I have a 2012 grand sport with arh zr1 headers. I need to know which axle back to go with to have 3" all the way through. I know there were changes in 2009 and again I believe in 2011. I need to know the date range of exhausts I should be looking at and for which type of c6. For instance, do I need exhaust for 09-? Zr1? Exhaust for 09-? Z06? I'm very confused on this

 

I would say give the manufactures of the different systems your considering a call.

 

I believe the ZR1 is the only model with full 3" exhaust.

Z06 is 3" into the inlet of the mufflers, then goes down to 2-1/2" inside the mufflers.

ZR1 is 3" through the mufflers.

Someone else will need to confirm this.

 

The 2009 change to the passenger side over axle pipe only affected the LS3 cars 2 1/2" exhaust. The Z06 3" didn't have the same change.

So you just need to get the proper ARH 3" x-pipe to match your headers, basically a Z06 system. Keep in mind that the 2012's introduced the 2nd set of CATS so you will have to specify if going catless, or with one or two sets of cats (hopefully only one ).

 

I have their cat less x. My only concern is axle back

 

This is not correct. The ZR1 mufflers also neck down.

OP....
2011-2013 Z06 and ZR1 mufflers are identical. Both are 3" and have the same internal construction as the '08 and up NPP mufflers. People like these mufflers due to the sound.

'09-'10 ZR1 mufflers are 3" like the above

'06-'10 Z06 mufflers are 3" like the above but the internal construction is different. The "straight through" side of the muffler used a perforated pipe that makes them a little quieter and have a slightly different tone. People often do the "muffler mod" on these so they sound like the later mufflers. Tons of threads and pics regarding this mod.

Bottom line is you can use any of the above, all will bolt right in and all share the same external size and geometry.

 

From what I have read, there was a design change in the over the axle pipe in 2009. Also, in 2012 there was some sort of x pipe change due to the introduction of a 2nd set of cats. If you look at Akrapovic exhaust it mentions something of this and requiring to buy their x pipe to allow fitment.
I have a 3" borla touring that I believe came off of a 2008 z06. It's doesn't even come close to fitting.

 

The change in 2009 was for the 2.5" base exhaust system only. There was no change to either Z system regarding the over axle pipe. You can take 2006-2008 Z06 mufflers and bolt them on any year Z06 or ZR1.

The change to the 2012 x-pipe has nothing to do with the mufflers. Any year OEM Z muffler will bolt to any year OEM Z intermediate pipe. The difference is attaching the intermediate pipe to the primary cats. You cannot bolt a 2012/13 Z intermediate pipe to 2011 and earlier Z primary cats (and vice versa).

Your issue is likely with the intermediate pipe you are using.

 

Are u saying there was no change in over the axle for my grand sport?

 

<sigh>

The Grand Sport uses the base 2.5" exhaust system. Therefore, the over-axle pipe geometry is the same as the over-axle geometry as the 2009 & up base system and it differs from the 2008 and earlier base geometry.

You stated in your original post that you are using a 3" system. The 3" systems ONLY came on the Z06 and ZR1. Therefore any changes to the base/Grand Sport system are a totally mute point. There was NO change in over-axle geometry for the 2006-2013 Z cars.

You need to identify exactly what parts you are using. I'm beginning to think you have a mix of base and Z parts which is a hack job at best.

 

No you are just not reading carefully enough. As stated in the original post, I HAVE A 2012 grand sport. I am using zr1 headers. I want a 3" system all the way back. So if the geometry is different on base and grand sports I'm curious to know if z06 and zr1 exhausts will fit. I currently have a 3" borla touring that comes nowhere close to fitting.
To assume my car is a "hack job at best" actually pi**es me the f*ck off as I have spent over 25k in modifications to the car. I clearly purchased the wrong axle back and I'm trying to determine exactly what exhaust I should be looking at that will accommodate 3" all the way back to mate up with zr1 arh headers and fit over the axles of my 2012 grand sport.

 

What are your ZR1 headers? I know what ZR1 exhaust manifolds are, and I know that you can buy headers of various brands that fit a ZR1.

 

Again in the original post, arh zr1 headers. American Racing Headers fitted for a zr1

 

A clear example of you not reading or communicating carefully.

The "over-axles" as you call them are part of the muffler. Some companies leave them loose to ease install, but from an OEM perspective they are all one part. If you have 3" pipes, they will fit all the 3" (aka Z06 or ZR1) intermediate pipes out there.

We know you have a GS. Want a 3" exhaust? Read this thread
Swap out the LS7/9 exhaust manifolds/cats for your Z car headers, buy the correct intermediate pipe for those headers, and bolt on ANY Z06 or ZR1 mufflers, OEM or aftermarket. As mentioned above, I suspect your issue is that you have the wrong intermediate pipe.

Since you are clearly confused and don't know what your asking about.....The geometry changes are on the passenger side of the 2009 & up base & GS intermediate exhaust pipe and the muffler over-axle pipe. The car geometry, attach points, etc are the SAME on the GS as they are on the Z06 and the ZR1.

The actual, literal, no sh*t, we're not kidding exhaust PIPE is what changed. You're so f'ing wrapped around the axle about a geometry change yet it doesn't even apply to you if you're using a full OEM or aftermarket Z06/ZR1 exhaust.

Lastly, if you were trying to use any base or GS exhaust parts with your Z headers, then it's a hack job. Doesn't matter if you spent $25k on mods. You would be trying to force parts to work together that require cutting, massaging, and adapters to do so....aka hack job.

Go buy the right intermediate pipe, if your over axle pipes were loose from the mufflers ensure you're using them on the correct sides, and quit worrying about a geometry change that doesn't apply.

 

Everyone has pretty much made clear the differentiation between the systems. Since geometry seems to be the issue, I'll explain.

On the passenger side of the car (base and GS ONLY) the passenger midpipe discharges at a different angle on 09+ cars. The corresponding muffler matches up. This is why 09+ axles back systems are incompatible with previous years. I uncovered this issue when installing a rear mount turbo system designed for an LS2 onto a '12 GS. It simply required cutting, rotating, and welding the axle pipe, but that is what is going on here. Everything else matched up. As said, you won't be dealing with this design change anyway if you go to a 3" system, so the point is moot.

 

Simple question OP, what is the pipe diameter on the axle back you purchased? If it is 3" then you have the correct axle back. If it's not 3" then send it back. It's the wrong one. The 3" design geometry never changed over the years. You will want an exhaust made for a Z06 or a ZR1. I am guessing you ordered a 2.5 axle back exhaust which would work on your grand sport but not with the ZR headers and X pipe.

Next how big is the connection point where the X pipe connects to the axle back? Again if it is 3" then it's the right one. If it's necked down to connect to a 2.5" then it is the wrong one regardless if it's made for the 05-08 or the 09-up. You need the X pipe made for the ZR1 which I'm guessing you have.

 

Ok so speaking with borla I figured out the problem which is why I was so focused on the over the axle pipes. I bought a set used from a corvetteforum member. Turns out I have the wrong over the axle pipes made for the generation borla touring exhaust I purchased (there are two). The mufflers are the 1st gen but the over the axle pipes are for 2nd gen hence why they aren't even close. How that mixup happened is beyond me. They are a muffler shop so maybe there was some honest confusion there.
Anyways, I will be shipping this exhaust back and continue my hunt on finding one that will fit my car properly.

 

Just purchased an Akrapovic with 5" carbon tips to ensure I didn't have a hacked exhaust

 

If you told them you have a Grand Sport, you'll get the 2.5" system and you'll be in the same situation. Hope you specified the Z06/ZR1 mufflers or you get to hack away

 

Fortunately Akrapovic only makes their c6 exhaust for the zr1 and z06