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View Full Version : Porting Hotside of Hahn 20G



Nickallen1984
Monday 17th November 2014, 21:21
I recently took the plundge and bought Dream3r's Hahn Super 20G which I'm pretty happy with. I notice that the difference between the inlet on the exhaust and the outlet on the R manifold could do with some work to match them a bit but wanted some advice first...!

The T3 flange is square and the R manifold is round/oval. This will mean that there will be a flat wall that the exhaust gasses will hit on exiting the R manifold. Would it be worth matching these? The issue I see is that the turbo walls will be pretty thin once this has been done which may result in cracking of the housing. Has anyone done this? Is there a good reason why not if that haven't? I've got ported heads (Shem's engine), and I'm matching the inlet and exhaust manifolds.... it'd be a shame to then have this bloody great wall after all that work!

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.... get some calipers... I know!

claymore
Monday 17th November 2014, 21:36
http://www.ebay.co.uk/itm/OBX-Mild-Steel-Adaptor-FitFor-Volvo-T3-Turbo-Flange-to-Stock-4-Bolts-/111515821319?pt=Motors_Car_Truck_Parts_Accessories&hash=item19f6dc6507

Nickallen1984
Monday 17th November 2014, 22:31
Yeah I've seen these, I was going to machine the manifold to save on engine bay space, but both this and the adapter both have the same end result of a flow killing wall from hell at the top and the bottom of the inlet...

claymore
Thursday 20th November 2014, 21:39
I think you're looking at a problem that really isn't there just port match as best you can, although I've had no problems with my gt3076 without porting it and still get an easy 435bhp.

Nickallen1984
Thursday 20th November 2014, 22:33
Awesome, The US guys on Sweedspeed day that machining the lip flat indeed of putting the flange adapter on matches it well enough.... Seems that these combined responses have answered my question well.

I'm going to port the wastegate next to prevent boost creep - think it is with it or not?

claymore
Friday 21st November 2014, 07:43
I don't know what the wastegate is like on that turbo, but if theres plenty of metal around the hole, then it can only improve things, I know on one of my turbos I couldn't get a dremel anywhere near the wastegate to port it out.

Nickallen1984
Friday 21st November 2014, 08:22
Thanks claymore, sound advice. I also saw your car at retro rides this year... That is some rediculous engineering! Bravo!