6 replies to this topic

[milkandoj]

Here's some measurements to help identify what dump pipe (O2 housing) you have. I found info hard to find so i took pics at times when Ive had them side by side.
A quick way to narrow it down on the car, drop the front pipe off and measure the outlet on the O2 housing/dump pipe, evo3 is 61mm ID.... vr4 and evo1-2 are 55mm ID.

Note the differences also between the inner and outlet lip on the joins with the O2 housing, and the exhaust housing.These are often easily ported, such as removing the flame ring between exhaust manifold and exhaust housing. And the exit from an O2 housing where the front pipe bolts up.
So the inner lip is what limits your flow, and can easily be ported out to the outer lip size, in both cases.

O2 housings/ Dump pipes

VR4:
Main entry behind exhaust wheel: 55mm
Outlet to front pipe (outer lip): 55mm
Outlet to front pipe (Inner lip) 50mm


Evo 1-2:
Main entry behind exhaust wheel: 63mm
Outlet to front pipe (outer lip): 55mm
Outlet to front pipe (Inner lip) 50mm


Evo 3:
Main enrty behind exhaust wheel: 63mm
Outlet to front pipe (outer lip): 61mm
Outlet to front pipe (Inner lip) 57mm


The exhaust housing outlet size matches the entry into the O2 housing. The evo 1-2 and evo 3 are the same size in to match the 070 housing.
The vr4 inlet is smaller to match the 060 housing outlet.

The differences i can see with the evo 3 dump. (See pics in post below.)
Its very close to 2.5 inch on the outlet.
The flange surrounding the outlet is larger allowing for more porting potential.
You can easily port the inner lip out to 2.5 inch. Or you can take it out further. 2.75 inch looks achievable, some get it close to 3 inch apparently. But you'd be getting close to the edge of the flange and need some material for the seal.
I also ported inside the inside of the bend behind the exhaust wheel, where it comes in around the bolt holes. To keep it as close to 2.5 inch internally. This along with the 2.5 inch outlet porting is the basic porting, then you can spend more time from there.
The merge of the wastegate passage is also smoother than the other 2.


While we are at it some exhaust housing measurements.
060
Entry from exhaust manifold, (Outer lip) where the flame ring sits inside: 54mm
Entry from exhaust manifold, (Inner lip) to match inside the flame ring: 46mm
Outlet behind exhaust wheel into o2 housing: 52mm

070
Entry from exhaust manifold, (Outer lip) where the flame ring sits inside: 60mm
Entry from exhaust manifold, (Inner lip) to match inside the flame ring: 53mm
Outlet behind exhaust wheel into o2 housing: 61mm

Edited by milkandoj, 10 October 2010 - 10:47 AM.

[milkandoj]

Here's comparison pics.

Pic 1 of outlets to the front pipe: Top: Outlet of Evo 3. Bottom: Outlet of vr4. (Evo 1-2 looks the same as vr4 dump here.)


Pic 2 entries into the housing front exhaust housing: Left Evo 3. (Evo 1-2 looks the same here).Right Vr4.


Pics 3 housings and their matching dumps.Left: 060 and vr4 dump. Right 070 and Evo 3 dump. (Evo 1-2 dump looks the same at the entry)


Pic 4 Showing slight difference in angle for bolting up the font pipe. Left Evo 1-2 ( think Evo 3 is the same). Right vr4.


Ive got more pics of the E3 dump vs VR4 so the size difference can be seen. But my phone playing up. Ill get them up when i can.

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[akhirudin]

nice info.

[EVL20T]

Is there any differences between the wategate flappers on small 16 and big 16G?

[milkandoj]

Ive only seen a 14b 060 rear housing and big 16g 070 rear housing so can comment on a small 16g sorry.
If someone could add shots an measurement it would be great. Add to the info.
I put this all up because i was searching for it ages ago and its not compiled anywhere i could find. And what is actually an evo 3 dump compared to the others.

Edited by milkandoj, 11 December 2010 - 09:49 AM.

[rob323]

Is there any differences between the wategate flappers on small 16 and big 16G?

I don't think that the size of the flaps are any different, but the ports in the casting definately are. An Evo 2 dump pipe gasket won't line up with on Evo 3 Exhaust housing. And a VR4 (070) small 16G exhaust housing ports are different again.

[youda]

a evo3 big 16g has a larger flapper and port than a normal 16g turbo. Refer to 3zercrowd for exact meqasurements but i know there was a big differance.