I have to replace the original exhaust sytem (cat, pipe/resonator and muffler) on my 2.4 LT (manual trans) in the foreseeable future because of rust. I would like to replace it with a quiet, mandrel bent, stainless steel system (I plan to keep my HRR for as long as possible). From what I have read in this forum and found on the web so far, the options seem to be rather limited:

- Magnaflow and Gibson: stainless steel, but most likely too loud for my taste
- Original GM: quiet, but expensive and doesn’t seem to be stainless steel (at least according to the rust I have (salty roads during winter))
- Walker: inexpensive. Muffler seems to be stainless steel, but pipe/resonator is only aluminized steel and not mandrel bent (https://www.rockauto.com/en/catalog/...resonator,5872)

Here’s what else I have found:

- Muffler Express: stainless steel cat (https://www.ebay.ca/itm/192419804833?ul_noapp=true)
- Mandrel Exhaust System: stainless steel cat (06-11 Chevy HHR - Downpipe Exhaust - 2.5" - Catted - Mandrel Exhaust Systems)
- Mandrel Exhaust System: stainless steel pipe, but the add on resonator option is Magnaflow, so may be too loud (06-11 Chevy HHR Exhaust Tubing System - Mandrel Exhaust Systems)

Of course depending on the supplier shipping to Europe may be a challenge, but may be solvable one way or the other.

Does anyone know other options or has experience with the options mentioned above?

 

If they sell Opel in Switzerland you might look at part available for Astra H, Zafira B, Meriva B they are all built on the Delta platform along with HHR, Cobalt, Ion, G5/G4/Pursuit/

 

If you want quiet stainless steel exhaust, It would have to be custom one. You can buy all the bent piping separately and than have a shop install it with the quiet muffler of your choice.

 

I was just looking at a high performance stainless steel exhaust header on ebay for the 2.4. Price was $60 but I guess shipping might be expensive. That would take care of that part. Someone on facebook just put one on and he reports an increase in power with no noise increase on the stock exhaust system.

 

OEM for GM was all Stainless after 1991 or 1992, I think. People have had flex joints rust, but the entire system should not.

Michigan is the salt capital of the world in winter, and I never saw an issue on my SS. 8 winters and 140K+ miles. We use multiples of what Europe even allows on the roads here...

The SS doesn't have that troublesome flex joint that the normally aspirated versions do, though. Is that the issue?

 

Pretty crumby stainless... Mine rotted away big time.

 

An option would be ceramic coat a standard exhaust system. Depending on the length they may be able to coat the inside and the outside.

 

It's probably louder than desired, but I found the MagnaFlow very quite... Too Quite, I couldn't tell it was much different than the OEM, maybe a little more lower tone but not in a range considered loud.
I haven't heard a Gibson yet, but it's regually reported as loud... which is my intended exhaust replacement.

 

The Gibson lets you know it's there...


As far as the OP's question goes... Why not get the 2 1/4 inch stainless Magnaflow and change mufflers if it's too loud.

 

Many thanks to all for the input!

On the stock 2.4 LT (manual trans), are the exhaust parts 2.25 inch or 2.50 inch? I guess all the exhaust parts (cat, pipe/resonator and muffler) should have the same diameter, shouldn't they?

Would a pipe with a Magnaflow resonator together with a quiet muffler prevent the "rumbling"?

Any recommendations for a quiet muffler?