Turbo Flange Over Lap ?

[Boosted Zed]

Recently we have checked a few stock turbo's as well as one after market turbo and noticed the flange of the turbo is smaller than the flange of the

exhaust manifold both stock and bling staino ones. So the gases rushing out fo the engine through the manifold hit a big edge of the turbo flange. Not good. Might we worth checking and grinding out and match porting if you are changing turbo's or having it off for any work.

See the pics as we found 2 to 3 mm gap. We found this by simply doing a test not suspecting anything and actually suprised to see how bad the overlap was. We found this problem by carefully tracing out the turbo flange and cutting out of card board and laid it over the exhaust manifold and it became very obvious. With this edge jutting out if would make a difference to flow as would create a lot of turbulence especially at high revs.

To fix this all you need to do is remove the turbo exhaust housing and mark out and match port to suit. FREE POWER.

Will check GTR turbo's asap.

[GTRgeoff]

John the GTR turbos flange is larger than the manifold flange (at least on a 32 manifold). Also needs a port.

[Boosted Zed]

I should ask James from Abrasive Flow as he match ports to head and turbo and extrude hones the GTR exhaust manifolds and mathces to turbo. I know he opens up the exhaust manifolds a bit going into the turbo.

[B-Man]

Pics ??

[B-Man]

Here are pics - I'll do it for you JP

[Bass Junky]

Would the Gasket be the right size?

[GTRgeoff]

It is Pete. The manifold has a lip that turns the flow and finishes in a sharp edge. Not a good situation for flow but they maust have had some reason. Anyway it's probably just for stock boost, and would be an impediment at greater boost levels/exhaust velocities.

[Bass Junky]

So for the turbo in having High Flowed, I should grind a nice smooth radius into the flange?......?

[GTRgeoff]

Sorry pete, that's GTR32.

Yours should just be port matched.

[Boosted Zed]

Yes the gasket is stainless steel and sits a little in from the edge.

[Bass Junky]

In from the edge of the manifold or in from the edge of the housing?

[Bass Junky]

What I'm thinking is: Get the turbo high flowed, and whilst putting it on, match everything up with a die grinder being careful not to get any swarf inside the housing.

[GTRgeoff]

Remove the housing. The matching should be done so there is a smooth a flow line as possible, but some things just can't be perfect.

[Bass Junky]

But I'M perfect..... How do you explain that?

[GTRgeoff]

justgetmemystuff.........

Too much time mucking with your project. Eye on the prize!!!

[Bass Junky]

Yeah Yeah.

Tabs will be delivered Monday.

Waiting on word about the other bits.