for those who use 10w40!!!
 

read this...quite interesting!..

http://fc3spro.com/TECH/MODS/ENGINE/OIL/oilfaq.html

i've wondered what people think using SAE 50 weight. I've worried that might be alittle rough on the oil metering pump

I have asked before and a few people have said that using 10w40 is alright. I seriously have not seen or felt any difference between 10w30 and 10w40.

^ you wont ever see a difference either.

with 10-40 you will get a higher oil pressure, and less MPG, also the 10-40 doesn't lubricate as well as 10-30, being 10-40 is thicker and thus less oil is passed over surfaces as compared to 10-30.

Just change oil every 1000 miles with 10-30. You never get all the old oil out from the oil cooler, so change it often, to keep your oil injection lines clean and your engine.

I use 10w50

Works for me!

interesting. ive been using gtx 20w50 this whole time

So i guess 20/50 is way too heavy?

That was what was in it when I bought it... so should I change to 10/30?
Is 5/30 ok?

Follow what is specified in the owners manual

I put aside 2 gallons of Castrol GTX 10W40 for oil changes for my NA when I saw it on sale. Should I give it away and buy 10W30 instead?

From the article: "Very few manufactures recommend 10W-40 any more, and some threaten to void warranties if it is used. ... Follow your manufacturer's recommendations as to which weights are appropriate for your vehicle." Note that is says anymore as in for newer cars. I would also like to point out that most manufacturers are going to light weight oils while heavier weights are still recommended for our cars.

That is why I use 20w-50. If I lived somewhere cold in the winter I would go to 10w-30. There is a graph in your owners manual.

This is one of those threads that is going to turn ridiculous. A lot of people are not going to even read the article and a lot are not going to know what they are talking about.

Actually I have been saying for years, the same exact thing. 10W40 and 10W50 should not be used in modern High reving cars due to the additive packages used to get that viscosity spread.

If you look at the typical 10W40, in many cases it has considerable more left over ash than using a 10W30 or a 20W50, which can lead to deposits and fouling.

so thoughts on sae 50?

You will create unnessary wear everytime you start it up and continue to wear your parts until the oil gets to lubricate internals

Hasn't anyone ever heard of you build an engine with a certain clearance between bearings and surfaces, etc. Its called plastiguaging. You try to run 50w oil in an engine designed for 30w oil, the engine internals will be starved for lubrication during crital times, as you cannot get the same amount of 50w oil in the same passageway as 30w in the same amount of time given.

A worn out engine doesn't mean you should run heavier oil, you will ruin your engine before long.

I have had a RX7 with 450,000 original miles and ran a 14.7 with those miles. and never used anything but 10-30 in it for over 15 years.

10w50 synthetic is best IMO!

I have been using Valvoline Racing 20W50 but I only autocross and needed the better oil pressure as 20W40 was letting my oil pressure drop too far at the end of our runs. But after seeing that article I may move to Synthetic 20W50 rather than the racing oil. I am not too worried about ash content since we premix only.

What about 20w 40, diesel oil? I've used it before but i usually just follow the chart under my hood

Some people like diesel oil for the extra detergents. It's usable but it's not designed for gasoline engines.

Just get API 10w30 or 20w50. Other stuff is usually usable enough, but worse. So why bother with it? 10w30 is thinner, 20w50 is thicker.

The diesel oil i used said it was for diesel or gasoline engines. I used it for a while casue they always had 5 qt jugs in stock at the gas station by my house and my engine consumed it slower since i was going through a few quarts a week with bad oil control rings. I heard of a guy on here using 0w synthetic with a b2200 windsheild wiper tank feeding synthetic 2 stroke to the OMP. Sounded pretty cool, the tank even had a sensor for low fluid that the guy wired up so he wouldn't run out of oil

Straight 50 weight?

Not a chance in the world I would put that in my motor unless the temp never dropped under 120F out.

Banzai racing recommends 20w50 for summer driving. 10w40 iirc for winter.

yea i too have been using 10-40 for years on all 3 of my rotaries...never have i really noticed a difference....but next oil change i will move to 20-50...since summer is coming up...

castrol syntec has 10w50 i wann know what that goes in lol

The article is outdated. Modern polymers are much better now, and there is nothing wrong with 10W-40.

^ And the stuff they pump out of the ground is made of modern polymers? Do you mean synthetic 10w40? That has always needed less viscosity additives, but still some. Or do you need less modern polymers to make a non-synthetic into 10w40? No matter what you still need some, as the stuff they pump out of the ground doesn't change. And really I think you're just making stuff up. Though I never thought 10w40 was horrible, just worse.

To those who don't notice anything when using oil X:
1. There's not much to notice, and most oil that's less than ideal is still ok. People pay too much attention to oil.
2. Even with the horrible stuff - like SAE 50 - it takes time for it to wear away at your engine, and once the damage is done it's permanent. So you wouldn't notice a thing when switching.

10w30 is good from -5 to +85. 20w50 is good from 20 to anything. 10w40 has an even wider range. There's rarely a reason to switch summer and winter. That's why the oil viscosity on most modern oils has 2 numbers, it changes on demand to allow a very wide temperature range. That's also why SAE 50 (only 1 number) is only good under constant high temperature, as Icemark said.