Stainless steel exhaust system on R?

[HOT H2O]

The replacement exhaust from VW for my 1990 mk2 golf G60 was stainless steel. The none shiny one.

yes, 409. It can be polished but does not hold a polish well and will begin to oxidize regardless. Was definitely around this time (MK2 generation) that we began to see stainless across the auto industry.

304 will hold a polish better, but it too needs upkeep if you want it looking show car fresh.

 

[Willow1]

I here you vee dubber . I thought the conversation was about shiny exhausts,
Did Not did not realise the difference, this is the aftermarket exhaust I just took off my old car, which is sold as stainless steel,
Is this chrome plated 400 grade steel,or is it polished 309 grade ?
Which after 8 months use has no rust on it however the standard system looked like shit after 1.5 years,

 

[HOT H2O]

Willow,

Personally I have never heard of anyone chrome plating an entire exhaust system, usually they will chrome plate exhaust tips as that is what most people only see, and I don't think plating would hold up well on an exhaust. Looks to be you have the 304 stainless which has retained much of it's polish nicely, however I am also not familiar with Invidia?

Yes, 409/410 can begin to look like sh!t rather quickly, however unlike mild steel, 400 grade stainless when it oxidizes actually creates somewhat of a protective effect to inhibit further oxidation so rust perforation will not happen for a very long time.

I'm somewhat torn as I do like new, show car fresh bits, however I actually don't prefer 304 as it has an ever so slightly higher note, is slightly less malleable and therefore has a slightly higher risk of cracking/breaking especially at welds, stress points, hangers etc, and some manufacturers will use too thin a gauge which while is lighter, enhances all the negative aspects of this metal.

At the end of the day all I'm saying is do research before buying any company's design. Ask the gauge thickness, all metal types used (some mix and match), warranties expressed or implied, and what suits your needs best.

Cheers!

 

[Croc-Dundee]

Cheers guys - thanks for all the informed posts on this and the original question relating to the type of steel used in the exhaust system. Guess I'll know soon enough as I was informed today that the R is now at the port awaiting shipment!

 

[Willow1]

Cheers guys - thanks for all the informed posts on this and the original question relating to the type of steel used in the exhaust system. Guess I'll know soon enough as I was informed today that the R is now at the port awaiting shipment!

Jealous..... mine is built next week are you going to wait for the new reg in March ? I spoke with some VW technicians and they said the exhaust is made from mild steel and does not match the grade of stainless steel,
How ever they do use rust inhibitors in the metal/ info from senior master technicians

 

[Croc-Dundee]

Jealous..... mine is built next week are you going to wait for the new reg in March ? I spoke with some VW technicians and they said the exhaust is made from mild steel and does not match the grade of stainless steel,
How ever they do use rust inhibitors in the metal/ info from senior master technicians

Yes, will wait for new reg. date, also as the tracker indicates three weeks delivery time approximately to dealer currently, plus pdi when it gets there, so timing just right really. Apparently I'll possibly be the 1st getting mine and before they get their own R demo vehicle. I'm sure you won't be jealous once your own arrives...not long now...but just hope we don't experience some of the same issues reported in other posts. Interesting info about the exhaust issue - still not sure what the reality is as opinions seem to vary depending on who you speak with. Anyway only one month to the 1st March

 

[HOT H2O]

Jealous..... mine is built next week are you going to wait for the new reg in March ? I spoke with some VW technicians and they said the exhaust is made from mild steel and does not match the grade of stainless steel,
How ever they do use rust inhibitors in the metal/ info from senior master technicians

I'd be curious to get clarification on this. They are correct in that the steel does not match the grade of 304 stainless, but the way they describe rust inhibitors 'in' the metal leads me to believe they are still talking about 409 stainless (which some people do not refer to as 'stainless' because it oxidizes rather quickly)

Now using a rust inhibitor 'ON' the metal would be aluminized, typically.. But manufacturers have not been using aluminized on exhaust systems in a long time for various reasons, mostly emissions and warranty.

People still often misunderstand what 'stainless steel' really means and they expect a stainless steel to not 'stain', sounds intuitive but it is not.

"Alloy 409 is a general purpose, chromium, titanium stabilized, ferritic stainless steel whose primary application is automotive exhaust systems. It contains 11% chromium which is the minimum amount for the formation of the passive surface film which gives stainless steels their corrosion resistance. It combines good elevated temperature corrosion resistance with medium strength, good formability, and overall cost. Alloy 409 resists corrosion strongly compared to carbon steel and is used as an alternative to carbon steel in mildly challenging environments where its high resistance to corrosion and high temperature oxidation gives an advantage. It is commonly used in applications where appearance is a secondary quality to mechanical properties and corrosion resistance."

 

[DW58]

This is starting to look more like a metallurgy forum by the day.