SASprof

I've had my M7 C7 for a whopping 19 days and 450 miles on local city streets. (I won't take it on the freeway, where varying the RPMs outside a narrow band is difficult, during the breakin period.) Aftermarket exhaust installed 3 days ago. First impressions.

The base exhaust is an absolute wimp, an embarrassment on such a hot looking car. NPP is a popular and well-priced option which looks and sounds far better than the stock exhaust (a very low bar).

I passed on the NPP because I did not want my exhaust tangled up with the C7's electronics. NPP owners are quick to point out the menu item which sets the butterfly valves to always open. However, the driver does not have the last word. The computer does. Typical Chevy. Many NPP owners have posted that, even set to always open, the NPP exhaust quiets down on its own when it wants to. Some NPP owners have tried pulling fuses, with mixed results. My foolproof solution: Order the base exhaust, trash it, and replace it with aftermarket. The C7's computer is now out of the exhaust business. Permanently.

Southern Car Parts shipped my B&B PRTs directly to my local Chevy dealer, which installed them for $250. Extra time and muscle, and a call to B&B, were required, but the PRTs eventually went on, lining up perfectly, with no codes thrown (so far, anyway). Now, instead of a computer controlling my exhaust note, I control it with my right foot.

When I first got my C7 19 days ago, I enjoyed Pandora so much I bought a subscription for $5 per month. After installing my PRTs ... bye bye Pandora. Instead, I listen to the sweet music of my LT1, which sings to me and tells me when to shift. My smoking hot car now has a sound to match its looks. The shiny round 4" exhaust tips look great (as do the NPP exhaust tips).

For those concerned about drone, B&B advertises the PRTs (Purge Resonance Technology) as drone-free. (I can't personally verify that, as I have not driven my C7 on the freeway yet, and won't while it's in the breakin period.) If drone doesn't bother you, and you want maximum aggressive, go with B&B's Bullets. The PRTs, however, sound plenty aggressive to me. Delicious bark on start-up, deep low throaty rumble at idle, aggressive when you stand on it. Controlled by the driver. Not the computer.

richysvette

I love my prts and no drone on the highway. Awesome system!

drewauby5

sound clip??

thrilled

I'm leaning towards B&B Bullets.The location corvette shop says they'll do the labor for $300.
Did you shop around and get A good price on the muffler?

SASprof

Southern Car Parts: $1450. Same for Bullets. Free shipping. No tax for Cali residents. They often have discount coupons on their site, or if you previously ordered from them.

drewauby5

SAS...any sound clips of exhaust?? Extremely interested

SASprof

Sorry. No sound clip yet. Possibly later.
Check B&B website? Or Youtube?

drewauby5

OK thank you

SASprof

Wonderful post-breakin 250 mile road trip along the coast yesterday. 750 miles total on my 3.5-week-old C7. CEL this morning. Maybe related to PRTs, as some have reported. Maybe not. Goes to dealer tomorrow. Will know more then. Will post.

yell03

Any info on the CEL?

SASprof

Dealer confirmed CEL related to aftermarket exhaust valves. Dealer wanted my Vette overnight. I said no, picked up my Vette, CEL cleared on it's own, stayed off for several weeks, then came back on. Seems related to Eco mode (4 cylinders). Going back to dealer Tuesday. Otherwise, I luv my B&B PRTs. Looks and sounds great. No drone. No entanglement with car's computer.

Jack Be Quick Racing

If all you've done is mufflers, seems odd to have the CEL come on. If it's related to 4cyl mode I am wondering if the reduced back pressure is some how making the computer think the eco mode valves are not functioning correctly. Or, is it just not connecting correctly with the valves from the BBs?

Either way, dang. I hate to think you have to run a tune for mufflers alone. I thought BMWs were picky.

Mdm23

What's the big deal with NPP the exhaust being involved with the car's computer? The NPP works great IMO. Not knocking anyone going aftermarket but I don't know why the OP is so concerned by the "entanglement" with the PCM.

SASprof

Yes, I think you nailed the possibilities. I'll know more next week.

SASprof

First, I want to say I'm no big expert. Second, I don't have NPPs, so I can't speak from experience. All I know is what I read on this forum, which is that many folks love their NPPs. No question they're way better than stock. The other thing I read in numerous threads is that, even with Sound Management OFF, the NPP valves close on their own, when the computer tells them to close, leading many folks to pull a fuse to prevent this behavior. That is why I wanted to avoid "entanglement" with the PCM and why I went aftermarket. I just want good sound all the time.

yell03

Please keep me posted, this is the system I want, but not if it thows a CEL

kp

You still have two computer controlled AFM exhaust valves in the picture without NPP, seems the B&B valves are the problem according to others with issues. most likely if you never use ECO mode (manual trans) or always drive your auto in manual mode the CEL wont come on.

Corsa has you cut the pipes and retain the factory over axle pipes and AFM valves, great idea but adds more clamps that can loosen an leak and a little extra labor, plus trashing your stock exhaust.

I liked the PRTs on my C6s, but I'm waiting until B&B gets the AFM valve thing straightened out before I try for myself. If these were like the C5/C6 that took 10 minutes to swap exhausts I would try it, but having to yank off the plastic rear valance is a bit of a PITA to do exhaust roulette with. No doubt the stock non-NPP exhaust is a little too quiet but at least it doesnt attract much attention..

Vetteman Jack

Sounds like you found an exhaust system that will make your driving the car a real treat.

SASprof

Picked up from dealer today. Dealer contacted Chevy. Said they needed to "calibrate" the valves. Cleared code. Test drove in Eco mode. No further code. I'll give it a good 200-mile run this weekend to be sure the code doesn't return.

yell03

Keep me posted....

Chevy had no problem with the aftermarket exhaust and warranty?