[PresidentEvil]

Hi, was watching this video of the M2 with straight piped exhaust

I've heard this term straight pipe many time but don't know exactly 100% what it is.


Is it just the entire exhaust replaced with a single pipe or does it still have the catalytic convertor?


The video is titled "M-Performance Straight Pipe", what does that mean?


Is it just the M Performance exhaust with the cat/resonator deleted but kept the muffler?


Will exhaust shops install them?

[CalAcacian]

A true straight pipe means only open tubing from the cylinders (or turbo(s)) back to the exit. No cat, no resonator, no muffler. Almost any shop will do this for you, some very rare ones may make you sign a waiver acknowledging that the system is intended only for off-road use. They're illegal for road use and won't pass a visual inspection or smog test unless you use a test station willing to provide fake passes.

If you are asking this question, then you should not be straight piping your car at this time. You are opening yourself up to a lot of potential issues that you don't yet understand.

[PresidentEvil]

Originally Posted by CalAcacian

A true straight pipe means only open tubing from the cylinders (or turbo(s)) back to the exit. No cat, no resonator, no muffler. Almost any shop will do this for you, some very rare ones may make you sign a waiver acknowledging that the system is intended only for off-road use. They're illegal for road use and won't pass a visual inspection or smog test unless you use a test station willing to provide fake passes.

If you are asking this question, then you should not be straight piping your car at this time. You are opening yourself up to a lot of potential issues that you don't yet understand.

thanks for the explanation, but the county I live in doesnt require any smog/emissions testing like other places

[mr_lab_rat]

It can mean either - straight pipe from the turbo or from the cat. Just no resonators or mufflers.

The video title is misleading. MPE has 4 outlets and two of them always go through the muffler regardless of the remotely controlled flap position.

[AndrewC1989]

Originally Posted by PresidentEvil

thanks for the explanation, but the county I live in doesn't require any smog/emissions testing like other places

Even so, a sport cat is a better idea. Little pricier, but totally worthwhile. No smells or CEL's (if it's high quality) and you still get a great sound (they actually sound better in my opinion, just not as loud obviously). I have a fabspeed/HJS 200 cell and have had 0 issues over 4 years.

[CalAcacian]

Originally Posted by PresidentEvil

thanks for the explanation, but the county I live in does require any smog/emissions testing like other places

Beyond smog/emissions testing, your can still be cited for not having the required emissions control devices on the car. Depending on where you take the car, it can even be impounded or destroyed.

You will have to code out errors or drive with a CEL because the O2 sensors will be getting readings outside of the anticipated range.

Your car will get pretty dirty with soot near the exhaust pipe.

Your car will smell bad as it runs, and sitting in slow or stopped traffic may become uncomfortable as you sit in toxic fumes.

Your car may, if fully straight piped, shoot flames out the rear and be a literal beacon for police to stop you.

Your car will be extremely loud, be ready to set off car alarms in parking garages and have pissed off neighbors.

If you are ready for all that, then go ahead, but make sure you fully understand what you are getting into first. I absolutely loved my straight piped 3000GT, but it definitely altered how I used the car. Just make sure you know what you are getting into first.

[VisualEcho]

Originally Posted by PresidentEvil

thanks for the explanation, but the county I live in does require any smog/emissions testing like other places

Being 100% honest, the sound (in real life) of a straight-piped M2 isn't appealing at any time other than fully on it...from a distance.

If you don't do the sport cat for the environment, do it for the sound, as it's sooooo much more warm and throaty. No cat means bright rasp, and it's pretty harsh and terrible sounding actually (to my ear), even with a muffler. Without a muffler it's just plain atrocious.

[PresidentEvil]

Originally Posted by mr_lab_rat

It can mean either - straight pipe from the turbo or from the cat. Just no resonators or mufflers.

The video title is misleading. MPE has 4 outlets and two of them always go through the muffler regardless of the remotely controlled flap position.

Originally Posted by AndrewC1989

Even so, a sport cat is a better idea. Little pricier, but totally worthwhile. No smells or CEL's (if it's high quality) and you still get a great sound (they actually sound better in my opinion, just not as loud obviously). I have a fabspeed/HJS 200 cell and have had 0 issues over 4 years.

Originally Posted by CalAcacian

Beyond smog/emissions testing, your can still be cited for not having the required emissions control devices on the car. Depending on where you take the car, it can even be impounded or destroyed.

You will have to code out errors or drive with a CEL because the O2 sensors will be getting readings outside of the anticipated range.

Your car will get pretty dirty with soot near the exhaust pipe.

Your car will smell bad as it runs, and sitting in slow or stopped traffic may become uncomfortable as you sit in toxic fumes.

Your car may, if fully straight piped, shoot flames out the rear and be a literal beacon for police to stop you.

Your car will be extremely loud, be ready to set off car alarms in parking garages and have pissed off neighbors.

If you are ready for all that, then go ahead, but make sure you fully understand what you are getting into first. I absolutely loved my straight piped 3000GT, but it definitely altered how I used the car. Just make sure you know what you are getting into first.

Originally Posted by VisualEcho

Being 100% honest, the sound (in real life) of a straight-piped M2 isn't appealing at any time other than fully on it...from a distance.

If you don't do the sport cat for the environment, do it for the sound, as it's sooooo much more warm and throaty. No cat means bright rasp, and it's pretty harsh and terrible sounding actually (to my ear), even with a muffler. Without a muffler it's just plain atrocious.

thank you for the infos, that is a real eye opener I didn't know they would cause that many issues.

I just want the exhaust to sound a little bit more loud and pronounced, maybe I will get a sport cat

[VisualEcho]

Originally Posted by PresidentEvil

I just want the exhaust to sound a little bit more loud and pronounced, maybe I will get a sport cat

The sport cat has such a great effect on the exhaust that a lot of guys that get it don't even bother with an exhaust afterwards.

If it's not enough, I suggest the Dinan resonator delete next. It's what I run, and I'm very happy with it.

I bought both pieces (Fabspeeds sport cat [no CEL], and resonator delete) used for $1150 and it cost me only $100 to put them on, so $1250 out the door IIRC, and it's fantastic.

[AndrewC1989]

Originally Posted by PresidentEvil

I just want the exhaust to sound a little bit more loud and pronounced

Originally Posted by VisualEcho

The sport cat has such a great effect on the exhaust that a lot of guys that get it don't even bother with an exhaust afterwards.

If it's not enough, I suggest the Dinan resonator delete next. It's what I run, and I'm very happy with it.

Fabspeed Sportcat + Dinan Resonator Delete https://f87.bimmerpost.com/forums/sh....php?t=1355352