Exhaust recommendations

[cplay4me]

I've been searching and reading through exhaust threads and articles online covering exhaust mods for e92 M3s for the last couple of weeks. I'm feeling a bit stumped and hoping I can get some situation-specific input.

I've got a 2012 e92 M3 that I'm looking to change the exhaust on. I'd like the most power benefit I can get without getting any exhaust smell in the car. When I purchased it, the car had an IPE valvetronic exhaust with no cats and the smell was nasty (plus, I have to pass emissions).

So, what's the path here? Do I just need to get an x pipe with high-flow cats? From what I've read it's the first set of cats that create the most restriction--are there high-flow versions of those that I can purchase? Should I change all 4 to HF?

Appreciate the help!

[randrews15]

You have options but sounds limited. I don't know if 4 HFCs will get rid of the smell that some have. I'm running a full Akra setup and there is little bit of a smell until the cats warm up; however, I don't have to deal with emissions down here. You may want to look at the challenges line up of new x-pipes. They have one that deletes the secondary cats and retains the primaries. Smell is not an issue and it would allow you to pass emissions I do believe.

[cplay4me]

Thanks for the reply. Couple of questions:

Does the full akra setup maintain all the cats?
If I used Macht Scnell test pipes, would those stink and could I simply reattach the primary cats when needed for emissions?

I don’t have a problem with a little smell on warm-up. I just don’t want to be stopped at a light and have it building up in the car or smell it while I’m driving.

[wfdeacon88]

Originally Posted by cplay4me

Thanks for the reply. Couple of questions:

Does the full akra setup maintain all the cats?
If I used Macht Scnell test pipes, would those stink and could I simply reattach the primary cats when needed for emissions?

I don’t have a problem with a little smell on warm-up. I just don’t want to be stopped at a light and have it building up in the car or smell it while I’m driving.

I have rogue test pipes, retaining secondaries, paired with a Corsa. The smell is very limited, only if you stand behind the car will you smell anything, and it's not like catless. Driving, no smell. I kept the primary cats for inspection. Haven't had mine yet, but that's my plan to reattach and tune back to stage 1.

[randrews15]

Originally Posted by cplay4me

Thanks for the reply. Couple of questions:

Does the full akra setup maintain all the cats?
If I used Macht Scnell test pipes, would those stink and could I simply reattach the primary cats when needed for emissions?

I don’t have a problem with a little smell on warm-up. I just don’t want to be stopped at a light and have it building up in the car or smell it while I’m driving.

Full Akra eliminates the cats and puts a pair of 200 cell HFCs where the secondary cats were. The smell isn't bad and mainly when you're still. Even with the top down I hardly notice it. With the top up and air on I don't even get a hint of it. If you have emissions testing you'll likely need to swap it out for the stock setup for inspection. But, I have heard of people passing it with the Akra setup, so that depends on the testing in your area. Macht snell is a nice pipe from what I've heard and can be paired with a lot of rear sections.

[cplay4me]

Originally Posted by randrews15

Full Akra eliminates the cats and puts a pair of 200 cell HFCs where the secondary cats were. The smell isn't bad and mainly when you're still. Even with the top down I hardly notice it. With the top up and air on I don't even get a hint of it. If you have emissions testing you'll likely need to swap it out for the stock setup for inspection. But, I have heard of people passing it with the Akra setup, so that depends on the testing in your area. Macht snell is a nice pipe from what I've heard and can be paired with a lot of rear sections.

Appreciate the info, thanks. They do an OBDII test for emissions where I am, so I just need to get through that.

[cplay4me]

Originally Posted by wfdeacon88

I have rogue test pipes, retaining secondaries, paired with a Corsa. The smell is very limited, only if you stand behind the car will you smell anything, and it's not like catless. Driving, no smell. I kept the primary cats for inspection. Haven't had mine yet, but that's my plan to reattach and tune back to stage 1.

Great appreciate the input!

[randrews15]

Originally Posted by cplay4me

Appreciate the info, thanks. They do an OBDII test for emissions where I am, so I just need to get through that.

If you go with HFC you will likely need to tune out the CEL or you'll get the increased emissions light.

[cplay4me]

Originally Posted by randrews15

If you go with HFC you will likely need to tune out the CEL or you'll get the increased emissions light.

Yeah I figured that would be the case. Although the challenge site says the Sport pipe won't require a tune for CEL.

I'm actually debating at this point about just saving the money and doing an SC. Part of me really doesn't want to do FI on such a great N/A engine, but....

[randrews15]

Originally Posted by cplay4me

Yeah I figured that would be the case. Although the challenge site says the Sport pipe won't require a tune for CEL.

I'm actually debating at this point about just saving the money and doing an SC. Part of me really doesn't want to do FI on such a great N/A engine, but....

The sport pipe only gets rid of the secondary cats so that's why it is able to not throw a CEL. An exhaust and a sc combo would bring the car to the next level for sure. Check the forums as there are some good deals on occasion for a nice used system.

[cplay4me]

Appreciate it--I'm looking around now. Decided to keep the car NA for now. Maybe SC down the road.

[SAMM3Y]

Originally Posted by randrews15

Full Akra eliminates the cats and puts a pair of 200 cell HFCs where the secondary cats were. The smell isn't bad and mainly when you're still. Even with the top down I hardly notice it. With the top up and air on I don't even get a hint of it. If you have emissions testing you'll likely need to swap it out for the stock setup for inspection. But, I have heard of people passing it with the Akra setup, so that depends on the testing in your area. Macht snell is a nice pipe from what I've heard and can be paired with a lot of rear sections.

I'm pretty sure the cats on the akra are 100 cell

[cplay4me]

I think that's correct. The only 200 I've found was the challenge pipe that I can't buy anymore unless used.

[SAMM3Y]

Originally Posted by cplay4me

I think that's correct. The only 200 I've found was the challenge pipe that I can't buy anymore unless used.

200 is the norm for most hfc's they're metallic too I believe.. 100 cell per square inch are less restrictive, they're metallic and made of some exotic materials like platinum, palladium and rhodium.. nice stuff.. that's why they're expensive.

What kind of car do you have op, what's the color?

[cplay4me]

White 2012 e92

[Montaver]

The Evolve HFC X-Pipe has 200 cell cats, I'd probably go for that. You can also buy new challenge pipes from IND as they brought them back. There are loads of other options for HFC, Gintani, ESS etc.

[SAMM3Y]

Evolve stuff is made by supersprint and is really nice stuff.. I'm selling a supersprint system but it's catless.. I'd part with the muffler only though if your interested. Pm me

[cplay4me]

What would you want for the supersprint muffler shipped to 97504?

[kevin @ eas]

If OR smog is anything like CA smog tests most of the mentioned setup will not work unless you have a tune. This is because most sport x-pipe put the cats in where the secondary cats usually go. Leaving the primary o2 sensor locations getting catless readings. A Tune will turn off the catless monitor and the secondary o2 sensor which leaves 1 or 2 monitors not ready. OR might allow for 1 monitor not to be ready but if both cat and secondary o2 are not ready you might have issues.

The RKP street x-pipe will work since it uses the primary cats and deletes the monitored secondary cat. Ess used to make a high flow x-pipe with the cats in the primary location but doesnt anymore. AFE is the only one I know that makes a high flow catted x-pipe with the cats in the correct location.

[cplay4me]

Got it. I planned to swap back to stock for the emissions test. It's only every 2 years and I am going to get it done here in the next few weeks.

What I'm really running into is that I don't want something that smells. I'm unfortunately fairly sensitive to that.

That being said, when I bought the car, it had a catless IPE system on it. It wasn't pleasant but I could def. drive it--unlike the old STI that I put a catless downpipe on....Blech. I switched to a high-flow cat pipe though and had no issues.

So, the real question here is that I don't know if removing some of the cats and switching to HFCs will cause a smell that bugs me. I have found 0 cost-effective solutions so far where all cats are switched to HF. That leaves me thinking the best option might be to get a used pipe with high-flow secondaries and see how the smell is for me.

I do stop-n-go driving and don't want to smell it in the car when I have the windows down in traffic.

[kevin @ eas]

Originally Posted by cplay4me

Got it. I planned to swap back to stock for the emissions test. It's only every 2 years and I am going to get it done here in the next few weeks.

What I'm really running into is that I don't want something that smells. I'm unfortunately fairly sensitive to that.

That being said, when I bought the car, it had a catless IPE system on it. It wasn't pleasant but I could def. drive it--unlike the old STI that I put a catless downpipe on....Blech. I switched to a high-flow cat pipe though and had no issues.

So, the real question here is that I don't know if removing some of the cats and switching to HFCs will cause a smell that bugs me. I have found 0 cost-effective solutions so far where all cats are switched to HF. That leaves me thinking the best option might be to get a used pipe with high-flow secondaries and see how the smell is for me.

I do stop-n-go driving and don't want to smell it in the car when I have the windows down in traffic.

Oh I see, test pipes are a pretty good option that are cost effective. The secondary cats are 200 cell so is about the same as doing a high flow catted x-pipe. I have test pipes on mine and the gas smell is no where near extreme as full catless.

[SAMM3Y]

Pm'd