[Wolverine 250R]

I'll be going to the track for 2 days this weekend at Watkins Glen. I currently run Mobil 1 5w30. (about 1500mi on what is in it now).I am concerned that this may be too thin for the track. The weather is going to be a high of 60F and a low of 38F. I usually burn about 1qt every 3000 miles. Searching on here, I've heard 10w30 or 10w40. What do you guys reccommend?

Thanks,
Scott

[Shamoo]

I'd go with what the manual says, and what Subaru recommends which is 5W30. Our engines were built specifically for that weight oil and anything thicker could damage something internally. Sounds like you need an AOS burning that much oil.. just my opinion.

-shamy.

[Ikon]

15w40 track only.....thats what i use. most go with the 10w40


shamy- Our car wants 5w30 but hes tracking his car and 5w30 is like water.

[Wolverine 250R]

Thanks for the help, so mobil1 15w40 then? Looks like I can pick that up locally, then swap it out after this weekend. Will it be ok to drive ~200 miles on the street with 15w40 in it?

[ACHAHockey]

You'll be good on the street.

Good luck, I was planning on going this weekend since Saturday is my birthday, but, other things came up.

[Thejoyofdriving]

"As we increase the heat from 212 F to 302 F the most commonly recommended oil (0W 30 or 10W-30)thins from 10 cS to 3 cS. The thicker oil drops from 20 cS to 4 cS. Note that in a very hot engine the difference between the two oils is now only 1 - 2 cS. In other words they have about the same thickness. There is little advantage to a thicker based oil as a 20W-50 at very high temperatures. No, the 4 cS oil is not twice as thick as the 2 or 3 cS oil. This difference is almost insignificant."- Oil expert.

So it appears that using at thicker oil at race temps is not really all that much of an advantage.
Since 80% of wear happens at start up, you want to start with as thin of a oil as possible.
http://www.iwsti.com/forums/engine-p...ichat-com.html

"It is time to dispel the notion that 0W-30 oil is too thin when our manual calls for 10W-30. A 0W-30 is always the better choice, always. The 0W-30 is not thinner. It is the same thickness as the 10W-30 at operating temperatures. The difference is when you turn your engine off for the night. Both oils thicken over the evening and night. They both had a thickness, a viscosity of 10 when you got home and turned your engine off. That was the perfect thickness for engine operation."

So 0W-XX is better.


This is all according to "Dr. Haas is a physician and surgeon. He graduated from the University of Florida with a degree in biochemistry with honors. He studied motor oils since high school where he did independent studies on this topic. He studied the properties of viscosity.

When he was a general surgery resident in Chapel Hill he studied the flow mechanics of human blood. Today he continues his research by discussion of oil products with chemists in the field and chemists from the oil manufacturers.

He has personal racing experience in Formula Super Vee. He is his own Lamborghini and Ferrari as well as Mercedes mechanic.

"


I ve read all 8 chapters and am more confused than ever. Honestly if this guy didnt have the credentials to back his stuff up i would wonder what he was smoking......

[Shamoo]

Originally Posted by Ikon

15w40 track only.....thats what i use. most go with the 10w40


shamy- Our car wants 5w30 but hes tracking his car and 5w30 is like water.

With the clearances in our engines, "water" is the only thing that will fit between internal components and bearings. Go to thick and *boom*.

..Yet another possibility of the blown engine threads I've found. Hmmm.

[Tgui]

Originally Posted by Shamoo

With the clearances in our engines, "water" is the only thing that will fit between internal components and bearings. Go to thick and *boom*.

..Yet another possibility of the blown engine threads I've found. Hmmm.

10w40 is perfect for hot track days. Your engine tolerances aren't as tight as you think.

Every person I know that tracks their car uses 10w40 in fact. You haven't found anything...

[Shamoo]

Originally Posted by Tgui

10w40 is perfect for hot track days. Your engine tolerances aren't as tight as you think.

Every person I know that tracks their car uses 10w40 in fact. You haven't found anything...

Might as well throw some Motul 75w90 in there then..

[Tgui]

Originally Posted by Shamoo

Might as well throw some Motul 75w90 in there then..

Wow, great info. Post after 3 years of high speed track days in 100+ degree weather in your STi.

[flatthump]

Originally Posted by Shamoo

Might as well throw some Motul 75w90 in there then..

Dude you're trippin.

Motor failures due to thick oil? You don't think a 40W oil can fit between bearings? I'm sorry, but that's hilarious.

On really hot track days, I run a straight 50W. Normally I run Motul 5-40.

[Shamoo]

Originally Posted by Tgui

Wow, great info. Post after 3 years of high speed track days in 100+ degree weather in your STi.

http://www.iwsti.com/forums/engine-p...ichat-com.html

Maybe you should read this a couple times..

10w30 and 0w30 are the exact same thickness at operating temperature.

But since you want to run 10w30, when you shut the car off and it cools down, the oil will be too thick for what the engine was built and designed for.

[Shamoo]

Originally Posted by flatthump

Dude you're trippin.

Motor failures due to thick oil? You don't think a 40W oil can fit between bearings? I'm sorry, but that's hilarious.

On really hot track days, I run a straight 50W. Normally I run Motul 5-40.

You do know that 50w is only when it's cold right? As soon as it warms up it's the same as 0w30, 5w30, 10w30, etc. You should read the above post also. Thanks.

[Tgui]

Originally Posted by Shamoo

http://www.iwsti.com/forums/engine-p...ichat-com.html

Maybe you should read this a couple times..

10w30 and 0w30 are the exact same thickness at operating temperature.

But since you want to run 10w30, when you shut the car off and it cools down, the oil will be too thick for what the engine was built and designed for.

First off, I stated 10w "40"

Secondly, I read that thread a long time ago. Difference between you and I is that I can comprehend whats being discussed.

Finally, I speak from experience, both from being on the track and also education wise since one of my engineering degrees is in Mechanical Engineering. Lets say I have just a wee bit of knowledge when it comes to fluids.

Go home kiddo.

[flatthump]

Originally Posted by Shamoo

You do know that 50w is only when it's cold right? As soon as it warms up it's the same as 0w30, 5w30, 10w30, etc. You should read the above post also. Thanks.

You think you're about to school me on oil? Go right ahead.

When someone says: "I run a straight 50 weight" or something similar, they mean they run an SAE 50 with a 0w cold temp rating.

I don't know if you've ever been to the track, but after several miles of track driving, the oil gets so hot that pressure actually drops quite a bit. I have never run anything less than 40 weight at the track and my pressure will go all the way down to about 4.8 Bar from 6.1Bar. I can't even imagine if I had a 30 weight oil in there.

The 50 weight keeps the pressure up around 5.5 bar for my whole track session.