Daytona 500 engine related question

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I was watching Daytona 500 and one or 2 of the cars were steaming a little at one point. 1- One of the announcers said not much air is getting in since they are drafting ... I can understand this one. 2- Later another guy said they tape off the grill or parts of it to go faster. Is this for aerodynamics or for keeping the engine hot? it kind of contradicts #1 3- Later they said the temperatures are dropping so the cars would be able to go faster. Does this have to do with tires and the track and/or increased amount of oxygen? otherwise colder air is denser if we are talking aerodynamics and cooler engine temps (if any and/or significant) contradicts #2. I can't connect some of the dots. Please help! LOL
 
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Closing off the grille makes the car more aerodynamic. They tape as much as they can without overheating the engine. Cooler air is denser, meaning there will be more mass of oxygen in the cylinders for a given pressure and volume. Since there is no turbo or supercharger, the engine has to operate at atmospheric pressure.
 
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Yup, that's why a corn dog wrapper getting sucked onto the radiator will totally ruin your day as a driver. wink
 
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Its that fine balance between just enough airflow and restriction. That is why you always see them cleaning the grille on every stop and either adding or removing tape. This new generation engine can withstand super high water temps much better than the older designs.
 
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Great article with a bunch of video links about this very topic: https://jalopnik.com/the-fascinating-reason-why-nascar-engines-run-so-hot-1835071544 Highlights: Coolant temp is a product of how much air flows through the radiator and nothing else Engines do not run a thermostat of any type 290 F is a totally normal coolant temperature; teams start pulling tape when coolant temps are above 300 F and adding tape when temps are below 280 F Oil temps are 300+ F Cooling systems are pressurized to 100 PSI Qualifying is done with the radiator opening fully taped; 330 F during qualifying is typical A cool down unit is plumbed to the car in between qualifying attempts to keep temps in check
 
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It's pretty crazy how they operate. The oil sump temp is ~280*F with a 60-75*F temperature rise through the bearings. The oil is a light 0w-20 / heavy 0w-16 (KV100 = ~7.5 cSt) that is mostly group III with a good bit of PAO/mPAO and POE to push the flash point higher and help it take the heat. It's also a low detergent oil (<500 ppm Ca) with Zn/P in the 800-1000 ppm range and Mo in the 1000-1800 ppm range. The Sonny Bryant crankshafts for those engines is a true masterpiece. The machining is incredibly precise and smooth.
 
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Originally Posted by RDY4WAR
It's pretty crazy how they operate. The oil sump temp is ~280*F with a 60-75*F temperature rise through the bearings. The oil is a light 0w-20 / heavy 0w-16 (KV100 = ~7.5 cSt) that is mostly group III with a good bit of PAO/mPAO and POE to push the flash point higher and help it take the heat. It's also a low detergent oil (<500 ppm Ca) with Zn/P in the 800-1000 ppm range and Mo in the 1000-1800 ppm range. The Sonny Bryant crankshafts for those engines is a true masterpiece. The machining is incredibly precise and smooth.
I hear they run even lower viscosity oil for qualifying, only has to last a couple laps and from a near stone cold engine.
 
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Originally Posted by sloinker
Originally Posted by RDY4WAR
It's pretty crazy how they operate. The oil sump temp is ~280*F with a 60-75*F temperature rise through the bearings. The oil is a light 0w-20 / heavy 0w-16 (KV100 = ~7.5 cSt) that is mostly group III with a good bit of PAO/mPAO and POE to push the flash point higher and help it take the heat. It's also a low detergent oil (<500 ppm Ca) with Zn/P in the 800-1000 ppm range and Mo in the 1000-1800 ppm range. The Sonny Bryant crankshafts for those engines is a true masterpiece. The machining is incredibly precise and smooth.
I hear they run even lower viscosity oil for qualifying, only has to last a couple laps and from a near stone cold engine.
They may run an even lower viscosity oil for qualifying to gain a hp or two, but the engine they qualify with is same engine they race with. If they change engines then they start last. And also if you notice there's a small cart looking box behind each race car while on pit road waiting to qualify, that's a heater to keep the fluids up to normal operating range
 
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I havent watched NASCAR in awhile.. i used to enjoy it though. Are there even any chevy, ford, dodge or toyota parts on these vehicles or just sponsorship stickers?
 
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Originally Posted by RDY4WAR
It's pretty crazy how they operate. The oil sump temp is ~280*F with a 60-75*F temperature rise through the bearings. The oil is a light 0w-20 / heavy 0w-16 (KV100 = ~7.5 cSt) that is mostly group III with a good bit of PAO/mPAO and POE to push the flash point higher and help it take the heat. It's also a low detergent oil (<500 ppm Ca) with Zn/P in the 800-1000 ppm range and Mo in the 1000-1800 ppm range. The Sonny Bryant crankshafts for those engines is a true masterpiece. The machining is incredibly precise and smooth.
Very interesting info. Thanks! Do we know who makes their engine oil, transmission and differential fluid? Or the specs of the transmission and differential fluids?
 
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Originally Posted by Gebo
Originally Posted by RDY4WAR
It's pretty crazy how they operate. The oil sump temp is ~280*F with a 60-75*F temperature rise through the bearings. The oil is a light 0w-20 / heavy 0w-16 (KV100 = ~7.5 cSt) that is mostly group III with a good bit of PAO/mPAO and POE to push the flash point higher and help it take the heat. It's also a low detergent oil (<500 ppm Ca) with Zn/P in the 800-1000 ppm range and Mo in the 1000-1800 ppm range. The Sonny Bryant crankshafts for those engines is a true masterpiece. The machining is incredibly precise and smooth.
Very interesting info. Thanks! Do we know who makes their engine oil, transmission and differential fluid? Or the specs of the transmission and differential fluids?
Driven supplies the oils and fluids for about half the field.
 
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Originally Posted by OilUzer
I was watching Daytona 500 and one or 2 of the cars were steaming a little at one point. 1- One of the announcers said not much air is getting in since they are drafting ... I can understand this one. 2- Later another guy said they tape off the grill or parts of it to go faster. Is this for aerodynamics or for keeping the engine hot? it kind of contradicts #1 3- Later they said the temperatures are dropping so the cars would be able to go faster. Does this have to do with tires and the track and/or increased amount of oxygen? otherwise colder air is denser if we are talking aerodynamics and cooler engine temps (if any and/or significant) contradicts #2. I can't connect some of the dots. Please help! LOL
2. Lower aero drag from blocking off the radiator. 3. Lower track temperatures improves grip.
 
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Originally Posted by MrHorspwer
Great article with a bunch of video links about this very topic: https://jalopnik.com/the-fascinating-reason-why-nascar-engines-run-so-hot-1835071544 Highlights: Coolant temp is a product of how much air flows through the radiator and nothing else Engines do not run a thermostat of any type 290 F is a totally normal coolant temperature; teams start pulling tape when coolant temps are above 300 F and adding tape when temps are below 280 F Oil temps are 300+ F Cooling systems are pressurized to 100 PSI Qualifying is done with the radiator opening fully taped; 330 F during qualifying is typical A cool down unit is plumbed to the car in between qualifying attempts to keep temps in check
Didn't know a lot of that!! Thanks for sharing!
 
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Originally Posted by krismoriah72
I havent watched NASCAR in awhile.. i used to enjoy it though. Are there even any chevy, ford, dodge or toyota parts on these vehicles or just sponsorship stickers?
wonder that myself
 
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Originally Posted by faltic
Originally Posted by krismoriah72
I havent watched NASCAR in awhile.. i used to enjoy it though. Are there even any chevy, ford, dodge or toyota parts on these vehicles or just sponsorship stickers?
wonder that myself
Certain body parts come from the manufacturers. The spoiler is a spec part from Richardson Racing Products. The Toyota engines are built by TRD, Ford engines by Roush Yates, and most of the Chevrolet engines by either Hendrick or ECR/RCR.
 
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I think the engine block, cylinder heads, and intake manifold must have OE manufacturers part numbers on them, and each design is approved by NASCAR. Maximum bore is 4.185 inches, maximum bore spacing is 4.500 inches. Block material must be cast iron. Maximum compression ratio is 12.0. Since Toyota didn't have a pushrod V8 when they entered NASCAR, they were allowed to design basically a dedicated pushrod racing engine. Then the other manufacturers complained that Toyota was taking advantage, so they were allowed to design dedicated 4.500 bore spacing engines. No parts interchange with traditional small block Chevy or Ford production engines. Water jacket design is especially elegant. The blocks are now cast from compacted graphite iron, which is about twice the tensile strength of most gray cast irons. The blocks last for years of competition.
 
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[img]https://photos-e1.flightcdn.com/photos/retriever/5866f956bec5f81b2ec5ea4218d0b319a43f43ee[/img] [img]https://www.emapa.aero/Cessna-Cowlabunga-LoPresti-Aviation-p/cessna-cardinal-cowlabunga.htm[/img] [Linked Image from flyingbooth.co.uk] Same plane, one is 7kts faster due to lower cooling drag. These planes fly around 140-165MPH, considerably slower than NASCAR. The bottom line is that a certain amount of airflow is required for cooling. Any excess airflow through a radiator (or fins of an air cooled engine) creates "cooling drag" . As it takes work to force the air through such a restriction.
 
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I remember the WW2 P51D Mustang used the radiators out under the wings in special enclosures as extra thrust, and got a 20 MPH speed advantage from the way these were ducted. The hot air coming out of the ducts was slightly faster than the speed of the plane, generating thrust along the way.
 
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