Designing my oil circuit

[itiejim]

I'm trying to plan the oiling circuit for the supercharged Rover K series engine I'm building and was hoping for some feedback please.

Some information: the supercharger is a centrifugal Turbo Technics one as fitted to their Elise supercharger kits (albeit now going in my Triumph Spitfire). When originally fitted I understand that there were two oil coolers - one for the supercharger circuit and another for the main engine oil feed.

I need to run a remote filter due to space constraints, as you can see from the (rather elementary) design below, I'm planning on feeding the two oil circuits from two separate outputs after the filter. Fittings will be to suit the individual items involved (ie 10mm?) banjo bor the supercharger feed and then the relevant fittings on the oil coolers etc.

I know bu99er all about fluid dynamics etc, so I'm feeling rather out of my depth on this, my main concern being that I compromise the main oil pressure feed to the crank. Any thoughts or feedback most appreciated.

[itiejim]

Thanks for your thoughts folks. I had reservations about the whole "double oil cooler" thing. Turbo Technics obviously thought it was necessary (albeit using two air to oil coolers), however, I'll have far better cooling available with the engine mounted in the front rather than the mod mounted affair in the Elise.

How about the below?

[itiejim]

Thanks for that, I'll see if Turbo Technics can advise on a suitable restrictor. Presumably it should be located as close to the main oil feed as possible?

[itiejim]

I don't really know, it may well have one. All I can see is that it has a small banjo bolt type attachment for the feed.

I've also been looking at some old info about this set up. It seems that the original design used an oil cooler in line to the SC feed, therefore I presume not thermostatically controlled. This cooler obviously had very little impact on overall oil temperature and, apparently they struggled with oil temperature on track. Therefore, for any serious use a second cooler was needed for the sump oil, hence the set up that came with what I bought. I think I can package both air to oil coolers, so will aim for that. Updated cooling circuit diagram to follow...

[itiejim]

Updated circuit to show dedicated, cooled oil feed to the SC and thermostatically controlled oil cooler to manage sump oil temperatures.

[itiejim]

Thanks for all the input, you're absolutely right of course about the drive for the SC, but the unit is one designed by TT (and badged either ROTTREX or Geotech) rather than being an actual Rotrex unit.

I'm not really sure how I'd go about driving a separate oil circuit- albeit I can see the benefits. I believe that the Rotrex units incorporate a pump in the supercharger. What sort of pump would I require?

Pragmatically, does my circuit (with the addition of another filter as you suggested) look like a sensible option?

Max_Torque said:

The TT supercharger uses a Rotrex friction epicyclic drive, there are no toothed gears, it totally relies on the friction generated by the compression loads from the annulus ring, passed through the planet rollers and onto the sun spindle. If you get too much slip, bad things happen!

Rotrex


Managing friction, but avoiding direct metal to metal contact in these units is key. Rotrex have their own oil spec, which runs i a separate loop (does not use engine oil loop). TT seem to run from engine loop, but this brings issues imo.

If it were mine, i'd run a separate loop, or at least a specific low particle size upstream filter and separate cooler!

(the cooler you run it, the higher the hoop stresses in the annulus and the bigger the clamp load on the drive) For a Rotrex drive, iirc (and it was a while ago) the drive was spec'd to run down to around minus 10degC (any lower and the annulus could fail or the sun shaft could get deformed)

Edited by itiejim on Tuesday 17th January 12:28

Edited by itiejim on Tuesday 17th January 12:39

[itiejim]

Thank you for the additional information.

My application will be principally for road use, flywheel and clutch will be lighter than standard, but not race-engine light and gear changes will be no faster than a sympathetically used Ford Type 9 can cope with.

Given the feedback, my understanding is that it's OK to build the system as per my previous diagram with the addition of an online filter immediately before the charger(?). I see there are a variety of these available, any advice on what grade filter I should use - 80 microns seems quite common.