Icemark

Not just brand, but formulation as well.

For example, Castrol conventional oil is great for low additives and ash content. But their synthetic and synthetic blend is crap and full of all sorts of undesirables (much like almost every Valvoline Synthetic and synth blend I have seen).

and it also varies based on formulation, for example AMSOIL can formulate their 10W-30 and 15W-40 with no viscosity index improvers but uses some in the 10W-40 and 5W-30.

Icemark

Well that doesn't follow any logical conclusion, unless you are just trying to bash the use the 20W50. From a purely logical stand point, only 46% of the engines blown would have 20W50 in them.

Yes I think it would be also intresting to see, with the almost 25% of responses in the poll being 10W30 and more than 12% being 10W40, while 10W40 shouldn't even be used in a modern engine (IMO).

However, I think you would find very few people that would admit that they had an engine failure because they were lame and put the wrong weight oil in. It would be more the "I blew a seal, I must have boosted too much" or "I advanced the timeing to get 2 extra HP out of my NA and fried the motor, while racing this Honda".

Instead of the "gee, my engine wore out because I used ________ (insert oil weight) and only changed it once every 6 months."

pmr2000

Now you guys got me worried, I've been using 10w-40 for 15 years! Would'nt 5w-30 have the same issues as 10w-40? Most new cars are recommending 5w-30, is it for fuel and emissions savings? Seems like 5w-30 would not be good enough for summer, unless all the new oils are so much better.

Icemark

Yes, 5W30 has the similar issues that 10W40 and 10W50 have. You don't find any conventional 5W30 in my personal cars.

The reason that 5W30 is recommended more in modern engines is that there are considerably tighter tolerances of the moving parts, than engines built 10 years ago. Modern engines could use 20W50, but the thickness of the shear surface would be increased, which coupled with tight tolerances of the moving parts would reduce HP and increase emissions.

tmiked

I cant believe it is the twentyfirst century and we are seeing all these 'the world is flat' posts in this thread. Just cuz your friends, sister's grandaddy tole you about blowing up his engine doesnt make it relaative today.

1) New cars recommend 5W-30 to give a TINY increase in gas mileage in the EPA tests. The increase is miniscule but every little bit helps them get to sell more overweight POS's. It has nothing to do with tolerances or any other of that BS.

2) Single weight oils e.g. 30W, are history and any advantage of 'having less additives' or ' working better under high temperature racing conditions' went away the same time eight track tape decks did.

2) Mazda many years ago recommended not using syn oil because of some ash buildup problems in testing. This has been corrected and is now old history. (See the Mobil-1 site for instance).

3) For every rotary engine blown for an oil related reason, 100 have been blown from running lean or too much boost. The most common oil related reason would be lack of warm up before revving. Synthetics help prevent this by staying coated on moving surfaces better while the engine is off.

4) Synthetics are better than conventional oils in ALL respects and will easily pay for themselves in increased engine life whether they make more HP or not.

4) All this stuff about one brand being better than the other is BS. The oils all come out of the same hole in the ground. The companies all use the best additives they can afford and if one company develops a beter one the other copies it immediately. They are always hiring away each others chemists anyway.

5) I use Mobil 15-50 because I drive my car hard and it is hot here.

6) In my other car (2002 M3) I have to use Castrol 10W-60 ! to keep the warranty. I am considering this for my RX-7 as it would be GREAT protection but $ 10.00 a quart is a little hard to take.

Steel

Im kind of suprised at the lack of discussion about the (second?) most important part... the oil filter.

I cant remember where... i think it was FC3spro.com, did an oil filter comparison, and found the mazda filter to be one of the best, despite it's small size, (Afterall, its not the size of the dog in the fight, its the size of the fight in the dog, right?). And that Fram is a cheap orange POS. But everyone knew that.

So who uses what sort of oil filter in their car? I personally use the mazda filter. Costs just as much as the mobil 1 filter, and IIRC does a bit better job.

Synchro22

I heard the same thing about the oil filter. But the big argument in that one had to do with the Plastic valve VS the Metal Valve found in the top of the filter. If I remember correctly it was on the teamfc3s.org mailing list a looooonnnggg time ago. I could be wrong though.

deadRX7Conv

Looking at a filter tells nothing about the filtration media, performance, flow, restrictions, capacity.......
Don't judge a book by its cover. There aren't too many people qualified enough to look at a media type and can make a call on whether it works or doesn't.

The oil filter isn't as important as most people think. With frequent changes, some claim that it is a worthless appendage. I myself believe that it is needed but seriously overated. I'll stick with 2k change intervals and grab almost any filter that is on sale now.

Concerning the orange canisters, you won't find a PH# under my hood but there aren't any reported engine deaths only because of the filter. You won't find pretty metallic blue PL# filters either. This is from personal experience. Certain high end filters are overly restrictive. Certain lower end filters have so-so ADBV performance in cold weather. Neither was noticeable in the rotary, but were very noticeable in boingers with noisy valvetrain...

The Mazda filter is the best for the money.
Other brand filters must meet or exceed its performance in order to prevent warranty issues.

I am currently holding and using various oversized filters for additional filter capacity, oil capacity, media area, less restriction....
If anyone wants to know what PN is oversized, list your filter brand/part number and I'll list the same brand with a larger canister # if available in that brand.

abarlas

castrol 20w-50 in the summer, 10w-30 in the winter

ilike2eatricers

castrol 20w50

on a side note my friend mentioned that castrol was bought by another company... any truth in that?

Driv300mph

FlyBy116 had told me to use 10w30, however he lives in New Jersey...

Judging by the weather factor, with me being in Oklahoma, should I just run it with 20w50 year round?

SonicRaT

iTrader: (6)

I'm running 20w50 in my lovely -20 degree winter weather here in michigan

DEZERTE

20-50 alwayz

steviep_

20w50 in my baby

RX7-RICE EATER

Castrol GTX 10w30

boosted1205

iTrader: (9)

Damn! This thread revived from the dead! Here's some reading on all you **** oil freaks like me


http://www.xs11.com/stories/mcnoil94.htm



http://www.vtr.org/maintain/oil-overview.html

Driv300mph

Guys, I'm not really familiar with the climate in New Jersey (Where my car came from) but it's now in Oklahoma, should I use 10w30 or 20w50?? I'm leaning towards the 20w50, but it get's pretty damn cold here too... should I just alternate? Thanks!

Mint87RX7

I havent read the entire thread so i hope this hasnt already been answered but in the first 2 pages you talked about flooding, gas gets into the oil so it has to be changed. how does the gas get into the oil, just a little confused.

boosted1205

iTrader: (9)

20W50 is much thicker than 10W30. It's not recommended when temp dips to certain degrees.
A 20W50 gets too thick in cold climates and will take longer to warm up.
Look at the site I attached. Look at the pour points.
Most common oils are there. I'm using Redline 20W50 (no OMP) since it's always warm here and *no*ash content / very low pour pont.
This site should be a Bible to all you grease monkeys and ones who care about their engines. Castol GTX 20W50 was one I used to use.

Driv300mph

What link bro?

boosted1205

iTrader: (9)

This one

Driv300mph

Sweet thanks... what exactly is a Pour point?

boosted1205

iTrader: (9)

Read the lower site. It explains everything you want to know about oil.

Driv300mph

Double post

Driv300mph

Ok I think I'm going to go with the Red Line 20w-50 since it doesn't get too cold down here, maybe 20 degrees or so.

The 20w-50 is better in hot weather though correct? And if I'm not mistaken, with a -49 pour point, it shouldn't be bad in 20degree weather right?

How much does the Red Line 20w-50 run per qt.? Thanks...

Driv300