TrochoidMagic

tired of another oil thread???
it just seems tiresome and boring doesn't it?

but here's what i noticed all along and what i've stomped across:

Automotive Technology (2nd edition) by jack erjavec. pg 235, chapter 11.
lubricating and cooling systems.

table 11-2 SAE grades of motor oil
lowest atmospheric
temps expected
__________________________________________________ _____________

32F (0deg. C) single grade oils: 20,20w,30; multigrade oils 10w30,10w40,15w40,20w40,20w50

0F (-18C) single grade:10w; multigrade :5w30,10w30,10w40,15w40

-15F(-26C) single grade: 10w ; multigrade:10w30,10w40,5w30

below-15F(-26C) single grade: 5w* ; multigrade: *5w20,5w30

*SAE 5W AND 5W20 GRADE OILS ARE NOT RECOMMENDED FOR HIGH SPEED DRIVING.




thats the one thing i found.... and what does it say exactly on our oil cap? or any other manufacturers oil cap for that matter?
kinda conflicting isn't it huh?

and all along living here in cali, i knew i don't need a multi-grade crap oil. a straight 30w woulda been fine. but that seems like its the entry level grade oil allowable... i coulda been running 20w50 all this time or be at a 40w to be somewhere in the middle.

anyone here in cali care to do some sustained high speed driving? better swap out that 20weight bullcrap.



i still run somewhere in between though. but just thought i'd share with everyone in case if someone decides to buy some light weight oil racing oil, and wonders why their car overheats or have unacceptable amount of oil consumption.

thanks for reading... rotor on.

(sorry, had to edit. the table chart didn't come out right)

LionZoo

Watch out there! A straight weight might be good for racing, but on a street driven car, the extra start up wear from a straight weight being too thick would not be good for your motor. Also, look at the publication date of that book. It's 1995, which is 13 years ago. Motor oil technology has advanced and today's oil and engine tolerance controls probably are more favorable to thinner oils. Does that mean I'd run a 5W20? Considering the teardown reports from Paul, I wouldn't, and I don't. However, that doesn't mean I would avoid 5W20 in all applications; indeed I just switched my friend's Mazda 5 back to 5W20 from 5W30 as it seemed there was a bit more cold engine clatter with the 5W30.

Nubo

Careful, the date of that book is 1995.

ken-x8

Nobody needs crap oil, but you do need multi grade good oil. Unless you park your car in an oven, or have a heater in the pan to warm the oil before you start the engine.

Ken

05rex8

iTrader: (7)

so what's the best weight oil to use in a daily driven and daily redlined rx8?

nycgps

iTrader: (1)

Forget about my 0w30 pile, I'll save those for *lesser value cars like my bro's Altima **cough cough***.

Im going straight to 10w40 on my next oil change, ordering 10w40 soon, Full Synthetic of course, just trying to decide between RP(IV) or RL(V). Anybody with me ?

05rex8

iTrader: (7)

so....anyone?^^^

StealthTL

iTrader: (1)

i knew i don't need a multi-grade crap oil. a straight 30w woulda been fine

A little knowledge can be a dangerous thing......you just "knew it in your bones" that polyalphaolefins and polyolesters were never needed by your bearings, and some 30 weight paraffinic snot would do the job "just fine and dandy".

As previous posters have pointed out, that book is DECADES out of date - in fact it is the original edition with the chapter on carburetors edited out, to make it look relevant.

Back in the day (which was, according to Dane Cook, a Wednesday) fine synthetics like Mobil1 5w50 didn't exist, partly because making them was virtually impossible, given their level of technology.

....and as for overheating - thinner oil will ALWAYS cool better than snot - just Physics 101.

S

Eight

iTrader: (2)

I'm with ya, thinking of going redline next oil change , probrably 5w30s or 40s...

Rootski

iTrader: (1)

I'm rocking 10w30 now.

nycgps

iTrader: (1)

We can always try Canola based oil ya know

I think its gonna make our 8 smells like corn the whole time

Im still debating which brand to buy, RP or RL, 10w40 most likely.

TrochoidMagic

pardon my physics101 and my lack of awareness to the book's publication date.

understood the valid cases some are presenting...but please don't be a wise *** about it. so who the hell told anyone any blah blah additive was good for blah blah metals and such? did you talk back to ur teacher.... i hope not.

so kill me if i use a multi-grade for winter and plan to find a straight grade or a thicker multi-grade for summer.

TrochoidMagic

ok. thanks bud. nice to know thin oil cools better than SNot.

i guess i will thin out more oil so i can have a cooler engine...

will water work, and will i sacrifice any lubrication qualities in the process?

swoope

iTrader: (5)

wait,

your read just enough to post stuff 12 years old. but missed all of the info is here. not as easy to find. but is aimed right at the rx8.

your point is?

btw, stealth is the last person whos buttons i would try to push..

beers

rotarygod

FWIW: I break in new rotaries with straight 30W conventional for the first 1000 miles. It gets changed 3 times in that mileage span. After 1000 miles I switch. Older rotaries always ran 20W50 and of course I use synthetic. I've used all different oil weights including 5W20 in older rotaries. For me it all comes back to 30W oils (5W30, 10W30, etc) as a minimum. Keep in mind I live in Houston so remember what my cold weather is like. It gets plenty hot here. For older rotaries I like the thicker oils. The Renesis doesn't seem to like it quite as thick but that's not to say 20W oils are best. If you aren't sure, default at something around a 30W type of oil. Thinner has proven not be be good in the longterm.

nycgps

iTrader: (1)

I have a feeling I will see something like the following again :

*Do you think Mazda will recommend something that is going to compromised their flagship car ?*
*Mazda knows best of their engines, 5w20 will work just fine!*
*Thousands of of 8 owners use stock 5w20 and is working fine!*

blah.

1. Yes, as long as it works for the warranty period. To the general public, any car thats over the warranty period will consider as *user's own freaking problem*. so as long as they can keep it running under warranty period, thats all it matters.
2. They do know their engine of course, answer same as above.
3. Yep, also thousand of owners never bother to open their engine to find out the root cause, instead they will just tell the others that "Rotary suck"

Nubo

And it's even funnier because RX-8 is ANYTHING but their flagship car. When is the last time anyone saw a TV ad for RX-8? Print ad? The dealers hate it.

nycgps

iTrader: (1)

hmm, it is still their flagship car. but Rotary engine has such bad name in the US, so bad that MNAO actually afraid of telling ppl in the public.

Those who actually buy Rx-8 either came from older rotary community, ppl who knows nothing about automobile history(including rotary engine history), or ppl who just like the *looks* and never cared about what engine it has.

Mazda use Rotary engine to "tell" the world what kind of things they can do

XRX8X

it's like a steak..most people like it but not everyone buys it.even when it taste great people nowadays are to lazy to enjoy the little things anymore that take time to chew or whatever!the rx8 is like a relationship you start and love but don't want to give up because of other peoples thoughts and personal taste.nuff said.