

[Darbshaw]

I remember I asked the shop that installed them to use E36 studs since sometimes OEM studs don’t work well but I don’t think they did since fitment was spot on from what they told me. The only issue was that the secondary O2 sensor bungs were out of place so they couldn’t install them.

I can attest to this, I just recently went with Megan headers and I had 0 issues on install. Reused most my old studs because I was tired and lazy to get them all out.

Zero fitment issues and my secondary o2’s are capped so that wasn’t an issue there. Although I did have to find my own cap for the EGR.

Huge improvement on the butt dyno as well moving to the Megan headers. Worth every little bit of time.

[erickhoyos]

SS 2.5 dual seemed to be popular on the old forum. I think Obioban noticed a bump (butt dyno). I did on my setup as well, although never dynoed.

On my setup - ssv1, ss racing cats, [s2], ss sport, it seemed to breathe better/easier with SS 2.5 dual. I know a lot of exhaust setup is sometimes in search of the perfect sound, so if you are a rasp lover you will be disappointed, as SS 2.5 dual basically eliminated it from my setup. It sounded awesome (to my ears from the driver's seat) with the stock s2.

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I was reading Obioban’s review on the SS resonated sect 2 just now. TboneM3 input his review as well and said that he didn’t feel any major difference between stock and SS other than he felt there was better midrange power. I guess it’s subjective due to choice of mods. I’m just trying to achieve as much power as possible without having to dish out cash for cams, CSL intake, or forced induction.

[Seattleswimboy]

For top peak HP the rouge engineering section 2 with electronic dump is the best out there while keeping the standard quad tail pipes. The ability to bypass the muffler gives a preppy decent bump. Most dynos I have seen have been about +10hp

[Obioban]

There's two significant factors:
1) total pipe area
2) merge location

For (1), you only need enough that's it not a restriction. Swapping out the section 2 on a car with/near stock power isn't going to get you anything. Cheat sheet above. Stock is ~2.25" (dual).
For (2), the stock location is pretty optimal for 99% of people-- really good top end power with great low/mid range power. You have to be will to throw away the sub 5000rpm power band to gain anything at the top.

I like the SS twin 2.5" section 2 because it keeps the stock merge location, so it doesn't ruin to bottom end/mid range, which still flowing sufficiently for a full bolt on car (and then some). It also allow you to use a resonator, which nixes the rasp (which I dislike).

[Obioban]

For top peak HP the rouge engineering section 2 with electronic dump is the best out there while keeping the standard quad tail pipes. The ability to bypass the muffler gives a preppy decent bump. Most dynos I have seen have been about +10hp

eh...

The stock muffler has creates no restriction at/near stock power levels-- you won't gain anything by bypassing it.

If you have a significantly more powerful than stock car, most people have bumped the muffler up to something that flows to match-- at which point a theoretical dump valve also provides no benefit.

The RE section 2 is a 76mm pipe specifically, which is slightly smaller than 3"-- so it actually flows worse than stock... and that's before the dump valve, which makes me think it never has any power benefit.

If there's a dyno showing it making 10hp, I'd guess it was before the Rogue Engineering El Diable muffler-- the original design of that thing was probably the most power killing muffler for the chassis.

[erickhoyos]

There's two significant factors:
1) total pipe area
2) merge location

For (1), you only need enough that's it not a restriction. Swapping out the section 2 on a car with/near stock power isn't going to get you anything. Cheat sheet above. Stock is ~2.25" (dual).
For (2), the stock location is pretty optimal for 99% of people-- really good top end power with great low/mid range power. You have to be will to throw away the sub 5000rpm power band to gain anything at the top.

I like the SS twin 2.5" section 2 because it keeps the stock merge location, so it doesn't ruin to bottom end/mid range, which stiff flowing sufficiently for a full bolt on car (and then some). It also allow you to use a resonator, which nixes the rasp (which I dislike).

Will an X pipe gain similar results or worsen low/mid range since the diameter of the pipe merges from 2.25 to 3 back to 2.25? Wouldn’t that create a bottleneck effect?

[SWRT_M3]

Will an X pipe gain similar results or worsen low/mid range since the diameter of the pipe merges from 2.25 to 3 back to 2.25? Wouldn’t that create a bottleneck effect?

Depends on what you consider to be an "X pipe"...

The so called "2-1-2 x pipe" Section 2s are not a true x pipe. They are closer to a " Y " pipe than a true "X pipe".

Now the Z4M and the e9x have a proper X pipe (section).

I would stick with the OE Section 2 till the 330+ RWHP.

[Obioban]

I feel like the crossover to when it starts to be beneficial is more like 310-320rwhp (sae dynojet).