Making A Dump Pipe

[SLAPS]

Hey All,

I currently have a 3" dump hanging off the end of my xr6t style rear housing however I wish to make it a little bigger

XR6T's have seen some really good gains around 300rwkw by stepping up to a 4" bell mouth dump from the usual 3-3.5" split.

So squashing/bashing/bending the 4" 90degree bend.

I figured I'd grab some plate to make a dummy flange, cut the flange in half having two of the flange sides on opposite ends of the pipe, then attempt to squash the pipe in to shape using the press.

The other idea was to grab some plate again except cut an inverted version of the flange (i.e inside of the flange) and then slowly bash the dump in and pull the top out to sit on the outside of my inverted flange. It should then sit nicely inside the proper flange.

Can any one provide any tips? Might have to head down and hire an Oxy I'm thinking.

Edited June 9, 2009 by SLAPS

[Craved]

i like the inverse flange idea, just would need to either cut your new flange hole bigger or the inverse smaller by the material thickness.

you going for stainless or mild steel?

got any pics of the xr6t bellmouth's you refer too?

[SLAPS]

I had a better pic of it.. The 4" appears to mould in nicely.

As for mild or stainless it depends what is available and which is cheapest. I have no issues with mild.

Pics attached of my current 3" dump. I tend to visualise the wastegate gasses smashing in to the path of the turbine wheel reducing turbine efficiency creating the boost drop issue I've always had regardless of power being made (before cams)

Edited June 10, 2009 by SLAPS

[Craved]

I dont think you'll be able to mash a 4" pipe to fill that hole.

the crease marks on teh x force one certainly make it look like the collector is welded on som 4" pipe, the rest could be sheet metal folded and formed into the required shape.

edit : prob better to cut the rear off the wastegate merge and extend this back around the Bend further.

[wht510]

Best thing to do would be to go down to your local exhaust shop, and buy some 90degree mandrel bend (or press bend for that matter) sections in mild steel. You can then cut the required shape out of the bend, and weld that in instead. That's what did when I made my custom stainless steel dump pipe for my SR20DET.

Plus you get a nice shallow flow path for the waste gate gases to merge back into the main stream.

[SABBAi]

This how I've done it in the past. Mind you, front wheel drive applications require more work and thought. Might givce you some ideas. I'd also run a long pipe off the internal wastegate and merge the pipework in smoothly as far down the front pipe as you can. Try to reduce the amount of turbulence and you'll reap the rewards.

And external gate setup

And the finish result

[boz_soljah]

nicee