I bought my GS Centennial not long, and promised I wouldn't go too crazy on modding for a while!

So far I've done a few things - M2W, Window Valet, MGW Shifter, CF Accents, Hardwired Escort Radar... My plan was to wait for a while until I did exhaust, and the idea was to do LTHeaders, X pipe, and Varaham (spelling) Intake.

However, I just stumbled upon a good deal on a set of LG 1 3/4" Headers, 3" LG catted x pipe - 3" - 2.5" reducer to NPP.
I already have the NPP so I would sell that one for, I don't know about 300 is that they seem to be going.

Question is, would I have to 100% get a tune for it? (Due to 02 sensor issues. It include 02 sensor extensions ). Sometimes you can just get the code flashed... but I don't want to be running lean/rich or anyting like that... my commute to work is 50 miles/day!

Would it destroy my factory warranty?... and even so would they be able to blame that on many of the things that can go bad, since they can only blame aftermarket things that directly affect the parts that go bad?

What are your overall opinions on going from stock LS3 NPP setup to this?

Thanks!

Pic of my C6 as a thank you for adding your input!

 

Sorry I can't help you with your question but I'm planning on this very project later this year. I'm interested in hearing the outcome as well.

 

I just did the Kooks LT 1-7/8 headers and catted X-pipe into the NPP exhaust and love it.

A tune will be necessary.

I gained about 30 HP and TQ with my setup and tune

 

Yes you should get a tune

Would it destroy your factory warranty? No with some exceptions.

If you bring your car in for an issue related to intake and exhaust, well you are on your own. But for something unrelated, like headlights or your power seats not working, those will still be covered under your factory warranty.

My 2005 had intake, kooks LT, x-pipe, magnaflows, cam, tune…Never had an issue with taking it in for warranty repairs.

With long tubes + NPP, it will get a decent amount louder when in "wild" but that's the beauty of NPP. Too loud? Just go to mild.

 

Thanks Homer3D.

How would you compare the Wild Mode OEM Manifold+NPP to the Mild Mode LTHeaders+NPP?

 

Well I don't have long tubes on my 2013 GS which has NPP. On my 2005, here were the mods in the order they were installed

Magnaflow mufflers - Nice mellow tone over stock. Not loud
Headers + X-pipe - Got much louder, drone around 65-70mph but livable
Cam (228/232) - Got even louder, drone made it hard to have a normal conversation on the freeway.
Swapped back to stock mufflers - Super quiet, couldn't even tell it had a cam.

Personally I am trying to stay "smog legal" here in California as it was a challenge to get my 2005 to pass smog. However, if it wasn't for that issue I would have no hesitation with putting on some headers. The power gains plus the more aggressive exhaust tone is a win win in my book.

 

^Agreed.

I hope someone can chime in about the tone/drone with the NPP + 1 3/4 headers combo. I would have to get drone at cruising speeds, as the Vette is my daily and I deal with interstate speeds for 30mins in the morning and 40 mins at night!
Im annoyed at having to tune as well! I would really like to be able to tune after doing the CAI and maybe ported heads or a mild cam, but I guess the o2 sensors have to be deleted from the system! having a tune is what im worried about with warranty, as the dealer can blame a lottt of stuff on that!

 

I have NPP mufflers as well and I'm going with headers any day now. I'm a little stuck because when I order my headers and X pipe, I have to decide right then if I'm going with 2.5" end which will fit my NPP or 3" which would fit a BB Fusion exhaust.

 

You will not get any drone with the NPP in "quiet" mode, and it will roar a lot louder when open

If you get a reputable tuner to set you up, you will be glad you got the tune. They leave the front O2 sensors working, and that is all that any car needs to run properly.

I went with the 1 7/8" LG Super Pros, and love them. With my tune, I gained about 50 rwhp and about 50 rwtq.

This thread has a dyno graph of mine and others, after a tune. https://www.corvetteforum.com/forums...-question.html

 

I did the CAI and headers with a Tune at the same time to save $ on tuning. I have 1 3/4 long tubes, catted x pipe, NPP exhaust, RamAir SS CAI. Had some issues with NPP in a box so had to run the car for a few weeks without "mild" mode. Some drone around 1500 to 2k rpm. It is livable though and I love the sound when in "wild" mode. Had some vibration issues with long tube install which took more time and a second visit to install shop. Passenger side is very tight with some long tube headers. The pipe from the passenger side front manifold port should sweep in front of other pipes not behind. There was some touching of x-pipe to heat shield bolt by diff/trans in the rear. Very close to bell housing heat shield in the front pass side. Shop unplugged back O2 sensors but forgot to remove in the tune so codes were thrown. Had them install rear O2 sensors with extensions in case of warranty issues.

As with any work done on our cars recheck all work performed by others as they could care less about our cars. My original install was so sloppy, bolts pointing different ways, missing o2 sensors, rubbing of pipes making a hell of a clanging noise. Totally different than the sit down with shop owner and assured of professional install and his vast Vette experience. I understand general shop working environments, owner busy selling, shop lackys installing and not caring. Don't be surprised if you have to go back to get it exactly right.

 

I have an 08 with LG 1 3/4" headers, high flow cats, and NPP. I am getting no check engine lights. I do have a tune, but just the canned tune included with the DiabloSport InTune. And that tune was in place before the headers were installed.

With the exhaust closed you can't tell that headers are installed. With them open you might get a little drone at certain RPMs. But that is just music to my ears :-)

The sound improvement at wide open throttle is friggin' awesome!
It'll definitely attract a little more attention......

 

^ ooooo you guys are killing me!

I was so dead set on not messing the car until way later in the year.... man this mod bug has to leave me. It's been non stop since 16 just leave me/my wallet alone!

I might have to get it done then!
What do you guys think is an amazing deal on used lg headers/catted x pipe /3 to 2.5 piping and np exhaust system?
How much do you guys think I can get out of an excellent condition npp system with 20k miles?

Thanks so much!

 

Why do you want to sell your NPP? I paid $600 gladly for used NPP mufflers that came off a 2011 GS (seen them used for as high as $800). The headers and x-pipe fit fine into GS NPP mufflers that are 2.5 inch. If you are buying a "whole" system used from headers all the way back, ask why they are selling, they may need yours to put theirs back to stock. Could be real cheap in that case. More info is needed.

 

I have a very similar setup.......1 3/4" with 2.5" off-road X and NPP's........running open 24/7 and it does NOT drone at all.

Here's an idle sound bite:

http://vid1097.photobucket.com/album...pst0zkjxfg.mp4

.............your 3" X-pipe will have a slightly deeper tone.

 

^ thanks ill def check it out. I can't right now bc I don't want to blast LTheaders at work lol

^^ I want to sell my NPP or the NPP that comes since I already have it in my car so I'll have an extra set. The rest (from muffler up) I don't think I'll sell as I want to keep a full stock set in case I need to revert back from headers/x pipe

 

Now know what my car would sound and look like with headers.

Are you running an aftermarket cam as well?

 

That car definitely has a cam in it. What beautiful music

 

Comp Cams LSR 54-454-11 [227/243 .614/.624 113+2]..........with LG 1 3/4's into off-road X and factory NPP's running open at all times....(no fuse).

Nothing better than a big cam N/A setup.

 

I have a 13 Grand Sport with cold air intake, American Racing 1 3/4 long tube headers, high flow cats, x-pipe into NPP w/M2W switch. I like loud exhaust but the drone at low RPM is miserable. Once out on the road, it is better but the drone can be a real PITA. I guess I have become used to it but I am still looking for a different set of mufflers. The headers really changed the sound for sure, and the performance, but drone will be a real issue and probably leave you searching for a different set-up in the end. The drone I mention is with the exhaust in the loud mode. No drone in the quiet mode so you can control it if you choose but then the car is so quiet it doesn't seem like all the work was worth it. Currently looking at Billy Boat Fusions or Corsa products. Billy Boat may not be the answer for drone but Corsa seems to be all about drone free with a good tone.

A tune was necessary for my car. Good luck with your decision.

 

Has anyone experienced drone using stock Z06 NPP mufflers to maintain 3" all the way out?