2MCHPWR

hi -
my car uses about 1 quart per track day. Maybe a little more. I catch a lot of it in the catch cans. Most of it from the PVC line.

I have been using Mobil 1 5w-30. I have setrab oil cooler 625.
Temps usually in the 260's.

Is it advisable to switch to non-synthetic just to save some money?
If I should stay with synthetic, should I stay with 5w-30 or move to something thicker? If move to something thicker, advise on weight?

thanks!

John Shiels

Looking to save money on a qt of oil start waxing it instead of tracking it.

2MCHPWR

true but can regular dino oil withstand the heat as well as synthetic? i change almost half my oil in a weekend so if the dino is just as good, i would consider using dino oil.

geerookie

First, You should fix your PCV system so you quit sucking the oil out of the pan.

RE: Oils and Temps, In a word, No.

The following is a condensed version of my recollection of part of a conversation I had about oils with Bill Maxwell from Exxon/Mobil Engineering. He's one of the advisors that work with many racing teams one of which is the Corvette Racing team. He's been designing synthetic oils for longer than I've been alive. He used to live pretty close to me in NJ but I moved to a different town a few years ago.

The basestocks that synthetic oils are manufactured from have much higher flash points than petroleum oils typically do. The flash point of an oil is the point at which it begins to vaporize. The higher the flash point, the better the oil will hold up in high temperature environments. In addition, because synthetic oils are made up of molecules of uniform size, they have less "internal friction" than petroleum oils (which are made up of molecules varying greatly in size). This lowers the temperature of the oil, thus improving the cooling qualities of the oil. Of course, the end result is cooler engine temperatures.

Also, synthetic oils do not cause the "blanket effect" that petroleum oils do. Because petroleum oils are made up of molecules of varying sizes, the smaller molecules tend to flow freely through the center of the oil galleries within your engine while the larger sized molecules will be pushed to the "outside" of the oil stream - next to engine components. These large molecules, for the most part, remain there and do not absorb heat from engine components back into the oil very well as smaller molecules.

The uniform (and generally smaller) molecules within a synthetic oil will all flow just as easily through oil galleries. Larger molecules are not present to "blanket" engine component surfaces. Therefore, heat is absorbed into the oil and carried away more efficiently. (This is the primary purpose of oil)

The end result is that a good quality synthetic oil will lower engine temperatures.

Synthetics are recommended for today's engines because the tolerances are much tighter and they require the smaller, uniform sized molecules in order to keep the components cool enough to survive.

argonaut

Brad Penn Grade 1 High Performance Oil semi-synthetic is well respected in racing. Here is a write up about it: from Black Dog Racing.


That write-up and a few others convinced me to try it. It costs roughly $5.60 per quart online, so its a little cheaper than Amsoil or Red Line and the like. I've been running the 15w40 in my LS6 the last couple of oil changes. Here is the latest Blackstone report. The oil tested here had ~2000 miles on it. About 7.5 hours of track time + driving to/from events. Ignore the column from July 2009, that was from my old LS1 motor. With the exception of copper this seems fine (if anyone can interpret better than I can please speak up). Thus far people who have seen this have said the copper is likely coming from the valve train. Could that be oil related...? I have no idea but I think I'm going to have the heads rebuilt as preventive maintenance, they now have about 45 hours of track time on them. I should also mention that the car burns virtual no oil at the track.

Cobra4B

Amsoil XL 10w40 for me. Have thought about using the higher ZDDP 10w30 racing oils, but it ain't broke with 10w40 so I'm not going to fix it. The Amsoil XL is relatively cheap with the Amsoil preferred customer discount.

I actually catch very little oil in my PCV can... a table spoon per day or so. Typically I see the same amount in my fresh air feed line can (line from passenger side VC to TB), but this weekend at VIR I had the can about 1/2 full on Saturday. My thinking is that it being 105+ ambient caused more oil vapor to make it past the baffle and into that line.

My oil temp never got out of the 260s with my DRM kit w/ Setrab 625. Car uses about 1 quart per day on track, but it's a 2001 so it eats a bit regardless.

geerookie

Same here and the hi-temp sheer is better on the 10w-40.
The ZDDP numbers are so close it is irrelevant.
The XL 10w-40 is about 40% less in cost

VGLNTE1

If you are using that much oil, I bet your front plugs are soaked as well as the intake. The pcv set ups for these cars suck. You need a well baffled catch can. Hard to find to.
I run 0-40 Mobil.

Sidney004

http://www.youtube.com/watch?v=UQLkCz5z7Jk

2MCHPWR

hi - i run 2 catch cans and they catch a ton of oil but i think my plugs are good.
before the cans, i had tons of oil in the intake and mass air meter and air filter, dripping down through my bumper onto the ground.