Hummel206

Hi Guys.

In the search for a bulletproof flow optimised oil system on my 12A build I am thinking about blocking the oil flow to the front cover completly. Instead lead the oil out of the side of the iron and directly to the oil cooler. I would block the iron inside to avoid oil loss by the front cover pushing away from the iron.

So, as I didn't disassembled my car and engine (bought it in boxes) I have no idea if this is even possible, is there anything I need in the front cover i can't see ? As I can see the setup the oil feeds three things in the cover before it goes to oil cooler:

OMP - This will be removed and blocked and i will pre-mix.
Oil pressure relief valve - It is my undestanding that the rear one wil lbe sufficient, correct?
A little tube that seems to lead to no where ?

Thoughts on this mod ? Overkill ? Impossible ? Or worth the extra work.


Clear shot of the small oil feed thats leads no where.


The little oil feed ends in the small hole at the left on top, but what is it for ?

Looks like maybe something will be bolted to the engine here, can anyone confirm that ?

This was my idea. But maybe not possible.

j9fd3s

iTrader: (3)

its totally possible, but its not really needed. you do get rid of a couple of 90 degree bends, which is good.
you do risk ballooning the oil cooler when the oil is cold and rpm is high

Benjamin4456

I did part of this modification for my turbo 12A build, specifically adding the better outlet. I did debate blocking off the front cover completely but ended up not doing so for a couple of reason.

First, you lose your over-pressure relief valve. I decided this was important because I run 20W50 rear round and drive the car in weather below freezing, while also not waiting for oil to get all the way up to temp before taking off. If yours is just a summer/warm weather car, it's not as much of a concern. It's worth noting that the front and rear "regulators" serve different purposes. The rear is the actual pressure regulator, and it's responsible for keeping pressure around 70psi (stock) at 3k rpm and above. The front is an over-pressure valve, responsible only for bypassing some oil when it's too cold and thick to be regulated properly by the rear unit. As j9fd3s touched on, it's your "oil cooler saver".

The second reason folks tend to block it off is because of that darn o-ring. At high oil pressure the front cover deflects and it's possible for the o-ring to slip out and then get pinched, creating a huge oil leak. I got around this by using the metal front cover gasket from a 90-95 Cosmo with the integrated oil seal. The gasket for the 04-08 RX8 also works, although it includes the water pump housing gasket, which I didn't want to use. That portion could also just be cut off if you don't want it though. Anyway, without blocking it off you do probably still lose a little oil at high rpm due to deflection, but at least the concern for the o-ring taking leave is no more (and it makes assembly that much less stressful ).

Anywho, there's a couple extra factors to take into consideration. I think the improved outlet location is worthwhile for more in-depth street builds, but, as you now know, not the front cover block off.