Out of the darkness. Exclusive Top Fuel Dragster power test (1 Viewer)

[.]

I remember back in the early 2000's, an issue of the National Dragster had 8000HP in big number across the front cover. The article inside explained how they installed a strain gauge on the drive shaft of Doug Kalitta's dragster. It made 7933hp at 2.6 seconds after the hit, on a 4.4something 1/4 mile pass.... which at the time was a very quick ET for 1/4 mile racing. This is all from my memory... if one of those ND collectors out there could pull this issue out of their archives it would be cool to read the article again. I'm pretty sure it was early 2000's but it could have been late 90's, like Brent mentioned above. It had a mostly black cover with 8000HP across the cover in big numbers.

The one thing that always got me was how they test for HP. Measuring torque, then mathematically calculating HP is great but you're only measuring the amount of HP being applied to the ground on that track, in that lane, on that day. If the tires spin, the torque numbers fall off to near zero, which means low HP numbers, right? What if the opposite happened? What if the track surface and the rear tires were made out of VELCRO, and you had FAR MORE traction than just two rubber tires on concrete/asphalt? You could apply MUCH more HP before the tires would spin.... what would the torque/HP numbers be then? I'm wondering what the total POSSIBLE horsepower would be with current fuel pump/blower/cylinder head/cubic inch combination. Lets say the track and tires (total traction) could hold 20,000 HP without spinning the tires, would these engines make 20,000HP, or would they cap off somewhere in between? I'm no engineer, just your average guy thinking out loud...

I think the reason 1999 sticks in my mind is because it was before they cut the nitro to 90% in 2000 after Hill's and Herbert's huge explosions that season..

I've often wondered how much power they'd make if we could go back to some of the old rules like 100%, 2.90 gear, big wings, etc. All of that stuff would definitely put a much bigger load on the engine than they see with today's rules. More load = burn more fuel, so the HP would be more. Eventually you'd run out of fuel pump to supply enough fuel, but it sure would be interesting to know how high the numbers could be.

 

[.]

I think the reason 1999 sticks in my mind is because it was before they cut the nitro to 90% in 2000 after Hill's and Herbert's huge explosions that season..

I've often wondered how much power they'd make if we could go back to some of the old rules like 100%, 2.90 gear, big wings, etc. All of that stuff would definitely put a much bigger load on the engine than they see with today's rules. More load = burn more fuel, so the HP would be more. Eventually you'd run out of fuel pump to supply enough fuel, but it sure would be interesting to know how high the numbers could be.

That's kinda what I was getting at with my original post.But I'm not wondering how much power they would make under old rules and engine combinations..... I'm wondering how much more power the engines can make under their current configuration. The way they're testing now really only measures how much power is being applied to the track, NOT how much power the engine is ultimately capable of producing.

 

[stitcherbob]

some info on the superchargers:

"Early Top Fuel engines all used the classic 6-71 GMC supercharger that has grown into the current 14-71. NHRA rules now limit virtually all aspects of the fuel superchargers, including the inlet and outlet dimensions. But that hasn't stopped racers from improving the breed. The latest iteration is the Gibson/Miller supercharger designed by aerodynamicist Tim Gibson and built by Bill Miller Engineering (BME). At 50 percent overdrive, Miller says the blower easily pushes 60 psi of boost pressure (that's four atmospheres), and at 12,450 rpm rotor speed, the Gibson/Miller supercharger is capable of 3,750 cfm. According to Miller, that's an air speed of "about 250" mph exiting the supercharger. Pushing this much air, you would think the blower would be plenty hot at the end of a 3-second pass, but with the 12 gallons per minute of fuel sprayed through just the hat nozzles, Miller says the blower is barely warm to the touch if you were to snuggle up next to it on the return lane. That's because the nitro works to pull the heat out of the air despite the immense power required to drive the blower. Miller estimates it takes between 900 and 1,000 crankshaft horsepower to drive one of his superchargers. Just let that last fact settle in for a moment."


Typical Top Fuel Engine
Displacement: 496ci
Block and head: Aluminum Brad Anderson or Alan Johnson
Bore x stroke: 4.310 x 4.250
Compression ratio: 7.0:1
Cylinder head: Hemispherical
Intake valve: Titanium 2.45 inches
Exhaust valve: Inconel 1.92 inches
Rocker ratio: I = 1.73:1, E = 1.53:1
Camshaft: Mechanical roller
Duration: 290 to 300 degrees at 0.050
Roller lifter: 1.6875 inches in diameter
Valve lift: 0.800
Supercharger: Roots style, 14:71
Boost pressure: 65 psi maximum
Ignition: Twin 44-amp magnetos capable of 50,000 volts
Ignition timing: 52 to 55 degrees BTDC
Fuel pump: Mechanical, 100-plus gal/min
Injection: Mechanical, total of 42 injectors
Fuel: 90 percent nitromethane, 10 percent methanol
Oiling system: Wet-sump
Oil capacity: 12 quarts, 70W oil
Maximum rpm: 8,250 rpm
Maximum hp: 8,000 equal to 16 hp per ci

 

[stitcherbob]

to find out the net gain of the supercharger you could use a Top Alcohol nitro injected motor but you would have to up the cubic inches to 496 and decrease the nitro from 94% to 90%.
Plus cam profiles and static compression ratios would be different ...

 

[Mike]

What you guys are actually asking about (power before everything else) can be found by finding the IMEP (indicated mean effective pressure)

 

[Mike]

The real answer is IMEP (indicated mean effective pressure). This is found by putting transducers in the cylinder and measuring the pressure of the combustion chamber over an engine cycle. Knowing this and the geometry of the engine and using some quality software will give you the answer of what the engine is producing before any of the losses. This info minus the individual losses, blower, pump, mag, etc., will tell you how efficient it really is.

https://en.m.wikipedia.org/wiki/Mean_effective_pressure

 

[JON]

Mike you are right - the engine isn't just doing blower work, it's churning all sorts of stuff round.

 

[Dan]

They make a lot of HP that is the end of my engineering degree.....Bob from the cars I helped on this year a lot of the base top fuel engine stuff has changed basically all more aggressive now especially with only going 1000ft

 

[stitcherbob]

They make a lot of HP that is the end of my engineering degree.....Bob from the cars I helped on this year a lot of the base top fuel engine stuff has changed basically all more aggressive now especially with only going 1000ft

we need an updated data chart

 

[sdwarf36]

42 injectors?

 

[.]

42 injectors?

I'm sure it varies team to team but I bet by the time you add up all of the injectors in the cyl. heads, manifold and above the blower it's close.

 

[none]

Double check the lifter size.......

 

[none]

It's an interesting theory, but you can't just discount some of the power needed to run the engine. For instance, the oil pump on a Pro Stock engine is driven by a belt off the crank snout. Now it obviously takes HP to drive that pump, but if you just grab a drill and run the pump with that while pulling the engine on the Dyno you will lose about 40 HP.

AR

 

[sdwarf36]

Double check the lifter size.......

Thats the other thing that bothered me. Lifter diameter? Roller size? Cam journal diameter?

 

[stitcherbob]

I'm trying to remember where I grabbed that chart from.....but I'm sure some things need updating/correcting

 

[Mike]

It's an interesting theory, but you can't just discount some of the power needed to run the engine. For instance, the oil pump on a Pro Stock engine is driven by a belt off the crank snout. Now it obviously takes HP to drive that pump, but if you just grab a drill and run the pump with that while pulling the engine on the Dyno you will lose about 40 HP.

AR

I'm not sure what you are saying here Alan. Losing hp where? How? By doing what you stated, you should gain power.

 

[Nick Name]

years ago I was down at KB's shop in Lake Forest. They had a blower dyno. I could swear they told me it took more that 1000 hp to turn the blower at max RPM.

 

[sdwarf36]

I'm not sure what you are saying here Alan. Losing hp where? How? By doing what you stated, you should gain power.

A dry sump also acts as a vacuum pump-making negative pressure in the pan. It helps with ring seal and oil windage.

 

[.]

A dry sump also acts as a vacuum pump-making negative pressure in the pan. It helps with ring seal and oil windage.

Yes, but it's still being spun. The pump doesn't know if the engine or a drill is turning it.

 

[.]

years ago I was down at KB's shop in Lake Forest. They had a blower dyno. I could swear they told me it took more that 1000 hp to turn the blower at max RPM.

Mike Kloeber and Norm Drazy have both told me the same thing.