Does the Akra Evo always throw a CEL, /w race cats?

[The-Traveler]

I'm in Toronto and trying to decide on some mods. The car's a 2011 m3, and I'm wondering if saving up for the Evo is a good idea.

From what I gather with race cats and a tune 40hp is possible, plus a lighter battery and lighter exhaust ( and dieting ) it might be possible to save 100 pounds.

Here in Toronto they stopped doing emissions measurements, and merely do an OBD-II readiness check.

I'm guessing with a tune the car would pass, but is it always necessary?
Does it smell a lot with race cats?

[surlynkid]

You will need a tune to show the secondary cats as okay.

[Hujan]

You need a tune or a device to eliminate the CEL. The race cats occupy the place on the Akra system where the secondary cats were on the OEM system. There are no cats whatsoever between the two o2 sensors on each side. Thus, as far as the car is concerned your system is catless.

With a lightweight battery, you can easily save 100 lbs. The Akra drops ~53 lbs. and a good Lithium battery will drop about the same.

The smell, which is very minor, is only pleasant at initial startup when the cats haven't fully warmed up. It's very mild.

The Akra system is, IMO, the best system on the market for people wanting to maximize power, but wanting to keep the car very mild in terms of smell and sound.

[BPMSport]

No way around it with the Akra, even though it has cats, they aren't between the oxygen sensor bungs so the car sees no cats at all.

[anom3]

Worth mentioning...

I installed my Akra midpipe about 1500KM ago. Pretty much right away I installed your stage 2 tune.

I have yet to see the error code for the post cat o2 sensors pop up.

I understand your tune in essence disables the CEL for this code... But should I still be seeing the code under INPA / etc?

Originally Posted by Mike Benvo

No way around it with the Akra, even though it has cats, they aren't between the oxygen sensor bungs so the car sees no cats at all.

[The-Traveler]

So we had a big monthly Cars & Coffee event here today, and I met a guy with the Akrapovic slip-on. It sounded nice but he said he now doesn't like it, because after 3 and a half years it's started to drone.

I knew about the initial break-in period, but I had no idea it would degrade with time!

Has anyone heard of this before? I'm thinking I may go with the MPE instead?

[BPMSport]

Originally Posted by anom3

Worth mentioning...

I installed my Akra midpipe about 1500KM ago. Pretty much right away I installed your stage 2 tune.

I have yet to see the error code for the post cat o2 sensors pop up.

I understand your tune in essence disables the CEL for this code... But should I still be seeing the code under INPA / etc?

The Akra Evo has bungs for the rear sensors.. There is no reason to throw a fault code for them unless they are unplugged or have a damaged heater circuit.

The GT4 which does not have provisions for the rear sensors uses modified software to eliminate errors for the lack of rear sensors.

[anom3]

Ah.

So the infamous "increased emissions" message is not the result of a fault code but something separate from that?

I just thought that "increased emissions" would have thrown a code.

Originally Posted by Mike Benvo

The Akra Evo has bungs for the rear sensors.. There is no reason to throw a fault code for them unless they are unplugged or have a damaged heater circuit.

The GT4 which does not have provisions for the rear sensors uses modified software eliminate the lack of sensors plugged in.

[Froglet]

Originally Posted by The-Traveler

So we had a big monthly Cars & Coffee event here today, and I met a guy with the Akrapovic slip-on. It sounded nice but he said he now doesn't like it, because after 3 and a half years it's started to drone.

I knew about the initial break-in period, but I had no idea it would degrade with time!

Has anyone heard of this before? I'm thinking I may go with the MPE instead?

I have the full Evolution exhaust on an E90. It has been on there since day 1 (for 30000 miles now). I don't know if the sound has changed over time since I don't own the car since the beginning, but it does sometimes drone around the 4k rpm range especially if you mildly accelerate from 2k rpm to 5k or so. If you floor the pedal it goes right past 4k rpm without any drone.

[81bear]

I think it depends on what your definition of drone is... I have people refer to the deep bass sound at very low rpm as drone and I have others who say drone is something much worse and can give you a massive headache or make you feel sick in severe cases... I have the Akra Evo on my car and it does have a deep bass tone when you step on the gas at about 1800-2200 rpm. Above that it sounds totally normal. I'm local so if you want to hear it just PM...

[Froglet]

Originally Posted by Froglet

I have the full Evolution exhaust on an E90. It has been on there since day 1 (for 30000 miles now). I don't know if the sound has changed over time since I don't own the car since the beginning, but it does sometimes drone around the 4k rpm range especially if you mildly accelerate from 2k rpm to 5k or so. If you floor the pedal it goes right past 4k rpm without any drone.

I just did some research into what drone actually is and I don't think I have it. The sound I am referring to is more of a 'rattling' sound...