Check this out to read about horsepower.

http://auto.howstuffworks.com/horsepower1.htm

 

One thing they didn't stress enough is that the faster an engine turns, the more HP it can make. The faster you turn an engine, the less torque you need to make a given HP. To make 500 HP at 3500 RPM in a CTD, we have to generate 750 ftlb of torque at 3500 RPM. For some guy in a Mustang to make 500 HP at 7500 RPM, he only needs to make 350 ftlb of torque. This is why it's so tough to make big HP with a diesel, they just don't spin fast enough.

 

A one Horse(Cow)power truck.

 

Looks more like a 1 ox-power truck to me.

 

Who designed that truck and motor combo...Who would ever put the driver directly in back of the exhuast!!!!Hope doesn't try to smoke someone!!!!!

 

Cool concept. A truck that makes it's own bio-diesel!

 

I think some on here may argue with you on that point.

 

So please prove this to me

 

Boy I wish someone would explain all of this to me. Since when does it matter if it is a gasser or diesel the fomula is the same. I guess maybe take the CtD out of a Ram and drop a mustang engine in it then I could get 500 ponies. What then would I have to do to tow the boat ? put the CTD in the mustang Seriously though that Motor must have one heck of a power band to be generating 350 ft lbs of torque @ 7500 rrrrs (power band )

 

Which statement are you looking for proof of? The RPMs, torque, and HP relationship?

HP = Torque x RPM/5252

As you can see, HP is purely a function of torque, and RPM. The faster an engine turns over, the less torque it needs to make high horsepower. Rice rockets can quickly climb into the 350HP - 400HP area simply due to their high redlines.

As for the second statement about being easier to make high horsepower with a gasser easier, I would also tend to agree with that to a point. It simply depends on how much horsepower we're talking about. We can bolt on 4 - 500 HP on a diesel without any problems whatsoever. Its pretty tough to do that with a gasser and have it actually survive. BUT, once we get past the 500 range, the engine needs to be tore into and we need to start replacing things. And, unlike the gassers that have some RPMs to play with, no-one has managed to get a diesel to 1000 HP yet.

Rod

 

Prove what? The formula for HP is:
Do the math. The fastest we can safely turn a Cummins is 4,000 RPM, so our HP number is always going to be lower than our torque number. You can have a 3 liter engine spinning at 18,000 RPM make 1,000 HP (F1 car), but the thing is only making 291 ftlb at that point. Care to tow with that? HP is a math equation, torque is what does the work of hauling the 7,000 pound truck around.

 

I know the formula, but I want you to prove it is hard to make big horsepower with a Diesel..............

 

So what HP numbers are you talking about? Streetable? Strip? What is your definition of hard? You're asking for proof of something without giving any kind of yardstick to measure against.

I'll take a crack at it though:

500 HP - Relatively simple in comparison to a gasser. Fueling box, good turbo, good injectors, fuel system, exhaust, air. You won't need to touch the internals at all. Its high streetable horsepower, but its peanuts in the grand scheme of things.

700 HP - Complexity would be similar to getting a gasser to this point. Twins, o-ringing, cam, injectors, fueling box, fuel system, exhaust, air. Streetability of the diesel is going to be better, but not by much.

800 HP - A real pregnant dog. Its easier to get 800 HP out of a gasser by this point. But we're still not even getting close to true high HP in the grand scheme of things.

900 HP - Thus far, no-one in the diesel industry has gotten this power level with #2. Gassers have made it here on straight gas. So I'd have to say its easier to make horsepower with the gasser by this point. But in the grand scheme of things, 900 HP is still peanuts.

Until someone figgers out how to build a diesel that can rev to 8 or 9000 RPM and hold up, we'll never see the monster horsepower that gas engines are capable of. I'm not sure if this is the proof you need, however it is simply a fact. We need RPMs, and we need lots of them. And right now, no-one has figgered out how to get these RPMs and still maintain engine integrity.

Rod

 

I want to contradict the assumption that torque makes your truck tow good.

If we'd take an engine that had a tenth of the torque at 10x the rpm we see the same hp. Necessarily we'll need a different rear end like a 35.5:1 instead of a 3.55:1. Then we'd see the same torque on the rear wheels. and assuming the same size of the wheels the same pull of the wheel. Adn this pull is what makes the vehicle move. The most interesting value is the curve of horsepower over vehicle speed. If you compare this curve with the power consumption over speed you see the reserves (if any) the vehicle has for a given speed. These reserves can be used to accelerate.
The smaller the width of the powerband the more different ratios (speeds) you need. An 18wheeler has comparatively low power to the weight and air drag it has to overcome. It has lots of speeds to keep the engine ticking around peak hp.
The only downside is that manualy sorting this many gears is called work ( truck drivers get paid for it)

As for the impossibility to make big hp with a diesel: First of all there are some diesels breaking the 100 000 hp barrier (OK maybe you did mean pickup-truck diesels)
See this one http://www.bath.ac.uk/~ccsshb/12cyl/

On the other hand I don't think that the comparison is that fair- AFAIK the race gassers do get different crankshafts, pushrods etc to hold the higher rpm. I don't know what would give first in a Cummins at high revs, but over here there are lots of race and rally cars that are diesel powered. These go up to 300-330 hp with 1.9l to 2l turbodiesels. They deliver peak hp around 7k rpm. (and they do still remain driveable)

Just my 2c

AlpineRAM

 

A gasser is advertised as 350 HP and 350 torque, at 8,000 rpm.

A Diesel is advertised at 350 HP and 700 torque, at 3,000 rpm.

That's double the torque for the same horsepower, at half the rpm.

(just figures for argument)


What is "big horsepower"?

500?
700?
1,000?


I'd rather have an engine that has double the torque for the same horsepower, at slower rpm.

That will get you going up the hill.


phox