Fitting dual oil filters

Over the coming months I intend to fit a remote dual oil filter setup, thermo sandwich plate connected to an air to oil cooler.

hope you don't plan to be putting them on to d22,which carries a cartridge oil filter,yours like to be for a canister type set up.

How are you going to compensate for the extra pressure drop to maintain design pressure at the big end and main bearings?

Dion said:

How are you going to compensate for the extra pressure drop to maintain design pressure at the big end and main bearings?

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what is the design pressure ?

have you had experience in this area either with this motor or others you might share ?

Not with this motor, but with a Yamaha Genesis 80FI (500cc inline twin, dry sump) we had massive issues with maintaining oil pressure at the big ends. Cost us three cranks. Our issue was to do with ext reservoir capacity and surge. The issue I would be concerned by is that the relief valve in your oil pump is calibrated to supply a pressure (i don't know what it is, only Nissan or Renault would know) at the end of the system (big end) sufficient to maintain adequate fluid film in the journal bearing. Another filter is a head loss that potentially needs to be compensated by an increase in relief valve opening pressure?

Why two filters?

The relief valve is designed to prevent over pressure mainly with over reving, when cold ...it does not regulate oil pressure at all when the engine is warm generally as this creates additional heat thus wasted power dumping over the relief.
The oil filters aren't inline they are connected in parallel , the oil velocity across them is halved , losses 1/4..additional losses with be incurred due to length of hoses and fittings...these are dependent on dia and viscosity..or shear rates

Going with twin filters as an enhancement to improve engine life and with 3/4"UNF thread a greater range of filters with different specs

Maybe as you mentioned your issues were more to do with oil pressure fluctuation resulting from surge

gazza414 said:

The relief valve is designed to prevent over pressure mainly with over reving, when cold ...it does not regulate oil pressure at all when the engine is warm generally as this creates additional heat thus wasted power dumping over the relief. The oil filters aren't inline they are connected in parallel , the oil velocity across them is halved , losses 1/4..additional losses with be incurred due to length of hoses and fittings...these are dependent on dia and viscosity..or shear rates

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Fair enough, in the picture the filter housing made it look like a series setup. Now that you say that about the relief valve, I agree as pressure ramps with RPM, but I would still see changing the head loss through the system as resulting in a change in pressure at the big ends, since there is no feedback loop from the pump to the end of the system and back to regulate pressure. You only have RPM to control the pump's output. Moot point as they're in parallel.

gazza414 said:

Going with twin filters as an enhancement to improve engine life and with 3/4"UNF thread a greater range of filters with different specs

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I understand the purpose of changing to the 3/4" thread for availability, I assume to improve engine life you plan on changing both filters in less than double the normal interval? Or the filters will have a different efficiency/bypass arrangement/micron rating to stock?

gazza414 said:

Maybe as you mentioned your issues were more to do with oil pressure fluctuation resulting from surge

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We know that now but at the time we investigated everything.