if NYC never drops below 70 degrees I probably just gonna use straight 50 wt oil.

straight 90 is 90 grade oil

Are you joking? Oh, and doesn't straight grade oil increase temps?

no

does it look like Im joking ?

if my tempeature is always like 70-80s-90 or more I probably gonna just try and use 40 or 50wt oil all year long.

dont get me wrong 20w50 is perfectly fine, its just that I prefer less additives in the oil. thats all.

alright, this is going off topic. back to oil pressure. PRESSURE ! :lol:

You are getting confused.

1) Typical oil pumps are constant - volume which means the volume of oil they put out is directly proportional to how fast they are being spun; no exceptions.

2) Typical oil systems are regulated to a prescribed maximum pressure; in the case of the Series I that is around 70 psi.

3) Below the opening pressure of the bypass valve, the oil system is constant volume; within reason all oil weights will flow the same regardless of viscosity.

4) Below the opening pressure of the bypass valve, a heavier oil will give a higher pressure at a given rpm ('cause it's harder to push through the system), than a lighter oil, but the flow through the system will be the same.

5) At the rpm where the bypass opens and higher, the oil pump will remain constant volume (of course) but the oil system is not. With the bypass open, an increase of rpm will not cause any increase in the volume of oil being moved through the engine.

6) Since the bypass valve opens sooner with a heavier oil than a light oil, the volume of oil being flowed in this condition is *less* for a heavier oil than a light one.

7) Raising the opening pressure of the relief valve (as done with the Mazmart mod and on the Series II) causes the oil system to operate in a constant displacement mode: as the rpm increases, the flow increases, no exceptions (temp, oil viscosity, etc). Except for some slight leakage past the oil pump lobes, the system from the pump up to the leakage out of the bearings is in hydraulic lock. Comparisons with air systems are meaningless because air is compressable and oil is essentially not.

Note that under all cases, heavier oil will not get you more flow! (Though the pressure for a given rpm may be higher.)

Oh, I thought you meant that since the weather in NYC never dropped below 70F :lol:


^ Great clarification.

exactly--heavier viscosity will not increase the flow---but it will increase the film strenght---usually--- lol.

OD

shuutup OD !

What do u know about Rx-8 ! :dunno:

Mazda knows best ! 5w20 FTMFW ! :eek: :naughty:

Ah, not correct If you are referring to S2 RX-8...Engine Oil Pump does maintain Oil Pressure inside the two external EMOP's in the S2 up to 20 PSI.

ALL THIS CRAP HAS BEEN GONE OVER A THOUSAND F**KING TIMES BY THE SAME PERSON (s)..

To set the record Straight...Mazda made an Error with the S1 OIL Pressure (5W20) Market.....FACT...

ALL the S2 Mods to Oil Pump,EMOP's etc Increased OP, BUT all it has done is Return the Rotary back to where Oil Pressure SHOULD be, similar to the FD RX-7.

And I do not give a Stuff what anyone says, the Twin oil coolers with all that piping also Lowered Oil Pressure in S1's, what happened when Guys went to single or modded Single Oil Coolers, OP improved.

Yes, Mazda got it wrong with S1...Nothing NEW here...Dr Haas ;)

Or to put it another Way...

The S1 RX-8 was the First Rotary to Use separate TWIN Oil Coolers without any Real Mod to Oil Pump.
It uses the FC RX-7 Oil Pump..
FC Had a small Single Oil Cooler under Radiator.
The ONLY difference was Mazda changed the Oil Pump Pressure By Pass Spring in S1.

Was NOT enough, they should have used the larger capacity (cc) Oil Pump used in the FD RX-7, and the By Pass Valve in Rear of Engine...which is what this Mazmart mod is using..a FD RX-7 By Pass Valve with their name etched on it.

Agreed, but this stuff has to be re hashed so we don't forget :) Plus most of the threads that talk about this stuff are a billion pages long so most don't bother to read every single page and miss some important stuff.

Looks like it...Ground Hog day..:eek:

It really pays to understand the HISTORY first...;)

FC's as you know Jackson has an Oil Recommendation of 20W50...

USA RX-8's get the thin crap of 5W20, and BANG.. Lower Oil Pressure..

Just imagine how thin this muck is after 8000 miles with fuel wash, etc....

I repeat what I said 5 years ago....it would be like water..

Rotaries Do NOT like This Shit..period....Every engine re-man expert has said the same thing.

If everything else remains the same...increased pressure in the system will increase flow......can't help it..

Really what is happening is that the oil is forced to flow through the engine instead of out of the oil bypass..........

oh no ASH u are TOTaLLY WRONG.

come on ! according to X amount of "internet experts", what do u, me, and joe know! Mazda knows best ...

if Mazda tells us to use extra virgin olive oil ... thats the best and we all should follow.

Im just an ass and I always go diff route thats all :)

pm :)

got it You Tease!! ;)

I freaking wish, sad thing is the temps here can go as low as 15f to as high as107f

:wallbash:

This sentences are true!
It does not talk about oil viscosity numbers, so please Ash8 and nycgps, read it again, before joking on it! I think so.

How is this possible?

For example at 10 C a 20W-50 will flow the same as 0W-30 because the oil system is constant volume which is below the opening of bypass valve ?

It works because oil is incompressible. As long as the pump is strong enough it will maintain flow. Even when the bypass opens the pump is still increasing flow with RPM. The problem is that the bypass shunts most of the increased flow back to the oil pan. The stiffer spring rate of the MM mod simply raises the pressure where the bypass opens which increases oil flow to the engine.

hmm, I think I know all the information I need to know on oil & pressure related topics.

This is also the reason why I almost never made any post in this thread

I think you're one of the people who still don't get the whole idea :)

Peace

Yeah, some are true, under certain ideal conditions...

Simple, because as I mentioned previously the oil pump is a fixed displacement pump. It pumps a specific volume of oil for any given RPM. It does not matter how thick the fluid is going through it.

The description that HiFlite999 posted is right on the money.

Like I mentioned, Haas's article is a great read. His basic principles on fluid dynamics as well as the physics of oil systems are a good way to change your perception of how lubrication works.

The problem is all the information makes you run in circles over complicating the RX8 oil system, viscosity and general oil choice. The truth is that ANY oil in your engine is going to provide long life as long as fluids are maintained properly.

I'm 100% behind anyone who wants to make this an academic issue but I'd caution everyone about getting bent out of shape over it. Trust me, the life of your motor isn't going to hinge on it.

Just use Crisco oil like my neighbor did with his BMW.

Problem solved.

Not at all - the maximum pressure in a pipe happens when there is no flow whatsoever.