2014 SHO PP. At 1200mi car was fine no smoke and no mods. Installed my SW catless DP's and SW cat back. I noticed when I revved the car in the driveway excessive smoke and during decels after an aggressive pull. It was driving me nuts and hurting my brain. It was immediately after installing my exhaust. I refused to believe it.
I didn't want to go through the trouble of taking off the DP's so I just put the stock cat back on and left the DP's(catless). Smoke is virtually gone, when I rev the car and let it hit of the 4200 neutral rev limiter and check the exhaust I can only see a small trace of smoke.
I guess the 3rd cat of the stock cat back cleans it up a bit. I highly doubted that the turbos were bad since the car was brand new and only had 1200mi and it wasn't smoking before the catless DP install and re installing the stock cat back with the 3rd cat and making the smoke all but disappear proved that the turbos were ok. I really wasn't crazy about the sound of the exhaust anyway, I think the engine sounds kind of goofy so I like just the catless DP's as they make it just a bit louder but same kind of note.
Mine smoked the worst when I revved it and held it at the neutral rev limiter and quickly checked the tail pipes. I was thinking maybe since the car is direct injection and the fuel is sprayed very late and maybe something to do with how the spark and rev limiter act maybe there is more unburned fuel I have no idea.
But I do know that putting the stock cat back with the 3rd cat back on made the smoke go away. It was night and day.
Maybe the cats mask a problem. But I doubt the seals in my new car's turbos were bad, they were not overboosted from stock at that point.
I wouldn't think the seals are cheap as some have said, they are garett turbos right? And I could be wrong but I don't think they are like rubber seals that can blow out. I thought they were like precision's turbo seals which are a dynamic ring seal meaning they are metal rings that expand with heat but I'm just speculating there.
So some here will say that my turbos which still have less than 3k are bad and my 3rd cat is cleaning the exhaust and concealing the problem. I can't argue that but I wouldn't buy that logic. So if that is your contention, then you are also saying that my turbos were bad from day 1. I won't subscribe to that but I've been wrong before. Hope this is good insight for you all
