Extrude Honing a turbo housing?

[cheekychimp]

When I was looking at extrude honing an exhaust manifold, something I remember from one of many threads I read on the subject was that extrude honing was best used on parts where normal porting was difficult/impossible. Someone said if you want to extrude hone something do the turbo housing.

So I thought about this. If you physically remove material I would think the effects would be similar to porting out the housing or clipping the wheel, i.e. more top end flow, laggier spool up ... BUT ... the poster suggested extrude honing the housing would reduce turbo lag /ubbthreads/images/graemlins/dunno.gif

Discuss!

 

[ktmrider]

There were some great articles about this when EH first became viable for commercial auto use ( around 2003 IIRC ).

Not only did they report increased HP, 10-20% depending on model and turbo, it also "increased" turbo efficiency. So you got both increased power and lower compressor-side temps. Spool was a tad lower too, less friction in the system.

At the time it was Extrudingly Expensive, mainly since there were very few companies in the US doing it.

Awesome stuff for irregular or asymmetrical surfaces like compressor housings and cylinder heads ( altho there were better gains on EM side of heads than intake ). Removes metal quite evenly and with fine media can create a very polished surface w/o removing a bunch of material.