Mazmart

iTrader: (12)

I need to make a minor correction to my last statement (Which was improperly phrased) as the low viscosity is not encouraging more shear but of course shear can and will affect the viscosity.

Paul.

ASH8

Hang on Phillip...you live in the UK mate...
You guys think 26c (80F) is a Heatwave....
Live and use a car where it gets to 40- 45c, average 36 in summer with a 30 weight...no thanks..

PhillipM

Yes, but the difference is, I'm at full throttle for 60% of the cars run time, and it never drops below ~5krpm, my engine is panelled in a lot tighter than yours, my exhaust wraps all the way around the engine on all 4 sides just a few inches from it simply due to space constraints, and as it's rear mounted there's not much airflow over it - in fact, what there is comes straight through both the radiator and oil coolers in the main, and the little extra airflow that doesn't come through the radiators comes past the damper reservoirs to cool those before hitting the engine....

I think we probably have more heat in the bay than you do...

PhillipM

Yes, if you had all the supporting mods - single cooler, better water temp control, more pressure, complete flushes during an oil change, pre-mix, etc, and put a top quality synthetic in there and changed it every 5-8k miles, then perhaps a 20w would do the job just fine for the average user (which probably rules out everyone on here...)
However, once they start to drop below the 20w they started at, that's when you're running into problems with the film strength of the oil, it must be borderline at 20w with average oils, but a cheap 30w oil could drop to the upper 20w class if left in there a while anyway, so certainly a decent 30w, or a cheaper 40w is what wants to go in there, along with a few tweaks.

olddragger

iTrader: (3)

the 30W's I have seen tested --so far will sheer down to a 20 W in a couple thousand miles.

IT HAS BEEN RAINING ALL DAY--TEMPS 40F--WIND CHILL IN THE HIGH 30'S. I DO NOT HAVE A GARAGE. .......BUT THE KIT IS INSTALLED. AN EZ UP AND LONGJOHNS HELP.
PICS ARE TAKEN.

I will report findings tomorrow.
OD

ASH8

Can you put some pics up (or link) to show us...please???

ASH8

Wow..Denny take it easy (old man ), I guess it is going to be difficult to get your Oil temps up to a Max operating temp?..

BTW..What happened to your Avatar...cap'tin

Spirograph

ditto

olddragger

iTrader: (3)

kit install and here are the results---im smiling.
to define kit:
1-Mazmarts modified rear bypass and shims x 2 on the front bypass
2-09 oil filter
3 15w/40 Valvoline blue diesel oil.

its an easy driveway install (if it had not been for the cold rainy weather here.)
you will need a 26 mm short socket to remove the rear by pass and a 24 mm for the front.
3 pieces of homemade carrot cake and 1 beer.
other obvious stuff--towels , gasket maker etc
remember to check the oil pan(or sump pan) bolts for dried gasket material on the ends.

RESULTS:
ON COLD START --110 PSI OIL PRESSURE GAUGED PEGGED.
OIL TEMPS @ 170F
IDLE (1100K FOR ME)-------38PSI (WAS 30 BEFORE)
2K----------------------------48PSI
3K-----------------------------70 PSI
4K-----------------------------96 PSI.

OEM
cold start --------------------80psi
after warm up same temps as above
1- idle .....................30psi
2- 3K........................63psi
4K.............................72psi

Thats as far as I took it today--dont need anymore figures as this kit has demonstrated that it will substantially increase oil pressure and therefore it will increase the oil flow (theoretically at least)

happy olddragger
on cold start up it pegged to 110psi

madcows

Denny, for comparison sake, what was your OP in those ranges prior to the bypass mods?

madcows

OD, I know you mentioned stress on the front e-shaft bearing from a supercharger/belt/pulley recently, and while I'm pretty sure you've already seen the following, I'll post it anyways just in case, or for some other people on here that may have not.

Racing Beat has all sorts of tech articles on their website discussing much of what we have been talking about here. Here's an excerpt from one:


"A weak point of all eccentric shafts is the tendency for the front shaft extension to bend adjacent to the front main bearing journal. This distortion is usually caused by high RPM or some excessive force on the front pulley. (For this reason, caution must be exercised when installing a belt driven supercharger to avoid this distortion.) We suggest both of the following two techniques to minimize this bending problem:

First, increase the torque on the front pulley from the factory specification of 72-87 foot-pounds to about 120 foot-pounds. In doing so, there is a tendency to crush some parts and reduce end play. Do not allow the end play to get below .0015-inch. If necessary, change to a thicker end-play spacer. The stock needle roller thrust bearings have proven to perform satisfactorily with this adjustment.

A second technique to minimize bending is to upgrade the thrust bearings to the type used in the 1992-95 RX-7 and RX-8. These thrust bearings are larger in diameter to better resist the bending load."

madcows

And just one more:

"Supercharging/Turbo Recommendations:

1. Increase oil pressure to approximately 80-90 psi, or to 120 psi or more if the engine is bridge-ported or peripherally ported (we use 150 to 160 psi in the 900 HP 3-rotor engine)."

PhillipM

I haven't got a recent one with the proper radiators/oil coolers/enclosures, etc, in, thi is from when we were mocking the fittings up - but you can see what I mean by the exhaust here:



I'll get a decent picture this week for you.

madcows

What the F*@K is that thing?!!?

olddragger

iTrader: (3)

baja type rig--judging by the length of the shocks.
thanks for the tech RB articles--yep we know.

I didnt mentioned that my home was burglarized Friday --all my TV's 52 inch lcd and a 36 lcd and a new ps 3--all gone +they crowbarred my rear door.
Kinda broke Christmas for the family.
Glad i had this project--it was therapy of sorts.
OD

PhillipM

AS Oldragger says, it's an off-road Safari car.

Flashwing

Phillip's statements, as usual, are right on the money here. One of the primary reasons that high RPM engines need a lower viscosity oil than a motor with a lower RPM band is due to the fact that thicker viscosity oils will shear much quicker and easier in higher RPM applications. Not a problem for race engines but a serious problem for street driven vehicles.

From a race engine perspective, it's not that the thicker viscosity was providing any extra protection but that it but it's not left in the motor long enough to have any negative effects. Well, other than reducing engine efficiency. So, if you're running a thick 50w viscosity oil you can expect quite a lot of shearing and the problem would be worse with mineral oil since Viscosity Index Improvers are the first stuff to go.

Another serious difference between race engines and street cars is the operational RPM range and how it relates to oil barrier films. When you're operating at a higher RPM range you're able to easy maintain a hydrodynamic wedge in the bearing and thus maintain a hydrodynamic barrier. The primary areas you see that barrier fail are lower RPM, higher load situations.

Regarding particle suspension in thinner oils: Then the problem isn't so much the viscosity of the oil but the length of time it's been left in the motor. If you're having excessive particle suspension you'll be able to detect that with testing and obviously adjust your change intervals.

If the lack of barrier film is viscosity related then increasing pressure isn't going to do anything to combat that. Pressure will only solve issues if the problem is getting oil into the bearing. Once you have enough pressure to get oil into the bearing anything extra is just that.



Since pictures are worth 1000 words I've included the stribeck curve for anyone who still thinks this stuff is nonsense. Understand what this graph means and you'll understand why I've been saying that aiming for that middle range is the best idea.

olddragger

iTrader: (3)

if anyone noticed--the by pass mod did affect the pressures through the lower rpm range--not just at the higher rpm range, Does this say that the bypass was open much more than originally thought?
If my logic is sound i was bypassing a lot of oil.
olddragger

ASH8

While I do not doubt your information Flash..thanks..

One should also surely consider 'how' they use their RX-8 and at what RPM levels their engine runs at, frankly for "normal" use RPM above 6000 RPM is abnormal...unless you are on a track.

Most rotaries and owners driving their cars would see RPM ranges between 2800 and 4500, anything more here where I live and you are unfortunately breaking speed limits...and will soon lose your drivers license very quickly.

Naturally, I am not talking gear change RPM peaks/loads but "cruising" RPM / Speed.

While I appreciate Phillip's input, this is an RX-8 forum and comparing an Off Road'er or Baja modified to the max will show interesting numbers but does not really relate to the daily use of a road certified car...like the RX-8 or the standard OEM parts....

Assuming Phillip all your posts are about an "off-road Safari car"..?

I just don't wont some members to be "confused" (for the want of a word) between the two vehicles...and their differing statistics.

Flashwing

That's why I believe it's very important to show the major differences between race motors and street driven motors. Up until now, the majority of positive proof that higher viscosity oils protect motors has been established using race motors. Clearly, the difference in operation and application is the primary factor which means that you cannot apply what works in racing situations and assume it will work for the street as well.

It appears from my research that the more the engine is operated in the higher RPM band that lubrication (provided the temps stay in control) isn't a problem. Since, as you pointed out Ash, people operate their RX8 in the lower RPM band on street cars then we have to examine it from that standpoint. Substituting RX8 data from vehicles that operate in totally different areas won't wash.

ASH8

Up until the RX-8 (RENESIS) at this side of planet earth all engine Oil Viscosities for ALL rotaries was at the Higher end of the scale..

In Australia...Distribution recommendation..
FE RX-8 5W30
FD RX-7 15W40
FC RX-7 20W50
ALL others 20W50

madcows

I thought about it for a little bit.. If there was plenty of capacity from the pump left over (and exploited by said mods), then why did mazda need to increase the capacity of the pump for the S2? I wonder what kind of OP we would see if you were using 5W20 instead - which may just be why capacity needed to be increased.

And at any rate, can there be any downside to this mod other than extra strain on the pump?

ASH8

How many times have I said this...partly to do with the new two EMOP's, keeping a constant Oil Pressure inside them, also for cleaning mode of the pumps and nozzles and tubing and also to increase internal engine operational OP.

From 09 Service Highlights...
OIL PRESSURE CONTROL OUTLINE [13B-MSP]

�� The amount of oil supplied to the metering oil pump is adjusted based on the engine operation conditions to
keep the oil pressure inside the metering oil pump constant.
�� Based on the input signals from the oil pressure sensor, the PCM drives the OCV and switches the oil
passages of the metering oil pump so that the oil pressure inside the metering oil pump is kept constant.

PhillipM

Mke your mind up ASH, you've just told me that we don't get the engine hot enough for the data to be relevant...

ayrton012

You modded all of the two regulators in the same time, so we don't know the answer.
Anyway I think the front regulator's spring is our problem, because the max oil pressure is about 73 PSI (non modded cooling system), no matter that the oil is cold or warm. It is lower than the rear bypass opening pressure. We would have to reach higher pressure at least when the oil cold, if the rear valve has effect on it.