get a test pipe or not?

[Jon2000]

Hey guys,

I have a 2007 MS3 with Cobb SRI, Cobb TIH, Cobb AP (v200 stage 1 sri+tih map) and will be installing my Mazdaspeed catback exhaust. Just wondering if you recommend switching out the 2nd cat for a test pipe while I'm at it. Has anyone had any issues with emissions while only having 1 cat?

I'm not doing the downpipe + stage 2 tune yet as I'm sure I would need a HPFP.

Thanks in advance,
Jon

[loki]

I would just wait till you're ready to install downpipe and then buy a dp that replaces both cats.

Unless you're planning on going with a 2 part system like Ultimate Racing.

You won't have to do emissions testing for a while if that's what you're asking (7 years from age of newer cars), but obviously if you remove one of the cats your emissions will get worse and the car will smell different.

[Unoriginalusername]

CTA Patrick's dyne results with the vibrant system were very close to those who did the dp. this method is less expensive, less noisy and almost the same gain and doesn't seem to cause and smoking turbo issues. I don't think you need a different fuel pump with those mods

I really liked my CPE TBE but if I had to do it again not sure it's worth the money (incl install) when other options yield similar gains

[Fobio]

regardless of which route you choose, you will be wise to now also choose to monitor fuel pressure regularly. It is not necessarily a case of a downpipe and a Stage 2+ tune requiring a HPFP...it becomes a case of the weakest link rearing its head.

when you improve the efficiency of the exhaust system, an integral part of the overall turbo engine, thereby allowing the turbo to work a tad harder to make more boost, and thus more power, it will invariably begin to tax the other parts and systems that it works with...including the fueling, to either achieve a certain load or boost.

[Jon2000]

Thanks for the opinions and time guys. I installed the CBE this afternoon since it was a nice day. Very impressed with the outcome so far. I will monitor things more closely now with the AP and post up some logs soon.

Please feel free to continue the discussion.