Sean Michael
Member
Studying pictures online it appears the GM performance exhaust by Borla has a resonator before the muffler and no spring-loaded valve, while the GMPP Performance Exhaust (84888291) doesn't have the pre-muffler resonater but has the valve. I'm referring to the spring-loaded valve that's intended to help with DFM drone, we've established these trucks never got an active exhaust valve. This was just observed from looking at pictures, I've never set eyes on either in person.
I was leaning towards the GMPP version because GM actually qoutes an 11hp increase but they don't say the same for the GM by Borla version. Also, I'm assuming the RST Performance Edition uses the GMPP version from stock, and that truck is officially listed at 433hp, with GM stating most of that is via the exhaust upgrade. Makes sense, most people acknowledge that a CAI provides limited to no actual power bump, especially without a subsequent tune, and the RST Perf Edition only gets exhaust and CAI for its power bump as far as I know. I feel more confident the GMPP actually provides a bump in power, being that OEM car manufacturers tend to be conservative about officially listed power numbers. If that ~11hp bump is even noticeable in actual real world use is a whole other conversation.
I'm really torn, the GMPP is around $3,300 whereas a catback directly from Corsa or Borla is quite a bit less expensive. Also, the aftermarket cat backs don't have the valve, and I really want to avoid DFM drone, I read that it sounds like a helicopter when cruising and DFM activates. Guess I could play around with that mod people do to hold the stock valve open to see what it sounds like, that only costs a couple of hose clamps and a few minutes under the truck.
Someone help steer me right on this, I want catback exhaust, I would rather err on the side of a mild volume increase as opposed to being obnoxiously loud, and I absolutely want to avoid drone, which is a hard line for me - zero drone required. This truck is mainly driven by me, but I do take my family on road trips. I also would feel more justified spending the money for a HP gain, even if it's modest, and even if it's not necessarily percentable I would feel like it was more justifiable. If I just wanted more sound, I could have a muffler shop switch out the muffler alone for just a few hundred dollars compared to several thousand for a catback.
I was leaning towards the GMPP version because GM actually qoutes an 11hp increase but they don't say the same for the GM by Borla version. Also, I'm assuming the RST Performance Edition uses the GMPP version from stock, and that truck is officially listed at 433hp, with GM stating most of that is via the exhaust upgrade. Makes sense, most people acknowledge that a CAI provides limited to no actual power bump, especially without a subsequent tune, and the RST Perf Edition only gets exhaust and CAI for its power bump as far as I know. I feel more confident the GMPP actually provides a bump in power, being that OEM car manufacturers tend to be conservative about officially listed power numbers. If that ~11hp bump is even noticeable in actual real world use is a whole other conversation.
I'm really torn, the GMPP is around $3,300 whereas a catback directly from Corsa or Borla is quite a bit less expensive. Also, the aftermarket cat backs don't have the valve, and I really want to avoid DFM drone, I read that it sounds like a helicopter when cruising and DFM activates. Guess I could play around with that mod people do to hold the stock valve open to see what it sounds like, that only costs a couple of hose clamps and a few minutes under the truck.
Someone help steer me right on this, I want catback exhaust, I would rather err on the side of a mild volume increase as opposed to being obnoxiously loud, and I absolutely want to avoid drone, which is a hard line for me - zero drone required. This truck is mainly driven by me, but I do take my family on road trips. I also would feel more justified spending the money for a HP gain, even if it's modest, and even if it's not necessarily percentable I would feel like it was more justifiable. If I just wanted more sound, I could have a muffler shop switch out the muffler alone for just a few hundred dollars compared to several thousand for a catback.
