Stainless for a fabricated inlet manifold

[smitty1]

Is there any reason for not being able to use stainless steel as a material for an inlet manifold?

If I was to make one, I have access to the equipment to weld stainless, and probably the material, but I havent seen any made out it.

I have searched on the net and in the forums, but haven't seen any real drawbacks to using it over alloy. Any ideas?

[takai]

Nope, no reason you cant. Main reasons cited normally are cost and weight. You have little cost advantage over alloy, and a significant amount more weight.

[wilbo666]

Stainless is much harder to work with than some other materials due to the fact that it work hardens. It is a PITA to cut / file / drill compared to alloy.

The cost of drilling / cutting stainless is also much higher than say alloy (the cost in cunsumables such as drill bits / cutoff wheels etc).

Generally people go for the easy to work alloy

Cheers
Wilbo

[feral4mr2]

stainless or mild steel is much easier for the average person to weld though over useing alloy.
i'm going to make a fibreglass inlet manifold for the feral's next 4agte when i get off my ass and do it.

[smitty1]

Stainless is much harder to work with than some other materials due to the fact that it work hardens. It is a PITA to cut / file / drill compared to alloy.

The cost of drilling / cutting stainless is also much higher than say alloy (the cost in cunsumables such as drill bits / cutoff wheels etc).

Generally people go for the easy to work alloy

Cheers
Wilbo

The reason I was looking into stainless is that more or less the bits that I would need to use to make a 4AGE inlet manifold would be offcuts or scrap. Also I would make it at work in my time so the consumable cost would be very little.
I can also weld stainless, but we don't have the equipment to weld alloy.
The extra couple of kilos that a stainless manifold would weigh over alloy doesn't mean that much either.

[wilbo666]

Like has been said there isn't any reason that stainless can't be used

I was just trying to point out some of the reasons (in my opinion) that stainless wasn't the option that most people go

If you have the material, the equipment and skills by all means go for it!

One other thing to bear in mind is that due to the work hardening effect of stainless I have heard that it is more prone to stress fractures than other materials....so perhaps some extra bracing might be a good idea!

Good luck with it.

Cheers
Wilbo

[jezza323]

fibreglass IM sounds like fun....id imagine you would need to lay a lot of layers to get what you want though...

[celicapain]

has anyone here tried makinf stuff out of carbon fibre? im thinking of making up some inlet ducting, and its doesnt look like (non-structural) things are to hard to build. similair to fibreglass but purtier

[feral4mr2]

fibreglass IM sounds like fun....id imagine you would need to lay a lot of layers to get what you want though...

fibreglass is prity strong. and an inlet manifold isnt of large are (the plenuim being of the largest area), so it wouldnt have to be too thick to be stong enough... even for boost.

[jezza323]

id imagine getting a good surface for the head seal could be a bit of a pain

also i was thinking how i could go about hanging quad bike throttles off fibreglass :lol: that would have to be decently thick

[joecoolmk2]

stainless also cracks from fatigue caused by vibrations. It needs to be supported reasonably well, otherwise it'll crack around the welds. And it also pulls/bows like a bitch when you weld it. you either have to pre-bend it to compensate for the weld, or secure it to a solid (thick steel) bench.

[Norbie]

A friend of mine has made several custom plenums in stainless, they work quite well but he only chose stainless because he works with it every day and has access to cheap/free materials and all the equipment. It made sense for him and it sounds like it makes sense for you, so go for it!

As mentioned stainless warps all over the place when you weld it but if you're used to working with it you probably know how to deal with that.

[oldcorollas]

when welding stainless, use low carbon grade, and you need to be aware of the weld area sensitisation stuff...

as for the work hardneing (and other fabrication stuff) of stainless, look here
http://www.azom.com/details.asp?ArticleID=1178
it seems the ferritic SS's are not much different to plain carbon steel, but the austenitic ones work harden faster.. but we are talking about actual deformation, not vibration (ie, reduction in area)

[feral4mr2]

id imagine getting a good surface for the head seal could be a bit of a pain

not if you know how to make flat smooth fibreglass surfaces.

also i was thinking how i could go about hanging quad bike throttles off fibreglass :lol: that would have to be decently thick

and again it's all in how you make the part.

[jezza323]

make me a manifold for the CBR600RR throttles which will arrive on monday then pls feral

i reckon glass would be perfect, could make any shape you wanted...pity ive never done glassing before though