Quote:
Originally Posted by Can'tHave2MuchHP
Not to be a negative Nelly but there's no way deleting the ~8" of crushed pipe by the axle of this car is going to do anything sound or HP wise, unless you're pushing big power, then everything starts to come into play. If you scrapped the secondary cats THEN you would notice a different. I don't see why you'd cut up the stock cat-back just to delete that, shoulda just went with a Borla 60606 or 60607 at that point. That would delete the crushed, and delete the secondary's if you want (60606 does, 60607 doesn't).
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I respectfully disagree with you on this topic. I didn't do it for the sound. I don't/didn't want to delete the 2nd cat/resonator whatever you want to call it. I just wanted rid of the crushed down section. I used to design exhaust systems, and this crushed section may not make a difference on a SS , 455 hp car, but at some point it becomes a restriction to flow. To my knowledge no one has dyno tested it's replacement on the 650 hp LT4 cars. The crushed part has about as much fliw area as a 140 hp Honda Accord 1 3/4" exhaust. If you search back through threads on Procharged cars, there has been whp increases on the LS3 by switching to 3" catbacks. So it's been proven that you can get power by decreasing backpressure IF your air flow is high enough. In my opinion the LT4 meets this criteria.There have been people that came up with engineered reasons for the crush pipe section. Such as to stop drone, to make an exhaust crumple zone, etc. From what I've seen, the only reason you ever crush a pipe is to create more clearance around something. I have read that a convertible owner claimed there was a brace on the convertible that this crush piece was meant for. GM choose to consolidate exhaust systems on all dual exhaust models, Convertible, Coupe, SS, ZL1. In my opinion that is why the crushed section is there. I don't think it was done on purpose for the coupe, it's just an unfortunate part of the consolidation.