I went to the nhra nationals yesterday....

The_Jed wrote: A while back someone here posted a ton of info about Dodge/Chrysler top fuel or funny car engines. The one tidbit that stood out most to me was it takes 600 hp just to turn the supercharger at peak boost.

That's because they are using really efficient superchargers!

I was poking around a Top Alcohol car and was told that the screw compressor they just switched to required a lot less power and made 60psi boost... the old Roots blower (air crammer, not a compressor) needed 1000hp to make 45psi.

This on an engine that maybe makes 2000hp.

In reply to chuckles:

Yep, 1000 ft

Have no idea how true any of the folling is but makes for good reading!

• One dragster's 500-inch Hemi makes more horsepower then the first 8 rows at Daytona.

• Under full throttle, a dragster engine consumes 1 1/2 gallons of nitro per second, the same rate of fuel consumption as a fully loaded 747 but with 4 times the energy volume.

• The supercharger takes more power to drive than a stock hemi makes.

• Even with nearly 3000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into nearly-solid form before ignition. Cylinders run on the verge of hydraulic lock.

• Dual magnetos apply 44 amps to each spark plug. This is the output of an arc welder in each cylinder.

• At stoichiometric (exact) 1.7:1 air/fuel mixture (for nitro), the flame front of nitromethane measures 7050 degrees F.

• Nitromethane burns yellow. The spectacular white flame seen above the stacks at night is raw burning hydrogen, dissociated from atmospheric water vapor by the searing exhaust gases.

• Spark plug electrodes are totally consumed during a pass. After 1/2 way, the engine is dieseling from compression-plus the glow of exhaust valves at 1400 degrees F. The engine can only be shut down by cutting off its fuel flow.

• If spark momentarily fails early in the run, unburned nitro builds up in those cylinders and then explodes with a force that can blow cylinder heads off the block in pieces or blow the block in half.

• Dragsters twist the crank (torsionally) so far (20 degrees in the big end of the track) that sometimes cam lobes are ground offset from front to rear to re-phase the valve timing somewhere closer to synchronization with the pistons.

• To exceed 300mph in 4.5 seconds dragsters must accelerate at an average of over 4G's. But in reaching 200 mph well before 1/2 track, launch acceleration is closer to 8G's.

• If all the equipment is paid off, the crew worked for free, and for once NOTHING BLOWS UP, each run costs $1000.00 per second.

• Dragsters reach over 300 miles per hour before you have read this sentence.

Did you know …

… that the nitromethane-powered engines of NHRA Top Fuel dragsters and Funny Cars produce approximately 7,000 horsepower, about 37 times that of the average streetcar?

… that one cylinder of the eight cylinders of a Top Fuel dragster or a Funny Car produces 750 horsepower, equaling the entire horsepower output of a NASCAR engine?

… that the gasoline-powered engines of NHRA Pro Stock cars produce about 1,200 horsepower, about eight times that of the average street car?

… that an NHRA Top Fuel dragster accelerates from 0 to 100 mph in less than .8-second, almost 11 seconds quicker than it takes a production Porsche 911 Turbo to reach the same speed?

… that an NHRA Top Fuel dragster leaves the starting line with a force nearly five times that of gravity, the same force of the space shuttle when it leaves the launching pad at Cape Canaveral?

… that an NHRA Funny Car is slowed by a reverse force more than seven times that of gravity when both parachutes deploy simultaneously?

… that NHRA Top Fuel dragsters and Funny Cars consume between four and five gallons of fuel during a quarter-mile run, which is equivalent to between 16 and 20 gallons per mile?

… that NHRA Top Fuel dragsters and Funny Cars use between 10 and 12 gallons of fuel for a complete pass, including the burnout, backup to the starting line, and quarter-mile run?

… that NHRA Top Fuel dragsters and Funny Cars travel the length of more than four football fields in less than five seconds?

… that NHRA Top Fuel dragsters can exceed 280 mph in just 660 feet?

… that from a standing start, NHRA Top Fuel dragsters accelerate faster than a jumbo jet, a fighter jet, and a Formula One race car?

… that a fuel pump for an NHRA Top Fuel dragster and Funny Car delivers 65 gallons of fuel per minute, equivalent to eight bathroom showers running at the same time?

… that the fuel-line pressure for NHRA Top Fuel dragsters and Funny Cars is between 400 and 500 pounds, about 20 times greater than the pressure on passenger-carfuel pumps?

… that depending on size and angle, the large rear wing on an NHRA Top Fuel dragster develops between 4,000 and 8,000 pounds of downforce?

… that the 17-inch rear tires used on NHRA Top Fuel dragsters and Funny Cars wear out after four to six runs, or about two miles? Some brands of passenger-car tires are guaranteed for 80,000 miles.

… that it takes just 15/100ths of a second for all 7,000 horsepower of an NHRA Top Fuel dragster engine to reach the rear wheels?

… that it's desirable for an NHRA Top Fuel dragster to race with its front wheels inches off the ground for about the first 200 feet of the run? This ensures proper weight transfer to the rear wheels, a crucial part of a good launch and quick run.

… that the nitromethane used to power the engines of NHRA Top Fuel dragsters and Funny Cars costs about $30 per gallon?

And the intake valves are roughly the same diameter as a beer can.

So are the TWIN fuel lines.

These are just from my eyeball measurements

I like the class that races against an arbitrary number. Computer shuts off the engine then lights it back up to try to hit the 1/4 mile time.

My brother was out there but we had visitors. I hope to make it out next year.

chandlerGTi wrote: I like the class that races against an arbitrary number. Computer shuts off the engine then lights it back up to try to hit the 1/4 mile time. My brother was out there but we had visitors. I hope to make it out next year.

That's most of them, I thought. Seems like a lazy way to race, build a car to run hard and then dial it back with electronics so it runs exactly 9.90 or whatever. They are the reason why most amateur-night bracket racing is "NO BOX" and they don't even let you have a laptop plugged in for datalogging.

Ha, I'm good with the "no box" racing but those cars are just wicked fast.

I love "grassroots" racing but seeing guys with unlimited budgets is a lot of fun!

We used to run a car at Marion County Intl Raceway, which is an ihra track. The biggest class on any given saturday was always "Modified No Box". No delay boxes, but trans brakes were allowed. Most of the car were in the 10.5-13 second range. You had whatever dial in and the slower cars had head start. Ive been thinking about getting back into it. Ihave a friend who runs at a nhra track so i figured id race with him but i havent fully grasped the nhra indexing time system yet. If somebody can give me a simple explanation I sure would appreciate it.