Budget VS Longevity; Stainless Mufflers & Exhausts

[BR3W CITY]

My project evolves constantly, but gets a big change every 3-4 years. I just did my new heads and headers on the truck, so its time to re-do my exhaust setup again.
I generally feel that stainless is the "final" solution for any long term enthusiast. If your equipped to weld it and can afford it (and your setup is finalized), then SS is the best choice all around.

Being as my setup changes, I generally opt for mild steel. Its available everywhere, easy to weld with anything, and in summer-use hot rods etc, it lasts plenty long.

So what I'm really wondering is; how do you guys feel about mild vs stainless for mufflers specifically?

Since my headers are mild, and my pipes will most likely be too. But I'm debating mild vs stainless on my bullet mufflers, both DynoMax and Magnaflow. Partially I think the extra cost might be a waste on a a mild steel exhaust...but part of my also thinks that the stainless mufflers build quality might last through more than one era of changes.

My current stainless Magnaflow bullets are probably around 7-9 years old. and one JUST got the "rattles" inside or I'd consider reusing them on this setup.

So, a little discussion on the topic in general, as well as my particular query; you may proceed gentlemen.

[hotrod 80]

I have Stainless Borla straight thru mufflers with aluminized pipe . Problem is none mandral bending the big pipe .

[Marv D]

One problem with stainless is it will rust anywhere it comes in contact with a ferric iron / steel. So you need to make sure your hangars, mufflers etc are all stainless. AND TIG weld or at least MIG with stainless wire. Food grade stainless is purged of air on the inside, then TIG'd. Keeps the inside of the weld as pretty as the outside. You'd be surprised how the inside turns out of not 'process' welded like this.

Is it worth the $ and effort???? ,, IMO ABSOLUTELY if your willing to spend to do it right. If for no other reason than that 'ring' of an exhaust note that seems to come from a stainless system. Have 3" stainless borla's on 2 vehicles now.

[BR3W CITY]

Originally Posted by Marv D

One problem with stainless is it will rust anywhere it comes in contact with a ferric iron / steel. So you need to make sure your hangars, mufflers etc are all stainless. AND TIG weld or at least MIG with stainless wire. Food grade stainless is purged of air on the inside, then TIG'd. Keeps the inside of the weld as pretty as the outside. You'd be surprised how the inside turns out of not 'process' welded like this. .

Ya in my home shop I'm only setup for MIG (but I can run SS wire). I have done some tube on TIG using a dual-reg and purge dam when welding SS pipe before.

What weird is that right now I have the (old) Mangaflow SS mufflers, but a mild steel exhaust and never had a reaction (galvanic?). I think the inlet and outlet on the muffler are actually mild steel, and the welded with 309l or Silicon bronze or something, since the center section is definately stainless.

[vin63]

Having worked at a couple of header manufacturers and built many headers myself, I've always gone with mild steel and used a ceramic metallic coating - I have built stainless headers for specific customer requests. My reasoning for going with mild steel on my own stuff is the extreme heat cycles in racing that can contribute to heat-related fractures/failures in the more brittle materials and I don't live in a high humidity region. I see a lot more stainless headers develop cracks. My headers on my old Super Gas car showed no signs of corrosion or damage after 20 years of racing. My radiator hoses were made from the same mild steel tubing and were also ceramic metallic coated, and showed no signs of corrosion being subjected to water. I do run stainless mufflers on all of my hot rods, particularly Borlas. Stainless from the muffler back will help with the longevity of the system as you were asking about.

[jayoldschool]

If it's not going to be a daily driver, and will not see driving on winter salted roads, regular aluminized pipes and mufflers will last just about indefinitely. The full dual exhaust on my 71 was put on in 1991, and is still shiny.

[BR3W CITY]

Vin, is that sort of coating something a regular powdercoat shop would handle? Do you have any idea what it would cost? Due to my short run, my whole exhaust including headers has come in way under $800, so I'd definately consider coating it.

[vin63]

Originally Posted by BR3W CITY

Vin, is that sort of coating something a regular powdercoat shop would handle? Do you have any idea what it would cost? Due to my short run, my whole exhaust including headers has come in way under $800, so I'd definately consider coating it.

Yes, most powder coaters offer several different types of ceramic metallic coatings - most do, but double check to make sure they coat the inside of the tubing as well. The cost varies a bit, but the shop that I use the most charges between $100-$200 for headers, and then by the length for the rest of the exhaust tubing. Here are a couple of different versions of ceramic metallic coatings: my zoomies are the matte black, and the radiator hoses for my C10 are sterling silver. The shop I use also has a cast iron color which a lot of restorers use on exhaust manifolds for a factory appearance.


This is the sterling on the headers and exhaust tubing for my C10:


Found a photo from a fellow Pontiac friend that shows the cast iron color:

[BossHogg69]

I went the same route Vin63 did on my '69 - ceramic coated headers (Hedman Elites), Borla XR1 ss mufflers, and used a 3" Flowmaster mild steel/aluminized kit that I mig'd at home, then had the exhaust system ceramic coated (matte black) at my local powder coater. They said it was good for 1200*. Not a daily driver, just a money hogging toy. Other than the mufflers turning a little bit of a gold color, everything still looks good.

Now, on my daily driver ('05 GMC 1500, 5.3L) I have SS longtubes, aluminized pipe and mild steel mufflers - Flowtech Terminators. It's been on for 3 years now, the pipe and headers still look nice, but the mufflers already looked ragged out.

[BR3W CITY]

Vin- those finished looked like the turned out really nice. That cast finish would be killer on a sleeper, make everything look "old"

Both the black and the silver look like good options as well. I ended up ordering all the stuff in mild anyway, so I might have to get mine coated.

[cableguy0]

I work in an exhaust shop. Stainless is being eaten by this garbage fuel we have. I personally wouldn't bother with stainless. You can do 2 or 3 aluminized systems for the cost of 1 stainless system. Stainless doesn't last indefinitely. Factory stainless pipe rots out regularly. Stainless is also brittle and prone to cracking. Stainless is a pain in the @ss to bend without a mandrel bender.

[BR3W CITY]

I agree with you about bending/flaring/working stainless and its propensity for cracking.

But I'm curious about the "being eaten by fuel". Is that anything to do with the grade of stainless being used? When I worked for the steamfitters union 7-8yrs ago, stainless is standard in all food and medical process pipe, as well as in industrial applications in which ethanol and methanol (both liquid and vapor) were used.


Vin- I got a quote from a local shop that does ceramic coatings. They quoted me on the headers and 3x 2ft pieces of 2.5" tube

satin black, titanium,cast iron grey, and shinny aluminum which has little extra cost to it.
Headers $180
Pipes $75
In the shinny aluminum add $60
If you want the inside done as well (witch is a different coating than the outside) it's an extra $50 for headers and $25 for the pipes.

What do you think about his price? It seemed a little steep to me compared to my last powder job on some wheels, but thats my only point of comparison.

[cableguy0]

Vehicles cannot be compared to any other environment. Nothing else allows such drastic changes in temperature so quickly.Cars are their own environment. I can tell you aluminized pipe used to last 8-10 years and now it lasts 3-5 years. Stainless used to last indefinitely and now it is rotting out.

[vin63]

Originally Posted by BR3W CITY

Vin- I got a quote from a local shop that does ceramic coatings. They quoted me on the headers and 3x 2ft pieces of 2.5" tube


What do you think about his price? It seemed a little steep to me compared to my last powder job on some wheels, but thats my only point of comparison.

Was that Classic Coatings or Racine Flame Spray? That does seem a little pricey with the charge extra for coating the inside of the tubing. Check with Jet-Hot Coatings. Back in the 1980s, they were the only company providing ceramic coatings, and we all had to send our parts to them. Check also some of the other coaters that are outside of your immediate area...for example, I send my engine bearings and some of my firearms-related parts to Calico Coatings on the east coast. There is Performance Coatings in Washington that does a lot of volume for out of state orders.

[BR3W CITY]

That was from NorthStar machine&coating. They advertised doing the ceramic so I called there first.

Classic Coatings puts their prices up online, and they wanted $300 for a set

[OutlawDrifter]

Originally Posted by Marv D

If for no other reason than that 'ring' of an exhaust note that seems to come from a stainless system. Have 3" stainless borla's on 2 vehicles now.

this, in my opinion, is due in part to having a thicker wall, especially in the case of 304 stainless. any heavy wall pipe will give you a more distinct sound.

i agree with mild/aluminized pipe. moisture seems to collect in mufflers, and for that reason i like using stainless in that area. i used coated headers on my ls build and absolutely love them, the rest of the exhaust pipe is aluminized and painted with hi-temp rattle can paint. after almost 4 years the headers still look new and the exhaust pipes have some minor rock chips etc. ceramic coatings get my vote over stainless for sure.