Who is running downpipes?

[Gunzaro]

Anyone have any feedback? Easy to install?

[Vintage]

I am running the AR downpipes (ceramic coated with race cats) - I love them.

Local shop installed them and it took them four hours or so. The biggest challenge was finding a competent, independent, local shop that works on BMWs.

[Lambobimmer]

I am running Catless AR DP's. I installed them myself and I can get them on and off under an hour now. This is really a pretty easy job if you know what you are doing and if you have a lift.

Cobb is my favorite mod and the AR DP's would be 2nd. They are well crafted and fitament is perfect.

[Vintage]

Trey Cobb and I live about 5 houses apart - small world. He is a super nice guy but I have the ESS tune since it was one of the first quality tunes available. However, I agree, 1) a good tune (Cobb or ESS), 2) DPs, and I would then add the third and fourth 3) Michelin PSS, and 4) FMIC.

[Hujan]

I'm not, but will be soon. AR for sure. Either going catless or with resonators. I will keep the rest of the exhaust stock.

After playing with exhausts on the M3, I've come to two conclusions:

(1) I am way too sensitive to drone/volume to use aftermarket mufflers, even the supposedly mild ones; and

(2) Replacing the primary cats with catless downpipes/test pipes (while keeping everything else stock) provides 90% of the gain of a full exhaust, with an absolutely minimal difference to the volume

The only other thing I'll do is swap out the tips.

[CedarZ4]

Originally Posted by Hujan

I'm not, but will be soon. AR for sure. Either going catless or with resonators. I will keep the rest of the exhaust stock.

After playing with exhausts on the M3, I've come to two conclusions:

(1) I am way too sensitive to drone/volume to use aftermarket mufflers, even the supposedly mild ones; and

(2) Replacing the primary cats with catless downpipes/test pipes (while keeping everything else stock) provides 90% of the gain of a full exhaust, with an absolutely minimal difference to the volume

The only other thing I'll do is swap out the tips.

I'm very sensitive to drone as well, which is a main reason I haven't jumped onto an aftermarket exhaust system yet. However, correct me if I'm wrong but isn't the whole point of an aftermarket exhaust for the increase in volume/throatier note? The gain is so minimal, 10-15 HP with a quality exhaust, especially when you take into consideration the $1,000 price tag of the AR DP (or few thousand for full exhaust system). Wouldn't a piggyback or ECU flash be much more sensitive if power gain is all that are you looking for?

That, or this is a cheap and easy way for 50+ HP gain, at minimum



Sorry… I had to.

[Vintage]

agree - buy a quality tune and DPs; skip the exhaust (Eisenmann was $3k plus installation). that is what I would have done if it were available at the time. instead, started with Eisenmann and had to wait almost a year for a tune to come out and then another two years for DPs to be available - now we have them all but the exhaust is unneccesary.

[Gunzaro]

Are the catted ones harder to install or something?

[Vintage]

I doubt it - maybe I was just taken, which would not be the first time!

[Hujan]

Originally Posted by CedarZ4

I'm very sensitive to drone as well, which is a main reason I haven't jumped onto an aftermarket exhaust system yet. However, correct me if I'm wrong but isn't the whole point of an aftermarket exhaust for the increase in volume/throatier note? The gain is so minimal, 10-15 HP with a quality exhaust, especially when you take into consideration the $1,000 price tag of the AR DP (or few thousand for full exhaust system). Wouldn't a piggyback or ECU flash be much more sensitive if power gain is all that are you looking for?

Generally that's true, especially for the Z4. I can't think if a full turbo-back exhaust system for the Z4.

But on the M3, there are many and I was fooled into thinking that the Akrapovic (which is akin to a turbo-back system for the Z4) would be quiet and drone free with all the benefits of a full system (no primary cats, high-flow secondary cats). In fairness, it is very mild from the outside and not bad in cabin for the most part, but it had enough to make me switch it out.

I used to feel that removing primary cats was useless without also removing the secondary cats. I now know better and feel that secondary cats do not rob much power, keep the exhaust from giving off too much smell, and keep the sound/rasp in check.

At the moment I have catless test pipes (essentially catless downpipes) with the rest of the exhaust stock on my M3. It's ideal for me. Will look to do the same to the Z4.

[DKZTT]

Installed the AR with race cats myself took me 6 hours lying on my back. Probaly much easier if I had a lift. Install was easy but have to be patient with tight space especially when removing the O2 sensors and putting them back on.