What oil wt. ?? Nascar

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Jan 18, 2003
About 10 years ago I read that some of the Nascar teams had tightened up bearing clearances some, and were running a 10w - 30 oils. Did that work out? Or what wt. are they running?
I believe that they run 20w-50, straight 50 and straight 60 weight racing oils.

The 10w-30 is only used for qualify. (2-3 laps max before changing to the heavier stuff)
It would be very interesting to see a UOA on their oil after a race! Probably ends up having 5% fuel in it, and the viscosity drops down a grade or two (which is why they'd run the thicker oils for the actual race)
I can GUARANTEE you there is not 5% fuel in the oil after a race or they would never pass the oil test. AND the guys setting up their carbs are tuning for gas mileage so I'm sure they are not errantly dumping fuel in the crankcase.
"AND the guys setting up their carbs are tuning for gas mileage so I'm sure they are not errantly dumping fuel in the crankcase." ...especially this season, where more than one race has been decided by fuel economy!
But, what's the sump capacity??? 16 qts or something??? And there's one or more oil coolers?
With Havoline, Valvoline, Quaker State, Pennzoil, and some others as sponsors, I'd doubt seriously that they all use the same fluids. I know #3 always used Union 76 products. Also they hold 22 qts.

Originally posted by DavoNF:
I don't know, so I'll ask, what's a dry sump system?

"Sump" oil is held in a seperate tank outside the engine, instead of just chillin in the oil pan, which means either more than one oil pump must be used, or they make oil pumps that have up to 3 or 4 ports for either direct feed to the engine and crankecase evacuation of oil to be brought to the oil tank.
Sunoco Signs 10-Year Deal to Supply Fuel to NASCAR

BROOKLYN, Mich. (Aug. 15) -- Sunoco, the world's largest manufacturer of premium racing gasoline, will replace Union 76 as NASCAR's official fuel supplier, beginning in 2004.

NASCAR made the announcement Friday morning at Michigan International Speedway, the site of this week's Winston Cup Marketplace 400 and Busch Series Cabela's 250.

Under the 10-year agreement, Sunoco will provide fuel for NASCAR's three leagues -- the Nextel Cup, Busch Series and Craftsman Truck series. Nextel replaces Winston Cup as the series title sponsor next year.

"Because our sport literally runs on gasoline, this partnership is one of the most important relationships for NASCAR," NASCAR president Mike Helton said. "Sunoco has a well-earned reputation for producing the highest-quality racing gasoline and for reliably distributing it to race tracks.

"In our NASCAR Dodge Weekly Series association with Sunoco, we have been impressed with Sunoco's people, products and passion for our sport. We are proud to welcome them as the official fuel of NASCAR."

Sunoco distributes gasoline to more than 400 race tracks in the United States and already has a relationship with NASCAR as the gasoline supplier to approximately 80 percent of the Dodge Weekly Series that competes at 75 tracks.

"Union 76 has been a trusted and valued partner for more than 40 years," Helton said. "We've enjoyed our long successful relationship and would like to thank 76 for their support and partnership in helping grow NASCAR through the years."

Due to a shift in the company's marketing strategy, Conoco Phillips decided not to renew the 76 fuel supplier contract, which expires at the end of this year.

08-15-03 10:38 ET
Synergyn "Nascar Oil"

3W-30 oi

Typical Specifications:
SAE Grade Viscosity
@40 Decrees C.
@100 Degrees C. 67.8
Viscosity Index 146
API Gravity7 29.12
Specific Gravity 0.881
Density, Lbs/Gal. 7.35
Flash Point, Degrees F 410
Pour Point, Degrees F -40

SAE Grade 0w - 20 Weight Engine Oil
Viscosity @ 40 Degrees C 48.2
Viscosity @ 100 Degrees C 8.8
Viscosity Index 165
API Gravity 31.7
Specific Gravity 0.867
Flash Point, Degrees F 410 Degrees F
Pour Point, Degrees F -65 Degrees F

They also make LTS 0, 00, 000, 0000 oils LOL
I was watching Inside Winston Cup on Speed Channel last night and one of the letters they answered was from a Canadian - Patman, is that you?

The question was - What oils do the cars use?

Johnny Bensen answered - 0-10 weight for qualifiying and 20W50 for racing, all synthetic.

Stll not much info and what's a 0-10 weight...
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