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Discussion Starter #1
My step-son watched Elliot Sadlers superspeedway car get dyno'd today. He loved the experience!
690 hp at the flywheel, 678 at the rear wheels!
 

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How can he only lose 12 HP through the drivetrain? Normal loss is 18%. Could your post have a typo in it?

GT40 Bill
 

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Only 12 hp?
I'd sure like to know what tricks those old boys have up their sleeves!
If that was a superspeedway car,wouldn't it have a restrictor plate on it?
Joe
 

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Yes it would have a restrictor plate on it. Without the plate, it would have been between 750 and 800 horsepower.
 

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Discussion Starter #7
It was a restrictor motor, but had no restrictor plate on it during the tests.

The dyno tests were at UTI's NASCAR TECH in Mooresville.

Those are the numbers he gave me over the phone. Of course they might be way off, I've never heard anyone that excited about anything! He was only 5 feet from the car when they ran it up to 200 mph. Heck, he was still talking at 200 mph 10 hours later.
 

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It's actually pretty easy to explain the minimal HP loss through the drivetrain on this car.

NASCAR requires that the cars use the same engines in both qualifying and the race. They don't - however - require them to use the same clutch, flywheel, transmission and differential - or - lubricants...

It is quite common for them to use 0w-20 motor synthetic motor oil, mineral oil for the "shaved straight cut gear" transmission and the 1" wide ring-gear - open differential. The clutch is a Tilton carbon fiber 5" disc on a lightweight steel flex-plate. Driveshaft / pinion angle is precisely controlled for minimal loss.

Now these "Qualifying" components are not very long lived. They don't need to be as they only run 3 laps. You will notice when watching them qualify, that you never see them dump the clutch and burn rubber out of the pit. The driveline would literally shatter from one end to the other. Power / load needs to be applied gradually - as in a dyno.
 
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