Making your own custom turbo dump pipe

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Making your own custom turbo dump pipe

Post by shanec86 » Wed Aug 09, 2006 7:00 pm

Making your own custom turbo dump pipe
by Shane.

Take one look at the factory dump pipe and you can soon see why you would want to replace it, a cast piece with an extremely tight design, this greatly limits performance.

In this guide i will show you my first attempt at a 3" dump pipe. Keep an eye out because soon i will be revising this to include a split design incorporating a wastegate screamer pipe :D

Parts Used:
1x 180degree Mandrel bent 3" mild steel tube
1x 8mm (although 10mm would be better suited) Flange cut to suit.
4x High tensile 8mm Allen Key Bolts

Tools Used:
Various Spanners/sockets to remove dump pipe
Suitable Allen keys for the new bolts
1x Angle Grinder
1x Band Hacksaw (Handsaw could be used)
1x Oxy welder (used for its neater look(mig/arc also could be used))
1x Permanent Marker
1x Measuring Tape

First Things first, unbolt the standard dump pipe and front pipe if this is what you are using, then throw it as far as you can.
On the following picture, the red arrows indicate the nuts that you should undo remember to use WD-40/Inox so you dont round off the nut or snap the stud. Nothing worse than fixing either of these problems!
These were 13mm nuts used on myn. The Blue arrow is the standard Exhaust temperature probe, now dont hold me to it, but i think this is useless. I removed it on the standard ECU and the car ran perfectly fine untill i went to an aftermarket ECU.


There are 2 things you can do here
- Undo the probe out of the dump pipe, if you have a brake line spanner use that, because its going to be very tight!
- Disconnect the whole sensor from the loom, including the wire which runs above the radiator


Ok now that all the stock system has been removed its time to start measuring up and playing with the new pipe. First of all i cut the pipe i had into this shape, this is basically the direction the exhaust was going.


Next i bolted the flange onto the turbo, and sat the pipe in place. It obviously was too long and pointed straight at the block. i marked the pipe at an angle which was enough to bring the pipe away from the block and at the same time on a slight angle away from the Airconditioning unit.
The welds i made can be seen in the following picture


The 2nd part of the pipe brings the pipe further away from the air con and the block, the reason for so many welds is to keep the flow as smooth as possible. The 3rd pipe is much the same in keeping it away. Now for the 4th section of pipe, this was another part of the bend in the original pipe. This if you could imagine starts to curve the exhaust towards the bottom of the sump.

This can be seen a from another angle in this picture.


Back onto the 5th pipe section and this lines up the pipe work with the cutout in the bottom of the sump, at the same time it has been kept as close as possible without touching the sump, this is to keep as much ground clearance as i could.

Finally the last section of the dump pipe was the remainder of the original mandrel piece, if you could imagine the same thing as the first picture with the flange in it, this is basically what the last piece looked like.


All i used was the mandrel bend, i was suprised that i had EXACTLY what i needed to mate it back up to the rest of the exhaust that was on the car. It took about 3 hours all up to make, it took a little trial and error with all the bends in it, the angle grinder was used to take little pieces off when it needed adjusting.

All up it cost about $50 and made a huge difference response, power and noise!

Completed Pics:


Last edited by shanec86 on Thu Aug 27, 2009 6:49 pm, edited 3 times in total.


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