I am still under warranty so I don't want to do downpipes yet because they throw a CEL and my dealer will not warranty it if the exhaust causes it. The dealer did say that any air in or air out mod that dosen't throw a CEL. So looking at the catback systems that people seem to have here Corsa is by far the most popular. To me the Corsa is too raspy. I think the best sounding exhaust on the videos I have seen is Borla but people complain about drone on it. I like how the Borla is still quiet at low RPM so you can still conserve the sleeper a bit but you can actually get the car to make noise if you want to.

I also think you need to hear exhaust in person to know what it is going to sound like. Am I correct in believing that the youtube videos don't do any exhaust system justice?

U could go the catted route for downpipes. Was told they dont throw codes. Just got me them and waiting to install

Quote from: sunwolf on April 14, 2015, 04:46:19 PM
I am still under warranty so I don't want to do downpipes yet because they throw a CEL and my dealer will not warranty it if the exhaust causes it. The dealer did say that any air in or air out mod that dosen't throw a CEL. So looking at the catback systems that people seem to have here Corsa is by far the most popular. To me the Corsa is too raspy. I think the best sounding exhaust on the videos I have seen is Borla but people complain about drone on it. I like how the Borla is still quiet at low RPM so you can still conserve the sleeper a bit but you can actually get the car to make noise if you want to.

I also think you need to hear exhaust in person to know what it is going to sound like. Am I correct in believing that the youtube videos don't do any exhaust system justice?

I also believe that computer sound systems prevent much analysis of exhaust sound. All sound different on my phone, laptops, and desktops with the same video.

Consider catted DPs... Dyno comparison BTB catted vs non-catted shows maybe 10 WHP less on my car than uncatted, my dealer likes them, no CEL or turning O2 sensors off, and the turbos still spool much earlier even with stock exhaust making much low end power.  Look at the stock DPs... Much restriction there, why put that in front of a nice fatback to make it work less efficiently?

From the research I have done I wanted to go with Livernois downpipes when my warranty is up. I got mixed answers from LME about the CEL with their downpipes but they claimed they are the biggest allowing the most flow. I fully intend to have downpipes on this car as soon as i hit the 36,000 miles as that will be way before my 3 years. Correct me if I am wrong about the downpipes but I haven't looked in awhile and I don't remember any good comparisons between downpipe manufacturers.

Catless downpipes can be done without throwing cel's and it has nothing to do with turning off the rear o2's..it's more complex than that.

And the down pipes don't have much to do with how fast these turbos can spool...these are baby turbos and are meant to spool at 1500 rpms on their own....in stock form with stock pipes you can easily run 20 psi by 1800 rpm it's all in the tune...you can argue that these turbos are undersized so spool is never an issue

Quote from: ajpturbo on April 14, 2015, 05:34:02 PM
Catless downpipes can be done without throwing cel's and it has nothing to do with turning off the rear o2's..it's more complex than that.

And the down pipes don't have much to do with how fast these turbos can spool...these are baby turbos and are meant to spool at 1500 rpms on their own....in stock form with stock pipes you can easily run 20 psi by 1800 rpm it's all in the tune...you can argue that these turbos are undersized so spool is never an issue

To be clear I want to take it to the dealer on the stock tune without a CEL.

Quote from: ajpturbo on April 14, 2015, 05:34:02 PM
Catless downpipes can be done without throwing cel's and it has nothing to do with turning off the rear o2's..it's more complex than that.

And the down pipes don't have much to do with how fast these turbos can spool...these are baby turbos and are meant to spool at 1500 rpms on their own....in stock form with stock pipes you can easily run 20 psi by 1800 rpm it's all in the tune...you can argue that these turbos are undersized so spool is never an issue

q
Granted possibly not spooling earlier... But the Dyno graphs with 3 different sets of DPs shifted down from a power spike starting about 2000-2100rpm to 1500-1600 rpm on my car with stock tune... Regardless of the reason useable TQ and WHP start sooner.

If you live in an emissions state you need cats with a carb number to pass visual inspection... I know that the car can be adjusted to not throw a CEL with non-catted DPs (catted PPE don't anyway)... But have you been able to adjust the car so that the emissions are all reported as functioning normally via OBDII port?... In AZ they plug in as a "readiness" test and fail the car if there's any question of emissions malfunction... States vary of course.

Yes all of the i/m monitors can be set to ready...I would agree that with stock settings down pipes are beneficial but it could be better even with no down pipes..bigmac I believe u totally that the power curve shifted for the better