[CdnE90]

What's everyones thoughts on the reliability of aftermarket cat-less downpipes for use on the track (road, not drag)?

I was thinking about this and the heat that a tracked car produces is likely exceptionally greater than a normally driven street car, no matter how fast somebody wants to drive through a set of "twisties".

There's a video on the internet here of the turbo on the N54 heating up red-hot, and on a road course this heat-up, cool-down cycle would be repeated at every corner. On the road course that I go to, that's 20 turns, and after a 20min stint on the track, the downpipes would cycle from extreme temps to normal temps 140 times, or more than 400 times per track day.

Or does the lack of cat converter in the downpipe help with getting that heat out and actually help prolong the life of the turbos and downpipes?

[JoosyJoos]

The red glowing N54 picture you've seen is BMW's stress test they do when evaluating engines. If I remember correctly they are run flat out for something like a full day or until failure. Unless you're really extreme I don't see that happening lol.

I think you'll be fine assuming you buy a quality set of downpipes. Its likely to be the same grade of material as OEM. Additionally, without a catalytic converter and if you get the new DP ceramic coated you will actually see lower engine temperatures because the efficiency of the gases being pushed out the exhausted is better.

[M3E46M]

I'm actually searching for a good set, ceramic coated and plan to track mine any good ones out there that you recommend?

[themyst]

AR design if money is not an issue, but all of the available downpipes have no reported issues with reliability.

edit - the UR downpipes rusted according to one user (jpsimon?)

[Belarus]

Originally Posted by themyst

AR design if money is not an issue, but all of the available downpipes have no reported issues with reliability.

edit - the UR downpipes rusted according to one user (jpsimon?)

+1, also Macht Schnell get very positive feedback.

[david @ eas]

Originally Posted by Belarus

+1, also Macht Schnell get very positive feedback.

Just took our 135i on the track during Mfest... I had a total of 6-7 Sessions in the car that lasted 25 minutes each and one session that lasted 35 minutes. Nothing went wrong on the car, everything performed as it should, and more importantly the downpipes, are still solid with no cracks or leaks.

The Macht Schnell Thermal Coated DP's really held up and performed.