[blitzyo]

I'm looking at adding a catted DP to my non-OPF M2C with stock exhaust and stock tune (warranty).

Narrowed down to two downpipes with HJS cats:
- https://www.lightweight-performance....ren-p198196237
- https://www.manhart-performance.de/s...tic-converters

I don't trust non HJS cats to give me long life and no CELs.
Wondering if its worth it, because they are quite expensive for what they are. I'm looking for a slight increase in sound and power, but without the added smell and CEL of catless DP.

Not considering any exhaust systems, as only the Akra and MPE sound nice to me and they both cost around 5k usd where I live. The full Akra with linkpipe costs even more!

[Megator]

Why? like without a tune the benefit will be minimal. Turbo spool might be marginally faster but boost targets will stay the same.

But yeah HJS cats would keep you legal in most places.

EDIT: BTW modern ECUs target torque not AFRs so hardware changes barely affect power without an acompanying tune.

[SEAT TIME RULES]

I've run performance 100, or 200 CEL HFC's on a EVO X and now on my M2C.

You will throw a code with any HFC below 300 CEL IMHO.

You can clear the P0420 code just before taking it in for a sniffer test and as long as the code doesn't pop back up you should be fine w/o a tune. I ran the new cats w/o a tune for about 2 months. I could go about 75-100 miles before it would throw the code again. I have a AK Motion Display that allowed me to clear the code with just one touch of a button on the dash :-)

W/O a tune the DME will "adapt" to them, but the flow increase will only be noticed for the most part at very High RPM's under higher boost conditions.

I also don't think its worth spending close to $2K on HFC's unless you run the 200 CEL ones and a tune. I have the Wagner Euro HFC's and they are great.

I've got Dry air filters, a AA midpipe and OEM axle back on my car with a Stg 2 BM3 tune. Its fairly quiet in comfort mode, but is about 50% louder with the flaps open and running in Sport or Sport Plus.

Hope this helps....
HAZMAT

[Megator]

Originally Posted by SEAT TIME RULES

I've run performance 100, or 200 CEL HFC's on a EVO X and now on my M2C.

You will throw a code with any HFC below 300 CEL IMHO.

You can clear the P0420 code just before taking it in for a sniffer test and as long as the code doesn't pop back up you should be fine w/o a tune. I ran the new cats w/o a tune for about 2 months. I could go about 75-100 miles before it would throw the code again. I have a AK Motion Display that allowed me to clear the code with just one touch of a button on the dash :-)

W/O a tune the DME will "adapt" to them, but the flow increase will only be noticed for the most part at very High RPM's under higher boost conditions.

I also don't think its worth spending close to $2K on HFC's unless you run the 200 CEL ones and a tune. I have the Wagner Euro HFC's and they are great.

I've got Dry air filters, a AA midpipe and OEM axle back on my car with a Stg 2 BM3 tune. Its fairly quiet in comfort mode, but is about 50% louder with the flaps open and running in Sport or Sport Plus.

Hope this helps....
HAZMAT

I wish you were on this side of the pond, doing track days together and talking cars seems like it would be a hoot.

[MR RIZK]

https://www.bimmerpost.com/forums/sh...php?p=26469543

[mike@x-ph.com]

It won't add much power on a stock map

[SEAT TIME RULES]

Originally Posted by MR RIZK

https://www.bimmerpost.com/forums/sh...php?p=26469543

Interesting comments...

On my car the following occured:

AA Midpipe went on first. Overall volume up 20-25% over stock.

Wagner 200 CEL DP's then went on a few months later and they really opened up overall sound levels. Another 25% IMHO.

So a total of 40-50% with the flaps open...

[blitzyo]

Thanks for the comments and the link to that thread Mr. Rizk. I'll hold off my downpipe purchase for when I get a tune after my warranty expires.