Best oil in texas

i know they say to run shellhelix but before i bought my ferrari, everything i owned had mobile 1 synthetic. I dont want to blow up my engine, but would it be better to run 5w 40, 5w 30, 10w 30? is shellhelix required for some specific reason? What do you guys in the south usually run?

 

Redline 5W40 in my 348.

 

Mobil One 10W40 in mine

 

The stock answer is stick to the factory recommended oil--typically 10W-40. But since its a Ferrari, feed it a good Synthetic oil. The Ferrari Recommended oil has a cold start viscosity of 84cSt an operating viscosity of 14cSt and an HTHS of at least 4.2cP. So, what this basically means is that the oil chosen by Ferrari will allow you to use the engine up until the point where it is no longer lubricating like an oil with 4.2cP of viscosity. This means that wear does not accelerate to unacceptable levels, by road car standards, until the oil is thinner than this. By the point that typical operating viscosities are in play, virtually no wear is taking place on lubricated components.

The first thing to realize is that a large part of the additive package does not work until the oil gets above 150dF. So the acids are not being neutralized and the ZDDP is not producting sacrificial oganic films on the metal surfaces. So do not be hard on the engine until it gets up to temperature. After it gets up to temperature, run the living snot out of it.

The second thing to remember is that oil lubricates by preventing metal to metal contact. The price the oil pays is that it absorbs significant energy in holding these things apart. This makes the oil hot. Hot oil thins out, Thin oil does not hold the metal parts apart. Bad things happen. Note the culpret is heat not the thickness of the oil.

Scientists measure the thickness of an oil either by the Stoke scale or by the Poise scale. The Stokes scale is pertinate to all kinds of lubrication from journal bearings, to sliding friction, this is where wear is being prevented. The Poise scale is used when journal bearings are in use at the edge of their design range. Oil passing over a journal bearings absorbs significant heat and then is thrown off the bearings. The velocity of the thrown oil is dependent on the density of the liquid, and thus the difference between the scales is this density factor. Since oil is close to a density of 0.9 to a very first order which scale does not mater for engine oils.

As the oil is squeezed preventing metal to metal contact, it flows towards regions of lesser pressure. Thus something must be used to push new oil in to prevent wear on the next cycle. Here is where oil pump pressure comes in. The oil pressure only has to be sufficient to push new oil in behind the heated oil just leaving the bearing. More pressure than required wastes power, and is often simply diverted back into the oil pan.

It is the viscosity of the oil that prevents metal to metal contact. And you engine wants this viscosity to be 10-12 cSt at operating temperature. All the clearances and tollerances are based on an oil in this range. And it ends up that 10W-40 oil is to thick when you are cruising down the interstate at 70 MPH with an oil temp gauge reading 185dF. You oil will be closer to 18cSt, with oil pressure pegged at the pop-off valve pressure setting. For this kind of setting a 0W-30 oil is actually the better oil, especially those with an HTHS number above 3.8. However, drop off the interstate and start straifing apexes, and the oil temperature rises into the 230dF range. Now the engine is at its ideal operating temperature. The water will be 212dF and the oil only slightly hotter. The oil is now at 10-11 cSt and the engine is as alive as it will ever be. Nothing is too hot, too thick, or too thin. Running the proverbial snot out of the engine in these conditions creates very little wear. Its when the water temp gets to 225dF and the oil is above 285dF that wear becomes significant. Wear remains tollerable up to 300dF which is the factory setting for telling you to cool it.

If you start in cold weather, the important number is the cold viscosity (measured at a fairly high 40dF) you shuld be looking for an oil when this number is 80cSt or lower. This is where 15W-50 and 20W-50 oils are simply too thick. The thinner 10W-40 oils are just fine here, the thicker ones are not so far out of the desired spec as to mater much. If you don't get many miles in per trip in these conditions, a thinner oil such as 0W-30 will reduce startup wear. As long as the oil temperature gauge stays below 260 there is nothing to wory about, but DO worry if the gauge gets above 285dF as the shut-it-off-before-you-hurt-it oil temperature.

If you are using an heavy oil and the engine is cold two "interesting" thing may happen. You will not like either one. First, the oil may vacate a bearing faster than new oil can be pumped in. This leads to high wear on the loaded bearings until the oil thins out enough for the oil pump enough oil back in. Second, if a large cylinder pressure develops (throttle applicaton), the oil in the crank throw may see sufficient force to cease being a liquid. It will end up with a viscosity higher than that of the bearing material, and a galled or spun bearing can ensue.

If you never see oil temperatures above 260dF and are willing to either slow down or change the oil back if temperatures above 285dF are seen, you can use oil as thin as 0W-30 with an HTHS of 3.8. It is even good for race track use in the midst of Texas summers--barely, and only with an eye on the oil temperature gauge.

If you change your oil after every track weekend, you can use race oils. These things have less detergents, dispersants, a heartier additive package, and more base stock. They are not, however, magic wear reducing agents, just an ameliorant.

If, on the other hand, you have a garage queen (and be honest with yourself), look for an oil high in detergents and with a high base number to neutralize acids.

If you take your car to the race track, you should be looking for an HTHS number above 4.2. This number represents the oils ability to prevent wear at high temperatures (like 300dF).

If you see continuous oil temperatures above 285dF you should consider one step heavier weight oil such as a 15W-50 or 20W-50 oil. However, note, even in the midst of Texas summers, at Texas race tracks I seldom get to 285dF oil temperatures in my F355. The real fix, here, is more (clean) oil radiator surface area to keep the oil temps down.

If you exced any of the aobve temperatures by more than 15dF you will have gone from the region that wear is not as low into the region where wear is accelerating rapidly.

Notice that the entire discussion is almost devoid of xxW-yy numerology. You see, oil is not as described by those numbers, it is described by Stoke and Poise numbers, alternate properties are described by HTHS, Base Number, and alike. So, when you buy oil, look it up online and read the data sheet looking for these numbers. Then factor in how you are going to use the vechcle, and choose an oil for the cross product of those uses and that vehicle.

 

Mate, you surely know your oils !

 

Well someone is giving Ali a run for his money.



Nice post Mitch.

 

I really want to read Mitch's post again tomorrow when I'm coherent.

 

Lol...Mitch, that is one hell of a write-up

 

Mitch,

Fabulous write up (as ever) on oils and I made the effort to follow the logic. Since I freely and without embarrassment consider my 355 to be a garage queen, could you specify a make and grade of oil which would satisfy the criteria you mention for "an oil high in detergents and with a high base number to neutralize acids" which would be suitable for a car that spends a lot of time in the garage. I do, of course, give it a decent thrashing from time to time...........

Thanks in advance,

Ron

 

High detergent motor oils: (a quick look)
Mobil 1 Truck Turbo Diesel 5W-40 -- HTHS is a little low for track use.
RedLine 10W-40
AmsOil 10W-40 AMOQT-EA

Many of the truck and SUV oils have the detergent package and base number for garage queen vehicles, however few of these have the HTHS number. But, still, the key is to figure out how to find the data you want. In general you dial up the manufacture site via google, and then find the oil in question and then find the technical data sheet and read it.

 

Wow! i may be more confused now than what i was before. I was thinking about using the redline oil because everyone says that it is good stuff. I drive my car every fri, sat, and sun(weather permitting) and i dont drive it hard most of the time.

 

I second the Amsoil 10w40

 

RedLine is good stuff and is the only 0W-30 oil I have found to have a high enough HTHS to go racing.....And I actually have done this.....And survived.....And so did the car.....

 

Amsoil 0W-30 also has a HTHS of 3.2, and Castrol 0W-30 European Formula (formerly known as German Castrol) is >3.5.