DD515

This is my 1st post on Corvette Forum, so please bear with me.

I had a 2013 Grand Sport Coupe / manual with the Mild To Wild exhaust option. I removed the fuse and the car had nice rumble at idle, a very aggressive sound through acceleration and downshifting produced a significant amount of "backtalk" through the exhausts.

Today, I have a 2017 Grand Sport Coupe / manual with NPP. My suspension is set to Sport and the exhaust is set to Track however; the fuse is removed.

Sadly, the exhaust tone is nowhere near that of the '13 at idle or during acceleration, and there is virtually no "backtalk" during downshifting.

I have looked at after market exhausts but am inclined to simply remove the mufflers and NPP valves and just run pipes from the cats, back.

I would appreciate any suggestions on that mod or how to get both up and down shift sounds to be more aggressive?

Thanks

Thanks

poughkeepsie

I did this exact thing today. Took it to an exhaust shop and had him sawzall the pipes right at the mufflers. He then bent a 3" pipe for each side into the corsa tips I bought. I also installed a corsa x pipe a week ago. Now the car sounds like it should. I'm going to weld a piece to the muffler so I can slip them back on if needed. Total cost was $200 in labor plus the $350 for the corsa tips. Well worth it for the way it sounds now.

DD515

WOW! Were you taking off the NPP system and did /do you have to make any adjustments to other sensors or the computer?

If you don't mind, plz email me at corvettesanonymous@gmail.com

Thanks

Dcasole

How did you stop the car from throwing a code …. did you somehow keep the AFM valves plugged in …….???


OP , most go with the Borla X pipe which removes the second set of cats , its a 1 hour bolt in swap , I can assure you that if you install the X pipe and turn off AFM, the C7 is just as loud as the C6 and will burble on downshift just like the C6 , the one thing it does not do, that the C6 was terrible with, is DRONE at high speeds when the mufflers are open

A C7 just does not sound loud from the drivers seat because of the active noise reduction that the C7 has using the cars sound system

Have someone else drive your car while you stand out side and listen to it as it goes by you , you will see what mean , its not as quiet as you think it is ….

When I first got mine , my kids would say " we heard you turning into the subdivision …. " to me I did not hear a thing ….

( I had a C6 with headers X pipe and NPP so I know the sound you are looking for , its there , you just can hear it from the driver seat )

Dave

rb185afm

DD515

Thank you to everyone who responded. I spent about 40 minutes on the phone with a Borla Tech and ended with the belief that I just "can't get there from here" without a whole new system - minus headers. He recommended X-pipe + ATAK-S with a cost +/- $2500 + installation which is another +/- $500. That said, I'd now be looking at a +/-$3000 system + the $1500 for the stock w NPP that I would be discarding. Ergonomically, that makes no sense to me.

I've investigated cut-outs and find a real mixed bag. At this point, I'm seriously thinking of going the 'muffler delete' route and very much appreciate the above video. Further up poughkeepsie stated he had done that at a very reasonable cost ~ although the X-pipe may still be in the equation.

I also appreciate the comments on the C7 sound deadening feature. UGH! Wonder if Ferrari has that?

I had a '70 Coupe with unmuffled side pipes that exited just behind the doors. My thinking is that this GS with muffler delete should sound really good, be Louder inside, but still not as loud in side as the 70 was.

Thanks again!

rb185afm

Bill Dearborn

Removing the fuse basically leaves you in track mode all the time. On M7 cars with the exhaust set in Track Mode the only time the exhaust valves close is when the the engine switches to V4 operation in Eco Mode. If you don't drive in Eco Mode then you really don't need to pull the fuse.

Bill

DD515

Thanks Bill. I'm not 100% sure, but it is my understanding that the GS does not have the V4 operation ~ at least my M7 does not.

Zjoe6

It most certainly does.

ahero4eternity

cerino2000