ASH8

NO, the Series I RX-8 has the same Oil Pump as an FC RX-7.

S2 Oil Pump is ALL new..

ASH8

BTW:
IMO it proves what I said way back on S1's, that with the Twin Oil Coolers and ALL that length of oil lines is very much part of "lower or poorer" Oil Pressures when compared to the FC RX-7 (same Oil Pump and By Pass Valves).

And Yes I know the OIL Pump is a Positive Displacement one, but it is also said that to increase OIL Pressure "flow restrictors" should be installed.

ALL these Oil Lines were negating any 'restriction' and flow devices in the "original" factory Oil Coolers.

What 9K has done is remove All the Factory Oil Lines and Oil Coolers that are a MILE away from the OIL PUMP and install a Single High Quality Center Mounted Oil Cooler (somewhat similar to the FC RX-7) with far less oil lines and much closer to the Oil Pump.

And look what happened, the results speak for themselves.

Having said that, I am not against Twin Oil Coolers that are mounted a MILE apart and far from the OIL Pump (S2's still are), but, where Mazda IMO failed was the OIL Pump should have been Upgraded from the FC size, to at least the FD's (or FC Turbo same as FD) larger displacement Oil Pump.

Again well done 9K!, you did what I was trying to say in another way by reverting to a similar FC type Oil Circuit...with great results...I bet you can't wait for Summer!

PhillipM

I've given my oil far more heat than most of you are likely to see, and the pressure stays up there at 90+psi, I can 100% guarantee it's not the thermostat causing the pressure bump - if it was the pressure would be lower where he's measuring it, not higher, and I don't have a thermostat.

ayrton012

I was thinking about the IN/OUT drilling (the oil always flow across in it) of the factory cooler integrated thermostat house. This, plus the long pipes cause together the restriction.

ayrton012

I was sceptic about that the rear regulator can not keep the max oil pressure in the engine, around its opening pressure data in these single cooler system.

NOW I FOUND THIS!!!! (attached picture)

The rear regulator opening pressure is 92,5 PSI !!!! The information comes from the European Service Book. We beleived that this data is 74 PSI. Until this time.


It is answered the question why PhillipM and 9krpmrx8 has 90 PSI max oil pressure in their modified oil cooling system. Otherwise it proves that the factory coolers-pipes system restrict the oil pressure so much that the front regulator opens earlier than the rear one.

olddragger

iTrader: (3)

no-- it has a range of opening from 78-92PSI--its not a on off deal--it opens gradually just like the coolant thermostat--and its much better that way. But at 92psi i wonder if any any oil is going to the filter?

As far as restrictions go= the 90 degree turns, the banjo bolts and the flat plate coolers would add up to a lot?
By getting rid of all that and using a tube flow cooler (higher efficentcy?) then the pressure will be what the pump can do?

The pump is a fixed output pump, but after it leaves the pump pressures sure can be affected as 9K has demostrated.

Since my oil pressures are simular to 9K's and Philip's until the upper rpm band--wouldnt that again indicate that its in the higher rpms in which we are having some lubrication issues?
This great work everyone is doing here.
Paul doesnt have the regulater kit ready yet but as soon as he does--one of them is mine.
od
OD

9krpmrx8

iTrader: (46)

To me the most restrictive parts are all the banjo fittings and 90 degree angles. Combine that with teh relatively small hose/pipe diameter and I thinks is easy to see why my pressures increased with shorter, thicker 5/8' hose. Also keep in mind that my cooler has -12AN fitting for feed and return that I put reducers on to get down to the -10AN (5/8") hose.

Also, after the initial install we were adjusting things (moving hoses, etc.) and fixing leaks and my system works better at providing "max out" oil changes too. It appears my system only leaves about a quart of oil in the lines and the cooler do to its position and the position of the lines. We came to this conclusion because after moving and replacing some hoses and relocation the thermostat I only had to add a quart of oil.

PhillipM

Has to be, the bypass doesn't shut the filter off, just diverts the extra flow, so there must be just as much oil going through the filter as it can handle.

9krpmrx8

iTrader: (46)

Does anyone know what the bypass of a 2009 filter versus a 04-08 filter?

Brettus

iTrader: (2)

All this talk still has me very confused because it goes counter to what I know about pressure vs flow.

If you make a system with much less restriction than stock there will be less resistance to flow . Less resistance to flow means lower pressure + higher flow .
But with a positive displacement pump flow will always be close to the same (disregarding any pumping losses) so only pressure can vary . And in theory , if you disregard the effect of any restrictors or thermostats - 9ks pressure should reduce , not increase .

PhillipM

Not if he's measuring the pressure after the restriction...

Brettus

iTrader: (2)

/\ true - that would be even less pressure than before it .

9krpmrx8

iTrader: (46)

I am measuring at the oil filter and the return line from the cooler goes into the oil filter neck.

Brettus

iTrader: (2)

as I understand it the oil flows like this ...........

sump > oil pump > filter > cooler > engine > fall to sump again .

The bypass valve/thermostat for the coolers is inside the oil coolers - how does your thermostat work ? Does it allow some flow below the opening temp ? I think I see what is going on now .....

madcows

As OD said, the oil bypass is progressive. So while it's starting to bypass oil ~70psi, it's not fully open until about ~90psi. So whatever your OP reading is, that is the pressure the inlet of the oil filter is seeing (and pretty much the oil entrance to the engine). So, the engine is certainly seeing oil at high RPMs, what is unknown is the volume.

In the case of being able to see higher op at the filter sandwich, I'm with Ayrton in thinking that the front oil bypass is opening in the upper rev range when using the stock oil cooling system. We really need to grab some pressure readings in front of the coolers.

madcows

My understanding is that it's

sump > pump > coolers > filter > engine

RenKat

30-40% of the cooling in a rotary is done by the oil.
Two things are required by the oil coolers to pull the heat out.
One is air flow through the cooler and two is oil flow.

This is why both the 3rd gen and the 8 have problems!
When the car is not moving there is NO air and very little oil flow through the coolers.
ALL other rotary car models have a mechanical fan always moving air and the oil cooler is mounted in this air flow.
Oil cooler fans can help but the mounting has it’s problems, the main thing is ducting if you just put the fan on the back of the cooler the hot air just re-circulates around in the wheel well, and if you don’t retain the rubber duct in front you loose some of the ram air effect and the fan air comes back around the front of the cooler.
So the oil coolers needs to be moved towards the center of the car and up a little then seal the front and make ducting in the back so the air will make it out of the wheel well, also ditch the fog lights.

That’s the easy part, the hard part is getting more oil flow through the coolers. The only time you get high flow through the coolers is when the rpm is high enough to get the bypass valve to open, also more oil is going through the oil jets to cool the rotors.

This I believe is why the oil pressure/VOLUME has been increased in the 09 model, and the use of the oil control valve. Another name for this valve should be oil bypass control valve (OBCV).

The oil flow at idle and low rpm is very small, the pressure is low and NO bypass oil to the pan.
Now because you can control the oil bypass electronically, that means you can bypass oil at idle and low rpm which means more flow (VOLUME) through the coolers = more oil cooling.

This still does not help the air flow problem but a lot more oil is going to and from the oil pan.

Sorry about my rambling style.
What I am saying is oil pressure is not the issue it’s volume.
You do not get high volume through the bearings.
The bypass valve does more than pressure regulation it also controls oil volume through the cooling system.
If you did not bypass the oil, the flow through the coolers would be a lot less.

9krpmrx8

iTrader: (46)

Here is a rough draft of my setup


I am considering some type of duct work and if you live in a very cold environment some type of cooler bypass would be needed to avoid overcooling.

Brettus

iTrader: (2)

cheers for that - i get it now

9krpmrx8

iTrader: (46)

The return inlet is on the oil filler neck below the filter.

Right where this factory banjo bolt is. I replaced it with an adapter that excepts the hose fitting on the return line.

ASH8

S1...11.4 to 17.1 PSI
S2...20.3 to 26.1 PSI

ASH8

Correct..

The S2 is the same, but, ALL Oil is Filtered before it goes anywhere near Oil Return.

9krpmrx8

iTrader: (46)

Thank you sir, do aftermarket filter manufacturers recognize this data? Are the 09 filters available yet?

ASH8

I am not so sure they do or will even make them, BUT, the filter is also larger, so I will ONLY stick with GENUINE and I mean they are Made in Japan ones...

And yes, I have about 15 of them...N3R1-14-302

9krpmrx8

iTrader: (46)

Hmmm, I will have to hit up the dealer.