Engine oil temps

[hoffman900]

Because if you don't and somebody else is they will outrun you. Thermodynamics. The more you heat the air you pass through the engine the more power you can make, as long as engine parts are not damaged.

I think it’s more about aerodynamics.

No, it is heat, thermodynamics. More heat makes more power.

More heat is more tape on the grill. Hence the high water pressures / water temp. Aero almost always takes precedence, especially at the average speeds they run.

[Steve.k]

I think it’s more about aerodynamics.

No, it is heat, thermodynamics. More heat makes more power.

More heat is more tape on the grill. Hence the high water pressures / water temp. Aero almost always takes precedence, especially at the average speeds they run.

So the — many mph they gain from taping grille shut gains but the expense is heat. Design engine around the short comings of added temp.In all reality you would really like to run as cool as possible.If things go sideways the hotter u are the less time u have.

[Tuner]

I think it’s more about aerodynamics.

No, it is heat, thermodynamics. More heat makes more power.

More heat is more tape on the grill. Hence the high water pressures / water temp. Aero almost always takes precedence, especially at the average speeds they run.

I get what you're saying, but that is a different subject. In the engine, more heat is more power as long as it is under control so causes no damage.

[Tuner]

No, it is heat, thermodynamics. More heat makes more power.

More heat is more tape on the grill. Hence the high water pressures / water temp. Aero almost always takes precedence, especially at the average speeds they run.

So the — many mph they gain from taping grille shut gains but the expense is heat. Design engine around the short comings of added temp.In all reality you would really like to run as cool as possible.If things go sideways the hotter u are the less time u have.

When the racing rules only give you a finite amount of air by specifying a throttle bore or restrictor plate size, to get the most power you need to get as much heat from that air as you can.

[peejay]

Because if you don't and somebody else is they will outrun you. Thermodynamics. The more you heat the air you pass through the engine the more power you can make, as long as engine parts are not damaged.

I think it’s more about aerodynamics.

No, it is heat, thermodynamics. More heat makes more power.

Maybe "less temperature delta between combustion and everything else makes more power"? Methanol burns pretty cool and you can make a lot of power with it.

I forget which NASCAR engine guy said it, but he said at a seminar that while your instinct is to get more air and fuel INTO the engine to make more power, the truth was they were burning 2400hp worth of fuel and air to make 900hp, so that was 1500hp worth of air and fuel already getting to the engine that were being lost as heat, either through the cooling system directly, cooling system indirectly through friction losses, or just plain blown out the tailpipe as exhaust energy. So their main focus in engine development was in minimizing how much energy you lose, because 1500hp is a very large number.

With that in mind, 325F oil temps and 250F coolant temps make a lot of sense. There's a lot less temperature delta, so less energy gets lost to the cooling systems.

WITH ALL THAT SAID.... I have been out of the loop for a while. Do modern NASCAR engines need to be preheated before you can start them, like old F1 engines? Supposedly you couldn't even turn a DFV unless you preheated the oil and coolant to operating temperature first.

[Steve.k]

So you are finding the air takes less fuel/oxy to heat to make same power with limited intake cfm. Wow that’s really changing the scope of things now. Im no physicist so it could be. In your sport its real tight to get gains thats for dam sure.

[MadBill]

Do remote sump systems operate this high?

They can. Our dry sump SBF road racer with Driven 10W-30 runs hotter than we'd like, as much as 300°. (water never goes over 180° on the track) After five seasons, bearings have remained looking so good we haven't changed them. (they've effectively undergone really extensive QC testing, unlike any new from the box part.)
Somewhere I read an article that made indirect reference to some circle track teams running 325° or more. Can't imagine why though..

Bill,
do you find these temps load sensitive or is the temp constant during a race or qualifying??
i am interested in your thoughts on the oil you use for that engine,i like and use the break in oil but have never ran other grades from Driven.

Yes, the oil temp is quite load-sensitive but that said, unless the ambient is well above or below our mid-season average of ~ 80° F. it stabilizes after ~ 10 racing miles in the 280° -300° range. With the thermal mass of 18 quarts in the system, it doesn't fluctuate noticeably through a lap and takes a couple of laps to drop under extended yellows.

As far as oil choice [a slippery (groan) subject], we did a lot of research before going with the Gibbs product and in six seasons nothing has impelled us to experiment.

[steve cowan]

Thank you Bill for the feedback
Glad you found a oil you like

[midnightbluS10]

I think it’s more about aerodynamics.

No, it is heat, thermodynamics. More heat makes more power.

Maybe "less temperature delta between combustion and everything else makes more power"? Methanol burns pretty cool and you can make a lot of power with it.

I forget which NASCAR engine guy said it, but he said at a seminar that while your instinct is to get more air and fuel INTO the engine to make more power, the truth was they were burning 2400hp worth of fuel and air to make 900hp, so that was 1500hp worth of air and fuel already getting to the engine that were being lost as heat, either through the cooling system directly, cooling system indirectly through friction losses, or just plain blown out the tailpipe as exhaust energy. So their main focus in engine development was in minimizing how much energy you lose, because 1500hp is a very large number.

With that in mind, 325F oil temps and 250F coolant temps make a lot of sense. There's a lot less temperature delta, so less energy gets lost to the cooling systems.

WITH ALL THAT SAID.... I have been out of the loop for a while. Do modern NASCAR engines need to be preheated before you can start them, like old F1 engines? Supposedly you couldn't even turn a DFV unless you preheated the oil and coolant to operating temperature first.

Was it this one? I seem to remember hearing that in this.

[David Redszus]

The topic of oil temperature cannot be separated from other operating parameters that affect wear and reduced friction.

Starting with viscosity (cSt) vs temperature for various oils:

Temp F...10w-30.....5w-50......20w-50 cSt

200...........13.5........21.9.........23.5

250............8.0........13.2..........12.9

300............4.9.........8.2...........7.3

350............3.5.........5.9...........5.0

Typically, OEMs will specify a minimum viscosity value of 3.5 cSt, depending on point of lubrication and
mode of operation.

The first issue involves which part of the engine we are seeking to lubricate properly: bearings, cams, rings,
pistons. They all run at different temperatures and are not the same as oil sump temperatures; they are typically
much higher. Where are we measuring oil temperature and in how many locations?

While water does boil at 212F (at sea level), the pressure in the oil galley is much higher and causes the water to
boil at a much higher temperature. Race engines should not be concerned since the oil is changed frequently.
If not, then the greater concern is acid formation due to incomplete combustion products; mostly nitric acid.

The optimum oil viscosity for engine bearings that will minimize wear, is a function of bearing size, bearing
load, oil temp, and rpm as predicted by the Stribeck curve.

[Steve.k]

Thanks everyone for imput. Very good discussion and way more to it than I realized.