Turbo down pipe, best solution?

Kai · Posted: Fri Mar 19, 2010 8:04 pm Post subject: Turbo down pipe, best solution?

So I'm on a big push to get this thing finished now and one thing I need to tackle is the center pipe reaching from the turbo exit to my back box inlet.

This is what I've got from the Subaru donar car

What u want to know is should I leave this pipe as is and simple extend it to the backbox or can match port it to the same size as the turbo outlet?

Now I've read that by matchporting the down pipe inlet it's best to provide a wall between the turbo outlet and the wastegate. The gases should be allowed to blend into one another as opposed to being flooded into the same pipe like mine currently would.

Also if I use the down pipe in it's current orientation it pretty slow to my cv joint/boot. Is this too close to you think. I intend to wrap my exhaust. But it still looks too close.

Thoughts please
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Kai · Posted: Fri Mar 19, 2010 11:33 pm Post subject:

Been looking at Subaru down pipes on eBay and it appears that an oe sti wrx impreza has a similiar down pipe flange to what I have. Only the aftermarket ones are different. I realise it's possibly for production costs that it's like this but if it was good enough for the STI motors then it'll probably enough for me.

The gap between my down pipe and the cv we've also decided is tok small so I'm going to chop It about some what and bring it round on the other side of the cv joint and head outback toward the back of the motor.
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gazman · Posted: Sat Mar 20, 2010 4:55 am Post subject:

If you made a dump pipe with an extra pipe for the wastegate (we used to call it a screamer pipe) it does make a reasonable difference in turbo performance by pulling exhaust gases away more efficiently, and keeps it spooling faster between gear changes. It also makes that cool fluttering noise that external wastegates make

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Kai · Posted: Sat Mar 20, 2010 8:09 am Post subject:

That's a pretty neat diagram there. The Drift guys I used to shared my workshop with used to create this extra/screamer pipe with all the Nissan they drove.

I realise the potential to gain increased performance here, is there any science to creating this extra pipe? I'm talking pipe diameter, length??? Or can I simply just add some pipe and attach it further down my downpipe.

I'd imagine there is a ratio between the screamer pipe diameter and waste gate diameter.

Well before I consider the screamer pipe I'm going to get the main pipe made up first. Then consider this once I've managed this as it won't prevent me from starting the engine.
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doppelganger · Posted: Wed Mar 24, 2010 7:22 pm Post subject:

ive done the screamer pipe on my race car Happy

and wolfrace do a bell mouthed flange for turbo's ,i have one on my caravelle turbo Happy

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richbaker78 · Teacher of Padawans Joined: 31 Jan 2006 Posts: 1298

mines kind of inbetween - like you i wasnt happy with the wategate being blocked by the zorst flange so i used an aftermarket pipe as a donor. It has a twin inlet from the turbo a bit like the screamer pipe set up except that the pipe re-connects into the main exhaust....

easy-does-it · Posted: Thu Mar 25, 2010 8:11 pm Post subject:

.... Great............ something else i now want to do before i get it on the road... Laugh Out Loud

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Kai · Posted: Thu Mar 25, 2010 9:38 pm Post subject:

Kai · Posted: Fri Mar 26, 2010 9:11 pm Post subject:

Ok well been a bush bee today. As you can tell I'm saving the best till last. I haven't quite worked out the screamer pipe yet nore the actual down pipe but it's coming along like a patch work quilt Laugh Out Loud

The high light of today's activities was cursing myself for not getting a 45degree mandrel bend. But then I realise I would cut on oh my 90bends in half getting not one but two 45 bends. How's a clever boy huh.

The almost finished product

I don't advertise my welding skills lol

I'm only showing you that weld cause it does get better

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Kai · Posted: Sun Mar 28, 2010 12:22 pm Post subject:

Whoop whoop, it's kinda finished. Well enough to go onto the car and do its job but I'm going to wait so I can create this screamer pipe. I'm thinking of using a type 1 J tube to create the pipe.

Anyway.......