Competition 11.36 @ 120, #2 only and runs clean

[gitchesum]

MDW just called from the track.



Ran a 11. 23, but I didn't get the MPH.



No modifications to the truck since the last runs.

 

[JLackman]

A little history for your thinking. Enjoy



The word horsepower was introduced by James Watt, the inventor of the steam engine in about 1775. Watt learned that "a strong horse could lift 150 pounds a height of 220 feet in 1 minute. " One horsepower is also commonly expressed as 550 pounds one foot in one second or 33,000 pounds one foot in one minute. These are just different ways of saying the same thing. Notice these definitions includes force (pounds), distance (feet), and time, (minute, second). A horse could hold weight in a static position but this would not be considered horsepower, it would be similar to what we call torque. Adding time and distance to a static force (or to torque) results in horsepower. RPM, revolutions (distance) per minute (time), is today's equivalent of time and distance. Back to horses, imagine a horse raising coal out of a coal mine. A horse exerting one horsepower could raise 550 pounds of coal one foot every second.



Here is an example of another way horsepower could be directly measured. Say you have a horse hitched to a plow. In the hitch is a spring scale (like a fish scale). The horse pulls the plow one foot every second and you see 550 pounds on the scale. That horse would be generating one horsepower.



We see horsepower can be directly measured. However there is a problem directly measuring horsepower of modern day internal combustion engines because they produce rotary motion not linear motion, and unless the engine is geared down, the speed at which they do work (time and distance or RPM) is too great for practical direct measurement of horsepower. It seems logical then that the solution was to directly measure torque (rotational force eventually expressed in pounds at one foot radius) and RPM (time and distance, i. e. distance in circumference at the one foot radius) and from these calculate horsepower. Torque and RPM are easily measured directly. Early dynamometers used a brake device to load the engine. A torque arm was attached to this brake's stator. The brake's rotor was coupled to the engine's crankshaft. A spring scale or other measuring device connected the torque arm to the stationary fixture holding the engine and brake. During a test the brake's application loaded the engine. Torque and engine rpm were observed and recorded. Click here for a description of how this happens on our dyno.



On modern day dynamometers horsepower is a calculated value. It's important to remember the dyno measures torque and rpm and then from these calculates horsepower. On the dyno it takes more water flow to the water brake to increase the load on the engine being tested. As the test engine's torque rises more water flow is needed. As the test engine's torque drops less water flow is needed. The dyno's water brake does not respond to Horsepower. Major adjustments to water flow are needed as an engine crosses its torque peak but none are needed as it crosses its horsepower peak. In other words the water flow to the brake during a dyno test follows the engines torque curve and not its horsepower curve. Torque is what twists the tire, prop, or pump. Horsepower helps us understand an amount or quantity of torque. (Torque + time and distance)



Now if we are measuring torque and RPM how can we calculate horsepower? Where does the equation HP=TORQUE * RPM / 5252 come from? We will use Watts observation of one horsepower as 150 pounds, 220 feet in one minute. First we need express 150 pounds of force as foot pounds torque.



Pretend the force of 150 pounds is "applied" tangentially to a one foot radius circle. This would be 150 foot pounds torque.

Next we need to express 220 feet in one minute as RPM.



The circumference of a one foot radius circle is 6. 283186 feet. ft. (Pi x diameter 3. 141593 * 2 feet)

The distance of 220 feet, divided by 6. 283185 feet, gives us a RPM of 35. 014.

We are then talking about 150 pounds of force (150 foot pounds torque), 35 RPM, and one horsepower.



Constant (X) = 150 ft. lbs. * 35. 014 RPM / 1hp



35. 014 * 150 / 1 = 5252. 1



5252 is the constant.



So then hp = torque * RPM / 5252

Don't read too much into what you find on the internet! :-laf



The problem is that torque can be a static force. As soon as there is time and movement added to torque it is horsepower.



The only reason engine dynos measure torque is because there is no practical way to measure crankshaft horspower directly. When I calibrate the torque load cell on my dyno I load an three foot long arm with certified weights. 200 lbs of wieght on that arm three feet off the crankshaft centerline shows up on the dyno readout as 600 ft lbs. torque. The horsepower reads zero though because there is no RPM during the calibration.



I read something somewhere recently that cleared up the Hp vs torque argument for me but I can't remember where it was.

 

[JLackman]

For what it's worth here it is;



http://speedtalk.com/forum/viewtopic.php?t=4834&

 

[EMD-Run8]

Exactly!!!!!!!!!!! Horsepower is static. It is what it is. Torque is dynamic and malleable and can be multiplied with gearing. It is in that "dynamic" where our beloved engine is marking its territory and turning heads. Here's a quote from Mr. David Blundell of Lotus Engineering "The easier ride of the big bang (smoother firing order) engines is well-established in MotoGP. The flat torque curve of a diesel would offer the same advantages". Hello?????? Now that would really upset things-----a diesel in a GP bike? And if it spanked everybody like the Audi R10 did, well, we'd have a revolution on our hands wouldn't we? It'd be hysterical!!! If any group of gearheads out there has more disdain for diesels than motorcyclists, please let me know who they are! I know, I am one, and read about it REGULARLY in the motomags. I'm tellin ya------I think Rudy's invention is coming of age and is only now scratching the surface of what it will do in the near future! It's gonna be fun to watch and hopefully (for me) be a part of as well.

 

[JLackman]

Ummm I don't think HP is static, by definition HP includes time and movement, torque doesn't. Torque can be static like torque on a torque wrench. If there is no movement it is just torque, as soon as there is movement there is also HP.



Like a horse hooked up to a plow, if it has 550 lbs tension on its hitch but it's not moving, there is no HP involved, , it is only when the the horse moves the plow that there is measurable HP. And if it moves the plow 1ft/sec with 550 lbs force that is one HP.



I think it is interesting to consider that direct measurement of HP was likely done long before any type of slip dyno brake and torqueXrpm/5252 was ever used. Why do you think the Dillon type dial scales are called dynamometers?

 

[Mundgyver]

Ok can someone explain why HP rules



I want some to show me how High HP without TQ wins a race. On the other hand I find it interesting that Low HP with TQ, scrambles all traditional logic for the those that think HP is the answer. I find it more intriguing that the argument of two vechicles equally weighted put into a pull against each other, the one with the most TQ (Our Beloved Trucks) seem to win over those that boast mor HP.



TQ is key.

 

[Jim Fulmer]

MDW just called from the track.



Ran a 11. 23, but I didn't get the MPH.



No modifications to the truck since the last runs.

Thanks for the update! Sounds like he is just getting better at it all along.



I had thought this thread was going to be lost forever. I definitely lost interest in reading it.



Jim

 

[EMD-Run8]

My point is that hp is set in character. A certain engine in a certain state of tune makes "x" horsepower at a certain rpm. But! It may not necessarily make the same amount of torque as the next engine which happens to be a diesel let's say. Torque is a different animal and is affected by things like what type or design of engine it is, the weight of the rotating assembly, or maybe the flywheel. It can be multiplied by changes in gearing. Horsepower can't. If you have a diesel, a gasser, a gas turbine and an electric motor that all make the same horsepower, they will most definitely have different torque characteristics. I'm saying that TORQUE and how a diesel makes it is what's allowing a car like the Audi R10 to beat cars heads up that are lighter and make more hp. Geez! It revs out at less than 6000! Sorry to get away from drag racing again but the R10 is just such a great example. Just for grins though, the truck that is the subject of this thread weighs what?------6000 lbs or so? If this truck had a big block in it that made the same amount of hp as the Cummins in it, would it run identical, slower or faster 1/4's?

 

[Mundgyver]

I'm pretty sure it would be slower as it would not make the TQ required. There is no doubt that it takes both to make the grade, but out of the two the only one that allows us to pull the loads with the economey that we get and embarrase a simlar HP V-8 Diesel, is the TQ that the little I-6 puts to the ground. This might be a good argument to send into mythbuster. Hmmm Maybe I will do that before I turn in tonight.

 

[Jim Fulmer]

I had thought this thread was going to be lost forever. I definitely lost interest in reading it.

Hint, Hint.

 

[JLackman]

Torque can exist without HP but HP cannot exist without torque. They really cannot be separated in a discussion on IC engines.



Here is an idea; Set up a rolling dyno, a chassis (sled puller??) in which the engine/trans are mounted on bearings on the crankshaft centerline and held from rotating by a torque arm. Set up the torque arm on a load cell X (1ft?) off the crankshaft centerline. That will be your engine torque/hp reading.



Next set up a hitch on this rolling chassis dyno with a load cell in it. Feed the force signal into the data acquisition along with real time speed and distance. This will be your direct HP.



Pull a load up a long steep hill to compare, in every gear and again and again.



Knock yourself out with the data.



Say the rolling chassis has a auto trans. Your speed is zero, you are holding the load on the hill by slipping the converter. The engine will be putting out both HP and torque (it has torque, speed and distance). The hitch readout will show zero HP since it has LBS. force but zero speed/distance. In this case what is torque?



Here's a question, say you have a gas engine 350hp @ 5000 RPM and one with a diesel 350HP @ 2100 RPM.



Wheel speed is 60MPH the gas engine is at 5000 RPM the diesel is at 2100 RPM, both are running at WOT.



Would the rear wheel torque be the same?

 

[JLackman]

I have a spread sheet that I set up to calculate real wheel torque and cleaned it up a bit to answer the question, it is attached.



Shoot, it will not attach.

 

[EMD-Run8]

Well, we've apparently lost Mr. Fulmer's interest. I apologize sir, I wasn't aware it was required reading.

 

[Jim Fulmer]

Well, we've apparently lost Mr. Fulmer's interest. I apologize sir, I wasn't aware it was required reading.

See I started to go past it. I look at it just to see if there is any info on it!



Please don't call me Mr. Fulmer or Sir... ... dang I'm not that old



Jim

 

[JLackman]

The tire circumference is from our pickup.



350HP @ 5000 RPM = 368TQ @ 5000 RPM at 60 MPH and WOT

350HP @ 2100 RPM = 875TQ @ 2100 RPM at 60 MPH and WOT



Will the rear wheel torque be the same?



Here is the spreadsheet with the answer;



http://www.revsearch.com/gasvsdieselrear wheeltorque.xls

 

[EMD-Run8]

Yeah, I'm not very good at making my point about it. If I'd been building and racing engines for years, I'm sure I could explain it easier. I'm going more off of observations and impressions I've made/had over the years. Several others on the thread explained it much simpler and better than I. I guess the point is obvious really. Oh, I promise not to use "Mr. " or "sir" again.

 

[RailroadJim]

Went to the track sunday and MDW hooked real good, burned off an 11. 23 and still clean, looks like it's got more in it.

 

[JVolpe]

RailroadJim



What did your black beast run???

 

[RailroadJim]

I didn't run mine since i was the designated chase vehicle, still in the 17's, i think i'm better at watching drag racing than actually doing it, besides, i'm skeered until i win the lottery and the transmission gets built.

 

[EMD-Run8]

OK now, were lookin' for a sub-11 second on #2 only right? I think you can do it.