Increased Oil Pressure? Really needed?
 

Hey people

i have actually purchased the oil pressure mod, to go in with the supercharger, however under advice from Rohan (xtreme rotary) i decided to not put it in.

Basically he outlined the fact that increased pressure will also lead to extended heat and in the previous cars he has worked on especially race car he actually decreased oil pressure.

Basically stating that, if after the install i find the pressure is too low then it will be placed on free of charge, i found no reason to refuse the suggestion.

Whilst my car is a 03 model AT, i decided that it was in my best interest to put in a second oil cooler (known for decreasing oil pressure).

At the time i had my gauges installed including oil pressure.

Over the past month from my observation is that the pressure has been adequate.

During idle i will see pressure of around 15psi v 800-900rpm well inline of the recommended 10 psi per 1k rpm.

At cruise under slight load 2-3k rpm, i see around 40-50 psi of oil pressure one again inline.

At load of over 4k rpm it straight away jumps to 65 psi +

At red line (8.2k rpm) (at this stage i need to keep my eye on the road) i see oil pressure of around 110psi.

Now with these observation i can see that the oil pressure is very linear to increased load and rpm of the engine, so what purpose does the increased oil pressure really serve?

If there is no real benefit from added pressure, wouldnt it really just turn around and increase oil temps by frictional heat build up?

These are just my thoughts, wouldnt mind hearing some other facts from people that has looked at this (olddragger etc) and comment on their findings

Regards
Jason

If your rear regulator is working properly..it should bypass at much lower than 110 PSI

If you are getting that much pressure you don't need it increased

Makes me wonder what's up though? Maybe you have an FD regulator already??

no idea O.O, just reporting my findings

How confident are you in the oil pressure gauge?
If you really have 110 PSI max then you're good!

Pressure vs. heat makes no sense to me... unless he increased pressure by reducing flow... increased restriction.

The oil pressure mod simply raises the oil pressure relief limit allowing increased flow through the engine and coolers. In my view this should reduce temperature since the rotary is partially oil cooled.

110psi is suprising tbh, we only got about 92 or so even with the huge cooler and -12 lines.

Yeah when I went to the single Fluidyne my stock pressure went to 90PSI.

Dont quote me on this, but i thought the pressure mod increases the resistance therefore the oil requires more force to bypass it, therefore resulting in a higher pressure. Like i stated earlier i just had a real quick glance at it and didnt bother too much with it.

My thoughts were just like a garden hose, if u let it open flow comes out less quite slack, but if u cover it with a finger the water will spray much more strongly, please correct me if i am wrong, that was just my thoughts.

The reliability of my gauges? well i have the prosports ones, i have talked to flashwing and used his idea of a separate ground, the temperature gauges, boost gauges were all consistent with dyno read out, my average temperature during cruise at 100km/h oil at 70c water at 80c which is quite consistent to my knowledge over temperature during winter.

Now lets say the gauge is not 100% right (which i suspect anyways) and lets say my pressure was at 90 psi, at a red line of 8k that is still more then enough.

thoughts is appreciated

This is exactly correct and exactly why it is not a good idea.

and here i thought when mm replied, i was gonna get called a idiot :P

All the oil pressure mod does is raise the limit on the oil pressure...
It allows higher pressure before the regulators start to bypass oil.
There is no increased resistance to flow through the engine. There is nothing placed in the path at all. The only change is to the bypass path.
Below the stock opening pressure there is no difference at all. Between where the stock valve opens and where the Re valve opens there will be more oil forced through the engine passages and less out the bypass.

I see no risk to this mod.

With more oil forced through, it equates to more resistance as same amount of room, but higher volume of oil, therefore increasing frictional heat. With the oil already HOT there is not much extra cooling gained by the larger volume of oil, only more friction resulting in a higher build up of heat.

Not by saying "risk" i doubt the increased frictional heat will have an major adverse effect on your block, but as the title and original question states, what are the potential gains? of there is already enough pressure, and by adding more pressure there is no gain, but a slight adverse effect? that is where i am getting at.

Did you notice any difference in pressure once the 2nd oil cooler was fitted ?

to be honest, no.

my idle pressure is still the same and my redline pressure is quite similar.

my in between "seems" to be reasonably close, i choose to keep my eyes on the road!

I mainly use peak to see my pulls

hey - isn't it like 4.30am where you are ?

As I see it, the highest pressure I'll ever see is during a cold start.
What I want at that point is lots of oil flow and nothing out the bypass. This means pressure and lots of it. I don't mind if it heats the oil in this case.

When the engine is hot and the 5W30 (in my case) oil is thin there will not be enough pressure to open the bypass and therefore there is no difference.

I see this as a simple means to prolong engine life.

Originally Posted by tofu_box: My thoughts were just like a garden hose, if u let it open flow comes out less quite slack, but if u cover it with a finger the water will spray much more strongly, please correct me if i am wrong, that was just my thoughts.

Exactly wrong. The inlet of the garden hose sees an essentially constant pressure with a variable flow volume (regulated by the nozzle). The "inlet" of the engine oiling system sees a constant flow volume (assuming a closed bypass valve) at a given rpm, with the pressure being the variable.

The bypass valve is in parallel with the system, not in series, so it has no effect on the resistance to flow through the engine/cooler system.

Regardless of the details, Mazda apparently thought that doubling the relief valve pressure from ~70 to 150 psi to be worthwhile. In practical terms it means the Series II bypass never opens, so the oil system is running in a Flow = PumpDisplacement x rpm mode all the time.

Good info.

question for you HiFlite - a little off topic sorry .
in turbo charge pipes ---- if there was a restriction to flow causing an increase in pressure at that point , how far down the pipe would you see that same pressure ? Or would it instantly decrease past the restriction point ?

tofu box... your Oil Pressure gauge accurate??...you say it is..what grade of Oil are you using?


BTW, the Series II does not have a Rear by pass valve...

Air vs. oil = big difference. Air is compressable, oil not. I'm not the expert on this, but here's what I think. First, what kind of pressure? If one is talking about pressure measured on a gauge fitting basically at right angles to the air flow, that's static pressure, ie. the pressure the air has at a standstill or, here, pressing sideways on the walls of the pipe. The other kind is dynamic pressure is that felt by the "wind" of the flow. Mostly car people talk about the former. Given that, a restriction in an air pipe, or specifically, a change that decreases the cross-sectional area of the pipe, will cause a pressure drop at that point and beyond. It will only return to the original pressure when the cross-section of the pipe returns to the original size. That's not to say that the restriction doesn't cause a higher pressure upstream vs. no restriction (given a ~constant pumping of the air upstream), but at the restriction, the (static) pressure will drop, because the air velocity increases.

i am using 5w-40 semi s,

My cold start pressure is at 50-60 psi

Basically just subscribing to this thread as I put in a oil pressure and temp gauge today, and I may have a question........but that will be tomorrow after I check it out more thoroughly.

Car is NA and
First glance.......idle seems to be about 16-18 PSI.
Light load.......not really sure on the RPM's, but I saw between 50-65 PSI while just driving around the neighborhood.

Good one Dave! :)

Do one at 3000RPM and hot engine...what is the PSI?..
And what grade oil is in her??

Hey Mazsurf that is the exact numbers i see, 16-18 psi when idle.

Light load will hit close to 60 or so psi

load has no affect of oil pressure whatso ever. It is all rpm based.
You are getting pressures higher than the normal RX8. I have never seen a oem RX8 even with a 20w/50 oil get to 110psi after it is fully warmed?
You have a mutant car! Transformer prehaps?
rotor on
OD