Got my HKS T04Z delivered from Japan, but it has a 'hole' between the two ports on the (divided) exhaust flange. I'm not sure if this is a manufacturing fault or just part of the design. Here's a photo of it. Does anybody know why HKS would do this?

Adrian

 

That is not a flaw, it allow expansion and prevent the housing from cracking.

 

Yup, especially if used on a collected manifold...

 

Could you give the measurements of the wheels in mm. Compressor in/ex and the Exhaust wheels in/ex?

 

So the exhaust gases passing thru this 'hole' won't disturb the gasflow nearby (ie. into the (divded) turbine housing)? Or overheat up the part of the gasket that's near the 'hole'?

S3DF, fyi here's the HKS T04Z specs:-
http://www.swordfishgsx.8m.com/cgi-b.../T04ZSpecs.jpg

 

What do you mean by 'collected manifold'? Tubular s/s?
I have an FD3S and will use a custom manifold with a divided s/s T04 flange that's about 3/4 inch thick. Will this work well enough, or should I go 1 inch thick instead?

 

Same specs as T04r.

 

I saw a photo of an HKS T04S and this turbo didn't have this groove/hole on the exhaust flange? Why is this?

 

design feature on the HKS Z, equalizes pressure between the runners into the turbine housine espcially if used with a divided manifold

 

The HKS manifolds have a notch on the manifold side too. All normal.

Josh

 

That makes good sense.
But I wonder why I can't see the notch on Jason's photos of the HKS manifold (from rx7store)!
I'm confused about this...what's going on?

 

Old manifolds and turbine housings didn't have the notch, new one's do.

~Mike...........