After about 10 years the factory exhaust system rotted out. After replacing it with an aftermarket system, the Y-pipe and muffler rotted out again in just 2 or 3 years. I replaced the Y-pipe with a stainless replacement that I found on Ebay and it has held up fine since then. Now that I need to replace the muffler again (third time), I can't find a Stainless Steel version anywhere (I do not want to replace the entire cat back system).

Does anyone have a suggestion as to who makes a stainless steel muffler for a 2004 G35X?

For what it is worth, when I first replaced the system, RockAuto sent me a Y-pipe for a G35 (not the G35X) and it did not fit. So, while I have found G35 Stainless Mufflers, the do have the disclaimer that they will not fit a G35X.
Example of non-G35X disclaimer

Thanks in advance for any helpful suggestions

 

I'd just hit up a local muffler shop and ask them to weld in a replacement.

Then when you get home take it all back off and spray it with that VHT "Flame Proof" exhaust ceramic paint. That will help protect the new muffler against whatever corrosion it's getting into. Salty winter road driving?

You'll still need to touch it up again once per year because rocks and debris will take off paint on the bottom side but it can all be touched up in the future without needing to actually REMOVE components again.

 

Does that ground strap attached at the oem muffler flange keep things from rusting somehow? i swear my X stuff rusts so fast after that oem strap rusted off with my original flange. Shop welded the muffler to mid-pipe but now I don't have the strap. It really seems like the front mid-pipe flange and bolts are rusting abnormally badly. Maybe it's my imagination but why else did they have that braided strap on there....???

 

There could be some electrolysis but I doubt it. The braided strap is just part of their electrical bonding system to ensure that a live wire doesn't end up touching the muffler, then a technician working on the car gets shocked because he completes the circuit. Mostly it's ground fault protection for PERSONNEL, not ground fault protection for EQUIPMENT.

Sounds like you definitely need to be painting your exhaust, but now I'm curious is the rest of your undercarriage pretty rusty as well or JUST the exhaust?

If it's just the exhaust it could also be the fuel you're using, or if the vehicle only ever makes short 5-10 minute trips and the exhaust never gets fully up to temp to cook off the moisture that ends up inside it that can severely rust out exhaust components as well.

Ever see someone take off from a stoplight and a LOT of water comes pouring out of the exhaust? That's usually poor fuel.