Stainless Exhausts

[dpsubaru]

Does anyone know what grade of Stainless Steel is used to make Stainless exhausts? Am presuming it is 316L (anti-acid) type material but has anyone done this work before? Additionally, how is the stainless welded? Feed type material for the seam?

Also, and this may be a bit of a stupid question. Can the exhaust manifold be made from stainless material as well?

Any thoughts/comments welcome.

 

[obi_waynne]

I'm pretty sure i've seen a stainless steel manifold. It is harder to machine as there are so many joins but a good one is far more effective than a cast one. Get it heat treated as well, either a ceramic coating or a good wrap as it is off the car. You'll not get another chance to do as thorough a job.

 

[MasterAuron]

T304 is usually used for exhausts and yes exhaust manifolds can be made from stainless too. I have two sitting in my room, although one of them has mild steel flanges.

As for stainless welding, I'm not sure tbh as I've only ever welded or needed to weld mild so never looked into it plus I have a friend who can weld stainless for me if need be.

 

[boostnturbos]

316 is the normal grade of stainless steel that i use. i make ss lines for a living. you can get cheaper grades but they dont last, the 316 is lifetime guarenteed.

as for manifolds yes it is possible and you can pick them up cheap on internet but sumtimes they are weak and dont fit. In saying that i fitted 1 for a friend a while ago bought off ebay and fitted like a glove, cost a 1/4 of what i could have made it for so you can get a good deal from time to time.

on to welding ss, yes you can a number of diff methods are, 1) stainless steel rods with arch welder, 2) stainless steel wire with a MIG welder and 3) TIG welding is also used it costs far more and takes an experienced welder to do it but uv got a 1st class job done.

The preferd method for making stainless steel lines are with a ss bender, neater job no seams and good for flow but a bender an set you back over £20,000 so the line will cost more because of the costs involved for the engineer.

i havent got 1 as i preffer to use precast 90 degree bends because they cost a fraction of the price and the outer bend wall isnt streached an subsiquently weakend and thind cutting the life of the line in half due to tiny fractures caused by the bending process.

 

[dpsubaru]

thanks gents,

Pete, 316 or 316L as understood that "L" would be anti-acid. Am sure some companies selling on the cheap using 202 grade (only 4% nickel) so much lower costs but will corrode whatever they say.
In regards to "pre-cast" do you mean seamless stainless pipe as surely casting steel in the thickness required is very difficult and costly process?

On the welding front i dont know diddly squat but luckily my brother does MIG and TIG so he can get the job done. Worth an experiment or two - at least with the manifold side of things.

 

[boostnturbos]

sori yeah i ment 316l anti acid. The 90 bends are pre cast stainless steel with a 2mm wall, prices vary, 3" bend comes to something in around £9 a go, 2 1/2" is £7, 2" £5.50 thats mostly all i work with. Its nothing realy when you consider the cost of buying the bender to do the bends youself. I also make the odd lorry exhaust but the cost of the piping for that is through the roof plus you cant get bends- to my knowlage.

Trying a maniflod is extremly difficult especialy with stainless, lets hope your brother dosent give up after the 6th attempt, i did!

Hope that sorts out your q's on stainless steel.

 

[Country Bumpkin]

We use a TIG for all our stainless and aluminium welding, that covers exhausts and manifolds in stainless and stuff like intercooler pipes in either aluminium or stainless etc etc.
I agree with the earlier statement about e-bay manifolds, some fit, others need adjustment from minor to major surgery but if you get a good one cheap enough there's no way we can make them at that price.
The price of steel alone is expensive over here compared to what they are paying for it in China, they are buying in such bulk that we [U.K.] get what's left and really pay for it.

 

[dpsubaru]

CB: think the reason they can make it cheap is because for small applications like manifolds where you dont need a large area of steel they can use off cuts or more likely secondary material which is declassified by the producing mills - it is still the specified grade but maybe the coil weight is too low, the width is not correct, its an overrun etc... (plus not clear on overall import taxes in the uk for stainless products but this may add something to it)