REVIEW: Bypass OEM Exhaust Mod

[zibawal]

Do u need re solder?

[2K7]

Originally Posted by zibawal

Do u need re solder?

yes

[acechardukian]

When you bypass the center chamber like that are you getting any O2 sensor issues or SES light pop-ups? Or is there essentially nothing changing? The shop I went to was telling me I may have sensor problems doing it...but I haven't read about anyone having these issues after doing this particular mod.

[dagolfpro]

Originally Posted by acechardukian

When you bypass the center chamber like that are you getting any O2 sensor issues or SES light pop-ups? Or is there essentially nothing changing? The shop I went to was telling me I may have sensor problems doing it...but I haven't read about anyone having these issues after doing this particular mod.

Zero issues.

[1SerieStud]

Love both methods, but I'm partial to the perforated pipe replacement mod, instead of the straight through mod. The former reminds me of the MPE (which I had on my prior e90 M3) but with more bite to it. The latter sounds more American V8-ish.

I just finished coating my modded OEM exhaust and I'm thinking I'll swap it before the end of the week…can't wait to give my car a new voice!

[MKidd]

how much did they charge to do this at Bimmersport..? im thinking of taking my M3 there too.

[JDM_CL9]

Originally Posted by Yasin

how much did they charge to do this at Bimmersport..? im thinking of taking my M3 there too.

Might want to just give them a call since the original poster had this done in 2012.

Bimmersport Automotive Inc
(905) 670-9200

[N1tr0gen]

Hands down the best thing you can do first to a car ) The sound is amazing and only gets better imho, driving mine after a couple months in a beater is just music )))

[MKidd]

Originally Posted by JDM_CL9

Might want to just give them a call since the original poster had this done in 2012.

Bimmersport Automotive Inc
(905) 670-9200

Will do, thanks a lot; i actually didn't take into consideration the the OPs post date lol.

[ryank382]

sorry for bringing back and old thread but i just have 1 question. Wouldnt it be easier to just cut the muffler off and straight pipe it out the back? why bother opening up the muffler? Am i missing something?

[1SerieStud]

Originally Posted by ryank382

sorry for bringing back and old thread but i just have 1 question. Wouldnt it be easier to just cut the muffler off and straight pipe it out the back? why bother opening up the muffler? Am i missing something?

Yes, you're missing the fact that if you do what you suggested, your exhaust will drone to no end and you will have managed to turn the interior sound of a fine machine into what a Honda Civic with a fart can sounds like - inside the cabin. Exterior sound may be attractive, but the drone will be unbearable if your ears are any sensitive at all.

The muffler mod does not drone - I'm very particular and have a 0 drone tolerance, so I can vouch for this process.

[ryank382]

Originally Posted by 1SerieStud

Yes, you're missing the fact that if you do what you suggested, your exhaust will drone to no end and you will have managed to turn the interior sound of a fine machine into what a Honda Civic with a fart can sounds like - inside the cabin. Exterior sound may be attractive, but the drone will be unbearable if your ears are any sensitive at all.

The muffler mod does not drone - I'm very particular and have a 0 drone tolerance, so I can vouch for this process.

Thanks for the quick reply. Why is that the case though? the sound is muffled in the center chamber normally but with this mod the exhaust is straightpiped straight through. im trying to understand what the difference is physically and why it would have no drone this way. maybe i am understanding the pictures wrong

[1SerieStud]

Originally Posted by ryank382

Thanks for the quick reply. Why is that the case though? the sound is muffled in the center chamber normally but with this mod the exhaust is straightpiped straight through. im trying to understand what the difference is physically and why it would have no drone this way. maybe i am understanding the pictures wrong

No problem! Even though the pipes with perforations are replaced by solid pipes for a straight-through design, the density of the muffler unit plus the fiber glass continue to absorbe the resonance, which is what translates into drone. Also, there is a second set of unperforated pipes that most people leave alone, and I'm sure they do their part in the muffling process. I personally had the fiber glass put back into the chambers after the piping was replaced; some people choose to leave it out, as apparently there is enough material to compensate for resonance - I didn't want to gamble with this as I can't stand exhausts that drone and the fiber glass weighs next to nothing and is easy to push back in.

Straight pipes, and even some exhausts that have mufflers (smaller ones) have a tendency to drone in the lower rpm's.

I hope this helps!

[ryank382]

Originally Posted by 1SerieStud

No problem! Even though the pipes with perforations are replaced by solid pipes for a straight-through design, the density of the muffler unit plus the fiber glass continue to absorbe the resonance, which is what translates into drone. Also, there is a second set of unperforated pipes that most people leave alone, and I'm sure they do their part in the muffling process. I personally had the fiber glass put back into the chambers after the piping was replaced; some people choose to leave it out, as apparently there is enough material to compensate for resonance - I didn't want to gamble with this as I can't stand exhausts that drone and the fiber glass weighs next to nothing and is easy to push back in.

Straight pipes, and even some exhausts that have mufflers (smaller ones) have a tendency to drone in the lower rpm's.

I hope this helps!

Definitely helps thank you. Do you mean that sound still escapes from the unperforated straight pipes? i also forgot about the first small chamber as well lol

[1SerieStud]

Originally Posted by ryank382

Definitely helps thank you. Do you mean that sound still escapes from the unperforated straight pipes? i also forgot about the first small chamber as well lol

It doesn't "escape" per se if the weld job is done properly; however, sound waves are transmitted/conducted.

[ryank382]

Originally Posted by 1SerieStud

It doesn't "escape" per se if the weld job is done properly; however, sound waves are transmitted/conducted.

Understood thanks

[M3ANMACHINE]

does anyone happen to know the dB level of the bypass mod with the rest of the car stock?

[Ultra M]

does this add more horse power by any chance and is there any negative sides to it ?

[jgbedford]

Hi everyone,

I too am thinking about the full bypass mod. I took it to a local shop and they told me that this method is not recommended for the V8 BMW's, that it reduces too much back pressure, and he said something about the computer senses through the oxygen sensor calling for a lean mixture. He said that this ultimately reduces power and could damage engine internals with worst case burnt plugs and valves.

Is this true? I don't want to dice up my OEM exhaust and run into trouble.

Maybe I got a bad shop, that ultimately didn't have the talent or time to do this mod... who knows.

Thanks!

[Stunnerable]

Originally Posted by Jbedford

Hi everyone,

I too am thinking about the full bypass mod. I took it to a local shop and they told me that this method is not recommended for the V8 BMW's, that it reduces too much back pressure, and he said something about the computer senses through the oxygen sensor calling for a lean mixture. He said that this ultimately reduces power and could damage engine internals with worst case burnt plugs and valves.

Is this true? I don't want to dice up my OEM exhaust and run into trouble.

Maybe I got a bad shop, that ultimately didn't have the talent or time to do this mod... who knows.

Thanks!

Ugh.. This post is almost a year old but I have to respond. The back pressure myth is just that, a myth! What you need to do is get a good tune on your car after the exhaust mod. That's all. This is one of the best bang for buck mods you can do to this car. I hope you made out well!

[Millie]

Originally Posted by Jbedford

He said that this ultimately reduces power and could damage engine internals with worst case burnt plugs and valves

[Thik]

Originally Posted by Jbedford

Hi everyone,

I too am thinking about the full bypass mod. I took it to a local shop and they told me that this method is not recommended for the V8 BMW's, that it reduces too much back pressure, and he said something about the computer senses through the oxygen sensor calling for a lean mixture. He said that this ultimately reduces power and could damage engine internals with worst case burnt plugs and valves.

Is this true? I don't want to dice up my OEM exhaust and run into trouble.

Maybe I got a bad shop, that ultimately didn't have the talent or time to do this mod... who knows.

Thanks!

Which shop was this?