Who has done this? I seem to recall NS Dev made an awesome exhaust. I have a load of stainless pipe lying around (few meters of straight and some 90 deg bends)

There are a couple of things I want to look at.

Exhaust configuration. I have a straight six engine, how would you have the exhaust? Something like this with 2x 3-into-1 collectors?



or 3x 2-into-1 collectors then a 3-into-one collector

I've MIG welded steel before (made my inlet plenum) and I was pretty happy with it. Maybe I could tack the whole thing up then get someone to TIG it for me.

I loathe working with stainless Cutting, drilling etc my inlet plenum was a long, drawn-out affair. How would I cut the pipes? I don't have a bandsaw or similar and obviously I'd want accurate cuts.

Also where could I get collectors/merge collectors from?

Thanks for any info

Making a good exhust manifold is an art, not just from a welding point of view, but getting all the pipes the correct and equal length. If getting the most from your endine is priority, i'd leave the manifolds to the experts, and concentrate on fabricating the rest yourself if you really want to do some.

IMHO... how you have your headers arranged is going to depend on the firing order of the engine...

but the TR6 engine I have is connected 1,3,5...and 2,4,6

SS tube is not too hard to work with, just take your time and cut it slowly with coolant.... You will need to get it tigged thogh!

Here is our home made system. It is Titanium from end to end. We started with two manifolds from the 929 Blade engine. These are Titanium as standard. Simply cut them up so that you have straight bits and curved bits.
Then simply make your own pattern of manifold. You'll need some titanium sheet with which to make the collector. The can is from a ZX12 IIRC.
This exercise could equally be done using stainless of course.
Or even mild steel if that is all you can weld.
If you can get the correct flange or flanges to suit your particular engine then this will give you a head start.
Your 6-2-1 is fine. I wouldn't worry too much about getting the pipes all exactly the same length either, although doubtless I will be decried for saying this. Concentrate on getting the joints right with no sudden changes of direction.
If you already have some suitable pipe then the overall cost could be minimal if you weld it yourself.
Geoff.

TBH I agree with Spyder, exhaust headers are a bit of a black art, and can cost an absolute fortune, for little percievable gain - on the road anyway.

I made my own from mild steel bends bought off here, equal length primaries but no specific tuning, they shouldn't flow any worse than the standard Focus pipes. Total cost was about £25, vs close on £400 for a specially made job...
Rescued attachment myexhaust.jpg

I made mine by cutting the flange plate of my old CVH exhaust and welding on a 4-2-1 set up. It was easier to do than I thought. Two helpful tips are to allow it to be seperated where it exits the car in case you need to remove the exhaust at a later date and to cut the pipes square with a hacksaw use a jubalee clip round the pipe
Rescued attachment Image054a.jpg

And mine

I went for 4 - 2 - 1 equel length, the lamda sits in the last collector. You will not get the perfect lengths as the cars are not long enough!

I made the collectors by splitting larger tube and welding in triangles.

Held it together with masking tape around each joint then spot welded through.

You have to be logical in order as some joins will be impossible once its all together.
Rescued attachment Zorst.JPG

Thanks for all the info

sorry to bring up an old post guys.

Whats the deal with unequel length manifolds like scoobies have?
i want to weld my own system for my zetec se... if i don't get it spot on and the headers are not quite equel will i end up with a car that sounds like an impeza or just a system that steels power from my engine??

also what thinkness steel pipes do i need to make my headers???

Scoobies are down to the boxer engine, as two of the pipes run from the front cyliders and two from the rear, so the total lengths are different.
If using mappable injection, then gains can b had from exhaust tuning, if not then stick exactly to the std lengths and design as incorrect lengths will lose power due incorrect AFRs, only slightly, as the scavenging rpms will be changed.

The alfa engine when in the 164 has the most ridiculous exhaust ever made.

The car is front wheel drive so transverse engine. The front front bank of the V6 has a longer manifold the the rear bank, and merges near the sump and goes under the engine.

The rear bank has a stubby manifold, and just kinds zip backwards straight away.

The only meet about 2/3 of the way down the car.

If you were to measure the lengths , they are all cery different.

On the other hand in the rear wheel drive versions with same engine, the are matched.

So, My opinion, if you can get them something like equal. bis bosh job done

I have a set of eaual length matched stainless one tho