[CactusDweller]

I want a dual midpipe setup, from the videos I've watched I like the tone of a dual midpipe over a single. I've narrowed it down to Evolution Racewerks and Active Autowerke. It's hard to pick from listening to videos, and I think I've watched every video on YouTube and I've read through every thread I can find on the subject.

AA is equal length while ER is not. They both sound pretty similar in video. AA costs about twice as much. AA has one resonator or two, ER has a non-resonated option and a resonated option with two resonators.

Is there a noticeable difference in tone/rasp/noise level between the two brands? For anyone who has heard both in person, what is different about the two?

I'm planning on keeping the OEM downpipes and axleback. I'm trying to figure out if there is a difference in tone and volume that would justify the extra $1000 for the AA midpipe.

What midpipe do you recommend?

[mike@x-ph.com]

Tough choice, if you like the stock sound and want it louder, get the Evolution racewerks

The equal length is an excellent choice if you want to change the sound to a more aggressive tone.

I don't think rasp or drone would be an issue with either one if you get the resonated versions

[CactusDweller]

It's such a tough choice. I do like the stock sound on my friend's G87. I've watched and re-watched dozens of youtube videos of both exhausts and they're near indistinguishable. I might be happy with ER and save the difference for other mods.

[tom @ eas]

Originally Posted by CactusDweller

It's such a tough choice. I do like the stock sound on my friend's G87. I've watched and re-watched dozens of youtube videos of both exhausts and they're near indistinguishable. I might be happy with ER and save the difference for other mods.

Dual midpipes will outflow single if looking for real power down the road (larger turbos, port injection, etc) and save the $1000 for supporting mods.

We always have ER midpipes in stock when ready, shoot over a PM and I'll make it happen.

[Crazyotter]

Milltek 102mm single

👆

[tom @ eas]

Originally Posted by Crazyotter

Milltek 102mm single

��

2nd that choice on the single option, we always have Milltek 102mm Single midpipes in stock also.

[mike@x-ph.com]

Originally Posted by Crazyotter

Milltek 102mm single

👆

excellent option if you are looking for a clean sound with a deep midrange tone

[Dieselmd]

Originally Posted by tom @ eas

Dual midpipes will outflow single if looking for real power down the road (larger turbos, port injection, etc) and save the $1000 for supporting mods.

We always have ER midpipes in stock when ready, shoot over a PM and I'll make it happen.

Forgive me if this has been posted elsewhere but at what power level is the single considered restrictive over the equal length? Thanks.

[Crazyotter]

Originally Posted by Dieselmd

Forgive me if this has been posted elsewhere but at what power level is the single considered restrictive over the equal length? Thanks.

I’m not sure there’s a limit but I’ve seen 600+whp running singles

[tom @ eas]

Originally Posted by Dieselmd

Forgive me if this has been posted elsewhere but at what power level is the single considered restrictive over the equal length? Thanks.

Good question. Had a long discussion some time ago with ER about this when discussing single vs dual midpipes and here's what they said:

Originally Posted by Evolution Racewerks

I know the trend is for a single mid pipe because it makes the exhaust quieter and reduces droning but it does this by reducing exhaust flow. It’s like having a permanent exhaust silencer that the Japanese cars put into their mufflers to reduce flow/noise. The factory dual mid pipes are 2.75”. You would have to run a single 4” to match the factory flow capabilities of the stock mid pipes. Running a 4” single pipe would be terrible for ground clearance especially on a lowered car. Our dual midpipes are 3” and thus, we would need to run around a 4.25” pipe to match the same flow.

Our dual resonated midpipes are really quiet and like our non-resonated midpipes do not drone. I currently have our dual resonated midpipes on our M3 for testing and I personally can’t wait to go back to the non-resonated version cause it’s so quiet. You’ll see it’s as quiet as stock at idle and normal driving. With aggressive driving it gets a little bit louder than stock but still very much like stock. Being able to keep the exhaust quiet and not drone while being able to have higher flow capabilities than stock, there really isn’t a need for us to make a single pipe version.

Certainly going EL isn't providing any help on the flow side with the additional bends involved, but it sounds slightly better than stock. People might have different opinions on what is loud vs quiet, but dual will always provide more flow.

[Dieselmd]

Originally Posted by tom @ eas

Good question. Had a long discussion some time ago with ER about this when discussing single vs dual midpipes and here's what they said:



Certainly going EL isn't providing any help on the flow side with the additional bends involved, but it sounds slightly better than stock. People might have different opinions on what is loud vs quiet, but dual will always provide more flow.

Thanks for the response. Interesting comment about ground clearance going from a dual 3" to a single 4".

[comp]

I'd advise you to go read this thread I started and also the subsequent threads on the G80 forum about EL Midpipes - they are not all the same.

https://g87.bimmerpost.com/forums/sh....php?t=2158886

[CactusDweller]

Originally Posted by Crazyotter

Milltek 102mm single

👆

Funny comment for a thread specifically asking about dual midpipes. I prefer the tone from the dual pipe setups. It sounds more like what I'd expect from an inline 6.

For what it's worth I went with ER resonated. Found it on sale and added in their crossover pipe, still came in $700 less than AA. Counting down the days until my car is delivered now.

[Crazyotter]

Originally Posted by CactusDweller

Funny comment for a thread specifically asking about dual midpipes

You’re welcome 👍🏼

[Info@mad-us.com]

Originally Posted by Dieselmd

Forgive me if this has been posted elsewhere but at what power level is the single considered restrictive over the equal length? Thanks.

We have a few cars running our 3.5'' single with 950whp+ and at least 100 or so running e85 in the 700+ range.

El's are probably the last place you want to look when it comes to flow. X pipe and Singles have the advantage.

[Dieselmd]

Originally Posted by Info@mad-us.com

We have a few cars running our 3.5'' single with 950whp+ and at least 100 or so running e85 in the 700+ range.

El's are probably the last place you want to look when it comes to flow. X pipe and Singles have the advantage.

I know this is a BMW forum but I've seen a few high HP 2J's and RB26's with single 3" exhausts so they can't be a restriction. Again, I'll defer to engineers and those that have experimented with both.

[Info@mad-us.com]

Originally Posted by Dieselmd

I know this is a BMW forum but I've seen a few high HP 2J's and RB26's with single 3" exhausts so they can't be a restriction. Again, I'll defer to engineers and those that have experimented with both.

A single 3 inch system is probably good for around 650 whp.

The dual Y pipe /single midpipe design of these cars helps does help due to the venturi effect it creates.

With that said a 3.5'' starts hitting its limit around 900-1000 whp area. Anything more and you should start looking at 4 inch pipe options.

[Dieselmd]

Originally Posted by Info@mad-us.com

A single 3 inch system is probably good for around 650 whp.

The dual Y pipe /single midpipe design of these cars helps does help due to the venturi effect it creates.

With that said a 3.5'' starts hitting its limit around 900-1000 whp area. Anything more and you should start looking at 4 inch pipe options.

Sorry, I should have been more specific with my comparison in equal vs Single mid pipes. if a 3" single is good on high HP inline 6's, a 3.5" single should provide even more flow. So its hardly restrictive when trying to make high HP.

[Info@mad-us.com]

Originally Posted by Dieselmd

Sorry, I should have been more specific with my comparison in equal vs Single mid pipes. if a 3" single is good on high HP inline 6's, a 3.5" single should provide even more flow. So its hardly restrictive when trying to make high HP.

Correct, the 3.5 is more than enough for the avg modded s58 customer.

[mike@x-ph.com]

Originally Posted by CactusDweller

Funny comment for a thread specifically asking about dual midpipes. I prefer the tone from the dual pipe setups. It sounds more like what I'd expect from an inline 6.

For what it's worth I went with ER resonated. Found it on sale and added in their crossover pipe, still came in $700 less than AA. Counting down the days until my car is delivered now.

Congrats on the ER midpipe, you wont be disapointed

[Data Fox]

single 3.5 inch pipe calculates out to 1,029 CFM

dual 2.75 (stock) calculates out to 1,244 CFM

dual 2.75 is mathematically optimized (only regarding CFM) for 566HP before accounting for other factors like pulse width, VE and scavenging.

Remember, there are other factors to calculate for besides just CFM, but there isnt enough space here to type all that out.

[Info@mad-us.com]

Originally Posted by Data Fox

single 3.5 inch pipe calculates out to 1,029 CFM

dual 2.75 (stock) calculates out to 1,244 CFM

dual 2.75 is mathematically optimized (only regarding CFM) for 566HP before accounting for other factors like pulse width, VE and scavenging.

Remember, there are other factors to calculate for besides just CFM, but there isnt enough space here to type all that out.

Inner diameter tends to be a tad smaller but for comparison sake.

4 inch is roughly 14,445 cfm

For the 3.5 diameter I got 1,106 Radius is 1.75 squared 9.62 sq inches total.