mrb63083

iTrader: (4)

is one better than the other? is there any difference at all in the two? preformance wise? or are they just selling the stainless at a higher price cause it looks pretty...even though you don't really see it all the time

any imput?

fxxku

I think the mild steel will rust and ss will not, performance wise should be the same. It really depend on where are you located at. Like in California mild steel will good enough cause the weather is nice vs chicago or canada....IMO

user 84205

SS is much better in all ways the any other steal. Resistance to corrosion is good, durability, and good looks..

RotaryKnight

It's really just looks. I think SS does retain heat differently but you can always termal wrap your mild one before you install.

Enthu

iTrader: (1)

there a long thread on this already somewhere, just do a search, and it goes on to explain everything you are wondering.

user 84205

its more for corrosion. Most stock pipes are mild steel, and they end up painting the downpipe silver, and shortly after the paint is gone then everytime it rains here comes CORROSION<<<

twinturboteddy

Stainless steel is ridiculously light compared to mildsteel.

Like the weight of a small cardboard box light.

Where as the mildsteel is probably close to 20 pounds.

rotorbrain

if youre worried about corrosion on the mild steel piece then you should just have it powdercoated.

dgeesaman

iTrader: (7)

Density of mild steel: .283 lb/in³
Density of SS: .283 lb/in³

Strength is basically the same too, so if you've got a lighter SS pipe it's made of less material. This may be true, if the mild steel pipes are thicker to tolerate a bunch of corrosion without leaking.

Dave

BrianK

another: stainless expands and contracts more than mild steel, which means that an SS dp could put more stress on the connecting bolts than a mild steel dp (because the ss dp will expand at a different rate than the parts it is connect to).

All the differences between the two (including what I just mentioned), however, are minute... they may as well be exactly the same.

Malachi151

There isn't much difference at all, but piles like the M2 are American made and are straighter then Japanese pipes, which are made for right hand drive cars, so the American made ones are higher flowing, though I'm sure negligably so.

jimlab

Well, yes, it is made from less material, but that doesn't mean that it's weaker than one made from mild steel.

The weight savings doesn't come from the density of the material...

Mild steel (1010) - 0.283 lbs./in2
304 Stainless - 0.290 lbs./in2
316 Stainless - 0.290 lbs./in2
Titanium - 0.163 lbs./in2
Inconel 625 - 0.305 lbs./in2

It comes from the increased tensile strength...

Mild steel (1010) - 55,000 lbs./in2 (70F)
304 Stainless - 85,000 lbs./in2
316 Stainless - 90,000 lbs./in2
Titanium - 50,000 lbs./in2
Inconel 625 - 140,000 lbs./in2

Stainless is stronger and therefore can maintain the same strength with reduced material thickness, resulting in a lighter component.

kundo

Hey Jimlab what is Inconel 625? never heard of it.

twinturborx7pete

iTrader: (3)

Stainless Steel just doesn't rust, in high humidity climates like here in Florida its best to get the Stainless. The mild will rust out in a matter of months... get the stainless.. or buy mild and thermal wrap or jet-hot coat the s.o.b.

user 84205

why would you do this? It will still corrode from the inside.

Just get SS and save your self all the trouble... It only a tiny bit more expensive..

jimlab

Extremely expensive ****.

Inconel (NiCrFe) is extremely strong, but very brittle like Titanium. It resists fatiguing in extremely high temperature environments, and is commonly used for turbo exhaust wheels, exhaust manifolds, exhaust valves, turbo oil lines, etc.

The exhaust turbine wheels in your RX-7's turbos are made from Inconel.

richjackson7

mild steel can handle higher temps than stainless but it does rust.... get a mild steal one i make them...... and have it coated.

GoRacer

iTrader: (2)

Can't figure out why it isn't made in Titanium. I know it's more expensive but it's lighter and handles more heat, it would make sense to me. Moreover, you can get Titanium MP and Titanium race exaust but not a Titanium DP? ...what up with dat?

rynberg

Good point, I believe this is why most SS downpipes still use mild steel flanges.

BicuspiD

SS pipes are generally thinner wall, and you can hear the exhaust all the more.. more potential to "ring", especially at higher rpms.

Mild steel parts are cast thicker, to help, in many cases, NVH standards as well as lowering warranty claims by being more durable. And less expensive. A corporate dream

-Richard-

user 84205

You can get them, BUT damn they cost a BUTT LOAD!!!!

twinturborx7pete

iTrader: (3)

I still plan on ordering the M2 SS DP... easy install and plus its SS.

silvr94r2

iTrader: (3)

SS are lighter and have a little sound advantage IMO....i like the added note.

I have some SS Dp's and Mp's in stock ready to ship if anyone is interested. They have SS flanges and include gaskets. The price will be around the market value minus some $. I'm sure i can beat anyone's price.....did I mention that they are fully polished as well? They are very nice pieces! Welding is very good and clean.

dgeesaman

iTrader: (7)

I didn't go into that for a good reason: because you can get all kinds of strengths from both mild steel and stainless steel. To my knowledge, pipes aren't very strength limited, except for abuse by things banging into it. It's hard to say what kind of strength either pipe has without testing it or knowing exactly how it was fabricated. Remember, welding a 90ksi SS will make it into 36ksi steel around the weld area.

Dave

DamonB

I believe Iconel is what is used in F1 and CART exhaust headers. All the turbo applications are true as well as jet engines; the turbines and compressor fans in them are typically made of Iconel if I am not confusing it.

The metal is excited electrically in such a way when it is cast that the part is no longer a conglomerate of individual metal crystals bonded together, it is now a single crystal molecularly. Imagine a big *** turbo fan on a 767 being a single, massive crystal!

How it is drawn into tubes I am not sure, unless it is rolled into sheets which are then formed into tubes with the seam welded. Seems like I recall weld seams running the length of the exhausts I have seen.