exhaust manifold 100 turbo MC2 engine. (MB'ish??) - Page 5

4v6 · 29-11-11, 02:41 PM

My current thoughts on this are that itd be infinitely easier and cheaper to make any proposed design from heavy wall mild steel.
Its ideally suited to the job and could easily be ceramic coated to provide corrosion protection after construction.
Its far and away easier to weld it up, easy to cut and fabricate and will stand up to the temps encountered as long as its 3mm wall or more.
You can get such heavy gauge bends in schedule 10 i believe which is 3 to 4mm wall.
Hardest part as always is making it a like for like replacement, however id be inclined to remodel the wastegate feed pipe so that the manifold didnt vent from the end but centrally with a return pipe to the wastegate.
That way (if its possible to get it all in) youd retain stock fitment locations for the turbo and pipework but have the benfit of a properly controlled turbo, that wastegate venting from the end is a poor idea.

Other major benefit of using mild steel- low thermal expansion and lower cost.
the flanges wont warp to the same degree as stainless 316 ( mine warped like billy o) and the thing is going to be stable at elevated temps whears stainless moves all over the place although 316 is very unlikely to crack as a result, its more likely to start shearing studs and leaking.
You could of course weld it all up with 316l rods to give it great crack resistance anyway but hardly necessary i think.

No stranger to doing stuff like that but....

Might do one one day if i get the urge...... These were for the celica.

saladdodger · 29-11-11, 03:02 PM

They look like some great fabricated manifold mate

How much would something like this cost?

4v6 · 29-11-11, 04:02 PM

Quote:

Originally Posted by saladdodger

They look like some great fabricated manifold mate

How much would something like this cost?

Its that old length of string question

As ever initally probably expensive, but if the design could be worked out so that a minimal amount of cutting was required or maybe itd be possible to have them precut to just be welded up then thatd help.

Manifold flanges in mild arent going to be too much, its the time involved to get it right really thats the bugbear here.

the more i think about it, stainless is a poorer option tho.
If you think about how hard it is to fabricate up and then theres the issue of a a back purge with argon otherwise it carbons up, that simply dosent happen with mild.

As it happens i was asked to put together a couple of turbo adaptors (fag packet sketch) some time ago and i did those in mild steel and although they wernt the easiest thing to do they were very much easier than doing them in stainless....had no warp either so very much a go-oer i reckon.

Have to do a bit of checking and see what the parts cost would be in mild before comitting to this tho, has to be worth the time it takes.

These manifolds came out ok tho...

29-11-11, 02:41 PM	#41
4v6 Ex Member Classic Audi Club Member Join Date: Dec 2007 Posts: 5,565	My current thoughts on this are that itd be infinitely easier and cheaper to make any proposed design from heavy wall mild steel. Its ideally suited to the job and could easily be ceramic coated to provide corrosion protection after construction. Its far and away easier to weld it up, easy to cut and fabricate and will stand up to the temps encountered as long as its 3mm wall or more. You can get such heavy gauge bends in schedule 10 i believe which is 3 to 4mm wall. Hardest part as always is making it a like for like replacement, however id be inclined to remodel the wastegate feed pipe so that the manifold didnt vent from the end but centrally with a return pipe to the wastegate. That way (if its possible to get it all in) youd retain stock fitment locations for the turbo and pipework but have the benfit of a properly controlled turbo, that wastegate venting from the end is a poor idea. Other major benefit of using mild steel- low thermal expansion and lower cost. the flanges wont warp to the same degree as stainless 316 ( mine warped like billy o) and the thing is going to be stable at elevated temps whears stainless moves all over the place although 316 is very unlikely to crack as a result, its more likely to start shearing studs and leaking. You could of course weld it all up with 316l rods to give it great crack resistance anyway but hardly necessary i think. No stranger to doing stuff like that but.... Might do one one day if i get the urge...... These were for the celica.

29-11-11, 03:02 PM	#42
saladdodger Senior Member Classic Audi Club Member Join Date: Jun 2011 Posts: 1,030	They look like some great fabricated manifold mate How much would something like this cost?