I have a '13 GS with BB headers and x-pipe that the previous owner had installed. Additionally, he wanted to keep the NPP exhaust, which I get, but in order to get the 3" xpipe and 2.5" factory exhaust to mate they cut on the factory side to get it to fit up.....the BB xpipe has a different curve on the passenger side than the stock Hpipe I assume. Well I hate the welds and I live in a smaller town with only 1 good exhaust shop and he said really its as good as it's going to get....though he agrees it looks pretty crappy, he did not think putting money into it would be the best of ideas.

Now on to my question. I know the best bet is to just buy BB axleback, but I was wondering if anyone has mixed and matched xpipes and axle backs from different manufactures??? I am looking at Corsa, Borla, SLP etc etc. Just don't want to get into a situation of having to have even more fab work to get things to fit up.

Just looking for some input.

Thank you

 

If you buy the correct mid pipes (catted or non-catted) to go with the headers, they should bolt up to just about any axle back other than a Z06 or ZR1. If you want to use Z mufflers, you need the correct mid pipes (3"). You probably have Z mids now. Any decent muffler shop should have been able to fit the 3" mids to non Z mufflers with no crappy looking welds and weird bends. Sounds like your headers and your mid pipes weren't made for each other.

 

No....headers and midpipes fit just fine. They are both BB and that end is just fine. It's the axleback.

I get I may not be clear. So.....I have Billy Boat long tube headers and xpipe. Those fit together good. That end of the exhaust is all buttoned up and fits nice. The previous owner wanted to use the factory NPP axleback. The factory axleback is 2.5" and the Billy Boat xpipe is 3" (there is a clear size difference. Usually I would just see a reducer clamed to the xpipe and then the axleback cut enough to allow for the reducer and clamped or welded together. What I saw when the car was on the lift....it appears the Billy Boat xpipe has a slight bend to the passenger side (it has not been bent...it is the way it is from Billy Boat) and because of that slight bend it would not meet up properly with the factory axleback. The shop that did the work (by the previous owner) cut like 3 small pieces of pipe and cobbled that together to make the transition. Plus they just welded that pipe to the clamp....never have seen this before....instead of using a reducer.

Long story short, I'm not caring so much about the factory NPP axleback at this point.....so let's forget that point right now.

Will any 3" axleback work with Billy Boat x pipe that has not been modified, I am sure that others have done this and I am wanting to hear what they did.

I have run into this problem with Coyote mustangs....not all manufactures cut things the same length. The example I will give is I had AFE axleback on the mustang and then had cat delete and xpipe from magnaflow and they did not want to meet up....had to do some cutting to get everything to fit up nicely.

 

You have me puzzled. I have Kooks 1.875" long tubes leading to Kooks 3" mid pipes (for ZR1/Z06) and finally to stock ZR1 mufflers. I've also had Z06 mufflers on this same base model LS3 powered Vette. Fit was perfect both times. Any stock or aftermarket axel backs made for a ZR1/Z06 is a bolt on proposition with the correct mid pipes. I don't know why Billy Boat would be any different vs Kooks. Good luck getting this lined out. I understand the frustration.

 

Maybe the BB system doesn't take into account the change to the passenger side that occurred for 2009-2013, or maybe the original purchaser bought the BB system for 2005-2008.

 

Both of those could be correct. Thus my concern about moving forward on any other axleback.

I can see the BB plate on the xpipe....I'm going to get the car up later so I can see if there is a part number on the plate.

 

Remote possibility, but it could be the correct midpipes for your year model, but with 2008 NPP mufflers. Might check the muffler numbers while you're under there.

 

Update. Looked at Billy Boat plate on the x-pipe.

I have a Z06 catted xpipe that bolts up to my headers. Guess Billy Boat made LS3 headers that had 3" collector

That explains why the factory NPP axle back would not bolt to the xpipe. The Z06 xpipe has an extra kick to the passenger on the passenger side at the rear from my understanding.

I'm assuming moving forward I just need to get Z06/ZR1 axle back....correct? Mounting is the same I assume?

 

Let me ask this, does ZR1/late C6 Z06 axle back mount the same as C6 Grand Sport exhaust? I am assuming the easiest route to get the axle back corrected is just to buy aftermarket ZR1/late C6 Z06 axle back as I don't want to go into replacing the Xpipe since it is in like new shape and I can easily identify what I have....Billy Boat part number FCOR-0434.

Just looking for clarification on the mounting of the axleback.

Thank you

 

As long as you have an M6 transmission any axle back made for any C6 Z06/ZR1 should bolt up as you have the correct X for that app. Makes me think you have a set of NPP mufflers from a 2008 Vette. They are different vs 2009+ NPP mufflers. 2009+ NPP's should have been a more seamless fit without any crazy angles...just reducers. Z mufflers will fit if you have an A6 transmission. Just takes a little "clearanceing" to get around the transmission on the passenger side IIRC. That's on the OEM stuff. Not sure on aftermarket mufflers.

 

Sorry guess I missed that....I have a M6 transmission.