NASCAR rear differential - open?
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TECH Fanatic
Joined: Oct 2002
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From: Dallas, North Mexico
NASCAR rear differential - open? I tried searching around- but I was thinking about this. Since they only turn left and given the driveshaft rotation direction- with enough wheel bias, the only wheel that would be powered would be the outside wheel- which is ideal.
So do they run an open rear? Well, I know the answer is no because i've seen them do burnouts. I guess the question is "why?"
So do they run an open rear? Well, I know the answer is no because i've seen them do burnouts. I guess the question is "why?"
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Joined: Jun 2002
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From: Upstate NY
Yes and no. On big tracks where off-the corner traction isn't a problem it's open. On short tracks and road courses it's probably something like a Detroit Locker.
Anyplace where the engine rpm runs 3 or 4000 from lowest to highest traction will be a problem, so some form of limited slip is used. IF there was traction control in Cup cars
the tracks that needed it would also be the tracks where a locker would be used.
Especially on a long high-speed tracks any form of locking diff would cost power. As a possible added benefit for the "plate" tracks (Daytona, Talladega) spinning one tire launching out of the pits keeps the engine from bogging or stalling. Notice how long they are in first gear on pit-out @ Daytona. It's not just used for getting the car rolling. Trying to spin both @ Daytona might be a problem with an engine weaker than most H&C LT1s.
Did you notice that the highest horsepower car on the track @ the Daytona 500 was the stock Z06 pace car?
Anyplace where the engine rpm runs 3 or 4000 from lowest to highest traction will be a problem, so some form of limited slip is used. IF there was traction control in Cup cars
the tracks that needed it would also be the tracks where a locker would be used.Especially on a long high-speed tracks any form of locking diff would cost power. As a possible added benefit for the "plate" tracks (Daytona, Talladega) spinning one tire launching out of the pits keeps the engine from bogging or stalling. Notice how long they are in first gear on pit-out @ Daytona. It's not just used for getting the car rolling. Trying to spin both @ Daytona might be a problem with an engine weaker than most H&C LT1s.
Did you notice that the highest horsepower car on the track @ the Daytona 500 was the stock Z06 pace car?
Originally Posted by Old SStroker
Did you notice that the highest horsepower car on the track @ the Daytona 500 was the stock Z06 pace car?
Steve
You used to be able to run an open diff.. at Speedways like Daytona and Taladega... but its lockers on all tracks now.... The pace car might have a small bit more Hp but I'd like to see it hang in the draft.... that would be funny too see a pack of 10 cars pass it like it was in reverse.....
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Joined: Nov 2002
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From: Berkeley, California
Originally Posted by Old SStroker
Did you notice that the highest horsepower car on the track @ the Daytona 500 was the stock Z06 pace car?
Originally Posted by Gary Z
I don’t follow NASCAR but while zapping through the channels Sunday, I noticed engines turning 9500 rpm. At 350 cubic-inches they are probably making at least 700 hp.
the thing about the plate tracks is that they rely more on the draft for speed. the Z could do it without the draft. the true test for it would be if it could hang in the turns. which according to the nurburgring lap times...it should be able to do it without trying. the Z is a better handling car overall. id just like to see the motor stay together with the abuse the plate tracks put on the motors
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From: Upstate NY
Originally Posted by Gary Z
I don’t follow NASCAR but while zapping through the channels Sunday, I noticed engines turning 9500 rpm. At 350 cubic-inches they are probably making at least 700 hp.
Daytona and Talladega have restrictor plates. HP is closer to 425 and max rpm closer to 7500 at those tracks.
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when i was going to the Nascar Technical Institute in Mooresville our 358ci Dodge motor made 738 hp and just over 550 ft/lbs on the engine dyno. we were limited how high we could turn the motor, but the school record was set by one of the instructors (who had 10 years of Cup motor building experience) who made right around 750
and i think we made in the 680s hp to the wheels on the chassis dyno.
and i think we made in the 680s hp to the wheels on the chassis dyno.
I dont know how you'd compare the nurburgring to Daytona..... I would be willing to bet from pace car speed the cup car would out accelerate the vette... Theres no way that a stock suspension vette would be able to run through the bumps at Daytona
big bronco (mod on here) from SAM caem to my school and did a presentation on how much School of Automotive Machinists rocks. He said they have about 600 hp, and about 300 with the plates on.
Originally Posted by 3.4camaro
big bronco (mod on here) from SAM caem to my school and did a presentation on how much School of Automotive Machinists rocks. He said they have about 600 hp, and about 300 with the plates on.
Originally Posted by Old SStroker
You were watching California, an unrestricted track. More like 850 hp from the 358 cubes.
Daytona and Talladega have restrictor plates. HP is closer to 425 and max rpm closer to 7500 at those tracks.
Daytona and Talladega have restrictor plates. HP is closer to 425 and max rpm closer to 7500 at those tracks.
Originally Posted by 3.4camaro
big bronco (mod on here) from SAM caem to my school and did a presentation on how much School of Automotive Machinists rocks. He said they have about 600 hp, and about 300 with the plates on.
they use lockers, open diffs(which i think might be illegal now), and spools depending on the track. I got one of the NASCAR cup car Lockers from a shop in NC. It's in my 9" now, and MAN, this thing is a work of art, haha.