Originally Posted by swamp2
OK short(ish) and sweet, no dyno testing. Nothing really novel to share - this is pretty much along the lines of what prior posters have stated.
I got a set from Turner (in their latest group buy). Unfortunately they came with bad threads on the sensor bungs. They promptly replaced the bad set with a new one but would not advance ship the replacements and had to charge me for the 2nd set, to be refunded upon return shipment of the first set. New ones looked a lot better but still not quite "grade A" machining. Sensors mounted fine though.
I decided to have the system welded together rather than clamped. I have an entire OEM midsection for when I am not using the car on the track and for any potential inspection issues.
I used a nice exhaust shop up in Oceanside, CA who more or less did the install while I waited and charged a very fair and even low price. I can provide the shop name by PM. The guys also caught a small repairable leak from me slightly botching my cat back install and fixed that for free!
The power from this mod is clearly noticeable from a butt dyno. I ain't bothering with a "real" dyno. Most folks, including Turner, are claiming from dyno work about 30 hp and I believe that figure. It is about a 7% decrease in weight/hp ratio. I firmly believe you can't really feel a couple percent (and there certainly many posts here stating "I have" or you can...) but this for sure you can feel. The traction control hits sooner and more often for sure. That might be the most significant change I've noticed.
Definitely different and an improvement. Shifts sound quite different. I hear more engine and exhaust "activity" during the shifts themselves. They sound a bit more gradual "slur" between them and they sound even slower than before the mod (of course I know they are not actually slower). Not a bad thing just an observation. Not a tremendous difference in loudness or sound quality at low to mid rpm. Yes you notice you've modded the exhaust but neither significant nor annoying. There is also a very very small bit of added drone at some rpms. A small downside IMHO. However, when you open her up the result is great - significantly louder. I have the Vorsteiner catback as well and I would not call the sound quality significantly altered but it is certainly changed. Without spectral measurements this quality change is tough for me to describe. I would describe the change as about the same as the catback itself but probably even a bit more at high rpm+load.
A very very slightly noticeable change with some more smell. Only noticeable at start up and say when backing into your own plume. Perhaps its the colder weather, or perhaps the effect is real, but I think I see more visible exhaust when the car is warming up. But because I know that is almost all CO2 and water vapor, I kind of think this one might be more the weather than any real effect.
Obviously this mod is not CA smog legal and will make a bit more pollution especially during warm up. I know most wont care. I obviously care enough to simply mention it. Maybe that's even more hypocritical... No such thing as a free lunch on this point.
Overall I rate this mod very highly and it is very likely the single biggest gain per dollar mod you can do for this car. I can't wait to combine this with pulleys, a BPM tune and some race gas! I think that is all that is required to get to the 400 whp mark.
By the way 100 octane race gas is available at Crown Point Gas on Ingraham south of Pacific Beach here in San Diego. That too is fun stuff.
Run some race gas through it..the smell is glorious...
I run 4 gallons of 100 VP racing every tank full. Just found a source for Sunoco 104 in 5 gallon jugs.
2013 M3 Coupe-MR/BLK ZCP, ACM test pipes, BPM Stg2 dev. tune and Megan catback, AFE Stg2. with C/F elbow
Previous rides: 2011 M3 Coupe-MR/Blk
2007 Porsche 997C2S Speed Yellow/Blk sport seats
2004 BMW M3 Imola/Blk