Endurance Racing Tips

Anyways, yes, Champ Car, not Lemons. I believe any external oil cooler would incur the penalty, yes, even a factory style. We are already starting at a 5 lap disadvantage, and we have to take another lap or two for other "mandatory" changes (driveshafts on these cars tend to come apart over 120 MPH or so and we may take a penalty for an adjustable panhard bar just to get the rear axle positioned back after lowering). We heavily considered using the factory AC evaporator and trying to fly it under the radar just in case...but we decided it wasn't the risk of it running into the cabin and trying to leakproof it.

I took a glance at the champcar rules shortly after reading this thread and I think you are right. It says "non-OE". On one hand in my mind that leaves it fairly open to interpretation for ideas like Vermeers with OE internal radiator trans coolers etc, but I'm sure if a tech sees oil lines going from a filter block to the radiator they might disagree, lol. Maybe subtly ask some guys who have had their cars tech'ed at these races before to get an idea of how stringent it is.
I don't fear hot oil, I fear overheated oil lol. Oils do break down or at least become much less protective at some point. I may be wrong in what you're doing with yours, but I don't really think that any amount of street driving is anywhere close to wheel-to-wheel racing for fourteen hours straight. To my mind, there's a reason that Ford switches from 5W-20 to 15W-50 on all the factory high-performance applications, and we're going to be pushing this engine harder than they probably planned for even on those. So I consider that the minimum as far as I can understand things.

I'm a seasoned racer, been around it my whole life. What do you consider overheated? When I say hot, I'm talking about hitting 280-300°F. These engines are very durable. Ford recommends 50 grade oil with performance use likely as a CYA in case someone decides to pour in the cheapest conventional gas station oil so that there's a big buffer room. They're thinking about warranty claims. There's plenty of these engines that see endurance racing on 20 grade oils and are just fine.

I consider heavy towing to actually be worse than what you're doing. It's low rpm and high load which puts more stress on the oil film in the bearings and around the rings. You're spinning much higher rpm with less constant load. As crank journal speed increases, the journal becomes more centric in the bearing and planes easier on the oil film which reduces the minimum oil film thickness necessary to maintain hydrodynamic lubrication. High rpm needs better anti-wear, friction modifier, and extreme pressure additives to better handle the higher loads in the valvetrain from parts accelerating on and off the seat faster. Good anti-aeration / anti-foaming chemistry is important as well. For what you're doing, I would much rather have a stout 20 or 30 grade oil with a killer add pack than I would any 50 grade.

Run a 50 grade if you want, by all means, but I don't think you'll see any real benefit from doing so. I think you'll just be throwing away power at best. At worst, the higher viscosity ends up running even hotter due to higher hydrodynamic friction and the naturally higher specific heat capacity that comes with higher viscosity. You could also face more aeration concerns, as higher viscosity is also naturally more prone to aeration, which can also cause oil temps to increase.
And for the record the COF of the additive package in the oil Rdy4war is recommending reaches its peak at 300f. With excellent AW.

It seems something like our BAS 5w40 would be a good choice for you. This is what we run in winged sprint cars north of 900 hp. The wings act as a parachute at speed and create tremendous load. 280F oil temps are normal in very short order.