Make your own downpipe for MK1 A1 chassis - PIC HEAVY!

[regcheeseman]

Start off with a 180 mandrel bend, they typically come with one end longer than the other

Cut off the long leg at a slight angle, you want the pipe to exit the turbo at an angle to achieve the clearance required

Weld on a flange – you can use the original one. With all the welding on this job, you need to do a lot of trial fitting to get it right, eye the job up, tack and check it. Oh watch out for the manifold studs, you need to be able to get a spanner on them!

Cut at 45 ish degree and rotate the cut off section through about 180 degrees and weld it back on – you need a bit of a dog leg, so check and tack up first.

Next step is fitting the 90 deg bend to return the pipe to point towards back of car – you may need to fit a small section of straight or angle the pipe slightly to get the pipe in the right place – I aim for the side of gear selector tunnel.

There, pretty much done – I add a 100mm section of straight then a flexi then another 100mm section. It’s up to you.

Here are a few pics of my first pipe fitted up to engine so you know roughly how it should look….and some of my later ones….

[lord_verminaard]

Wow!!!  Thanks for that, very nice DIY!

I'm guessing a Mk2 will be a very similar design?  I will have to tackle this sooner than later- you just made it look much easier than I had first thought.

What sort of welder did you use?  Looks like TIG.

Great stuff, thanks for sharing.

Brendan

[regcheeseman]

yep all TIG.

I did have access to free stainless and a TIG, about the only perk of that particular job - but I've moved on. Would love a TIG at home.....

[rallydiesel]

This is why this site is so great!

[regcheeseman]

would it be of use as a sticky or FAQ?

[1outof5]

Thanks Reg ! Whish I had your skills to do it myself.

Great stuff (that includes the diesel tach/rev counter mod)

[lord_verminaard]

would it be of use as a sticky or FAQ?

Ya, i'd say so, especially since nobody is making downpipes commercially anymore.

Brendan

[FoXBoXRaCiNG]

Props  

[Dr. Diesel]

Make sure you brace that badboy against the engine block, triangulated-like. Nice job!

[RabbitJockey]

would it be of use as a sticky or FAQ?

Ya, i'd say so, especially since nobody is making downpipes commercially anymore.

Brendan

false techtonics tuning makes them, but damn they are 345 now,  might as well have a shop do it for you at that cost.

[truckinwagen]

hell, I have built a couple in the dorm parking lot with a 110 arc welder and an angle grinder with a cutoff wheel.

they didn't look as nice as these (mostly due to the fact that an arc weld on thin steel looks like poop no matter how good it is) but paying any more than $150 is just crazy when you can buy a little welder and the materials for less than $200(and then you have a welder to fix and build anything else you might want later)

super good looking downpipes by the way, much nicer than the ones I built.

[dankcorey22]

Will this Work with 2.5" pipe?

[R.O.R-2.0]

Wow!!!  Thanks for that, very nice DIY!

I'm guessing a Mk2 will be a very similar design?  I will have to tackle this sooner than later- you just made it look much easier than I had first thought.

What sort of welder did you use?  Looks like TIG.

Great stuff, thanks for sharing.

Brendan

mk2 will have 2 more bends to clear the steering rack since its mounted on the subframe, instead of on the unibody..

[fatmobile]

That looks great but I like the idea of supporting it to the block,
 I use the early 4 into 2 into 1 downpipe supports,
  that bolt to the bock and trany,
  just before the flex.