Oil cooling CT12s?

[RAd28]

Has anyone had anything to do with oil cooling CT12 turbos? I'm contemplating turbocharging a VW motor, but obviously being air cooled there's not water supply to tap into... so the next best thing is oil... any obvious problems with this?

Cheers

[wilbo666]

They are inherently oil cooled already...via the HP oil feed.

If you're thinking about running oil through the normal water cooling passage...it could work... but the stock water cooling system doesn't really have much flow, its meant to works on convection when the engine is shut off is my understanding...

Not sure how you would replicate that with oil through the coolant passage...you'd want a large restirctor too otherwise you'd loose a lot of oil pressure!

My understanding was that the main reason manufactures went to water cooling was to stop the oil cooking in the turbo when careless drivers turn the engine off after a long hard drive (no turbo timer...)

The water in the turbo housing then helps to stop the oil cooking...

Personally I'd give the turbos a go oil cooled only (and fit a turbo timer)... if you cook one it isn't a huge investment / loss...

I recall some info regarding oil / oil-water cooling in the book maximum boost by corky bell as well BTW...

Cheers
Wilbo

[thechuckster]

The corky bell book basically says water cooling helps keep bearing core temps below oil coking (basically cooking itself into a non-lubricating and non-cooling solid charcoal mass) temps.

And if you give the turbo some serious stick, it helps remove the temp and return bearing core to something more sensible.

I have a scan of a graph (somewhere, not sure which computer) from the book showing bearing oil temps for oil-only and water+oil bearing cores.

You could try setting up a passive and pressurised cooling circuit (e.g. coolant to turbo, from turbo to a small radiator then to a holding tank then back to turbo)?

[RAd28]

Wilbo - Thanks for that info... wasn't quite sure how active the water cooling was. Might just give it a shot and see how we go.

Chuckster - If it sounds like too much trouble then it's not gonna happen Thanks for the advice though...