How Do They Do That?

[Rockfrog]

With those little 4 bangers they spin them past 16,000rpm (some of them spin that in stock form), then add turbo/supercharger and shot or 12 of nitrous ... in essence sacrificing engine life for fun. There have been a few factory 800+hp motors produced over the years ... the Ford RS200 had (in one form) an 850hp 4 (can't remember if they used the 1.8 or 2.0 for that) ... but after each race it was pretty much burned out and required full rebuild.

 

take that 1000HP motor and it's likely only pushing 260 ft-lbs of torque at peak .... the work like a 2 stroke, not a lot down low rpm, but they pull off the top end. As the curve climbs torque actually drops past the 5252rpm mark (also at which point HP and torque are equal values)

 

The 2.5L is internally similar to the 4.0L so their limitations are equal. It's going to need to breathe ... alot more than the stock head is capable of for 1000hp. There are supercharger and turbo kits available for the AMC 4 (well there used to be at least, if not still). But whether the stock internals would handle spinning upwards of 12-16000 rpm is another issue all together. Getting 250hp from one is doable fairly easily I would imagine but once you reach the limits of the stock engine .... spinning it faster is the only other solution ... The AMC designs were tractor-esque more than race inspired.

[Rockfrog]

http://www.thecarconnection.com/tips-article/1004325_gm-prods-ecotec-to-1000-hp

 

found this on the GM motor mentioned

[mvusse]

 

GM developed and raced a 1000hp ecotech Sunfire 10 years ago. Stock block, mostly stock head, destroked to 2.0l displacement, all custom internals and 40lbs of boost.

And what cost? I never heard that. I do recall that expirement and other similar versions as the attempt a sport compact class in NHRA. The now decades old claim that hipo 4-bangers would lead to the abandonment of v8 pro-stock & other v8 drag cars was entirely wrong and the compact class using such engines died quickly. Right or wrong most every form of motor racing in America is still dominated by V8's. 

 

Don't know. But every part produced for that engine was given a GM part number so you can order it.

[Oyaji]

 

I think you  would benefit from a review of the definitions of power and torque. Though I doubt you would agree, pretty much everything you had to say was in support of my first post in this thread.

.

You asked "How do you "twist" something without power?" Here is an example for you: clamp the square end of  a spring-beam torque wrench into a bench vise. Pull on the handle, and watch the pointer on the torque scale rise. You are generating torque, but doing no work because you have not moved anything, nor  are you generating  power, because power is a measure of how fast work is done. Another example: sitting on the lowered tailgate of your MJ generates torque about the tailgate hinge equal to your weight times the distance you sit from the hinge, but  doing  so    does no work nor generates  any power at all.

.

Horsepower and torque are related, just as I said in more detail in my first post, but torque alone does nothing at all. 

I am pretty certain that torque wrenches, including the beam type, do move as you apply torque in order for the pointer to move along the scale for measurement don't they? Even you say "watch the pointer...rise..." which clearly indicates movement, however small, as the pointer is directly connected to the wrench shaft.  

.

OK then, since you insist, toss the beam torque wrench in my example and substitute a preset "dial-in limit" torque wrench. You will not see the pointer move, but you will feel the "clik" when you exceed the preset dialed-in torque threshold (whatever the setting), so you know you are generating torque without movement, work, and power.

.

Like the example better now? :)   

[Keyav8r]

Actually, on a flex beam torque wrench the "needle" doesn't move unless the fastener is turning, in which case the whole wrench is moving. The flex beam (handle) deflects more as the torque required to turn the fastener increases, thereby moving the scale that the unflexed needle registers against. Just another technical point to argue about.

Foot-pounds of torque is a measurement of force exerted. You could argue that exerted force is a form of power or argue that torque and HP are entirely separate and un-related (they are related), but none of this directly addresses the OP's question (as I understand his question).

I believe he is asking how it is physically/mechanically accomplished.

[ftpiercecracker1]

, but none of this directly addresses the OP's question (as I understand his question).

I believe he is asking how it is physically/mechanically accomplished.

 

 

THANK YOU!!  

[Incommando]

 

 

I think you  would benefit from a review of the definitions of power and torque. Though I doubt you would agree, pretty much everything you had to say was in support of my first post in this thread.

.

You asked "How do you "twist" something without power?" Here is an example for you: clamp the square end of  a spring-beam torque wrench into a bench vise. Pull on the handle, and watch the pointer on the torque scale rise. You are generating torque, but doing no work because you have not moved anything, nor  are you generating  power, because power is a measure of how fast work is done. Another example: sitting on the lowered tailgate of your MJ generates torque about the tailgate hinge equal to your weight times the distance you sit from the hinge, but  doing  so    does no work nor generates  any power at all.

.

Horsepower and torque are related, just as I said in more detail in my first post, but torque alone does nothing at all. 

I am pretty certain that torque wrenches, including the beam type, do move as you apply torque in order for the pointer to move along the scale for measurement don't they? Even you say "watch the pointer...rise..." which clearly indicates movement, however small, as the pointer is directly connected to the wrench shaft.  

.

OK then, since you insist, toss the beam torque wrench in my example and substitute a preset "dial-in limit" torque wrench. You will not see the pointer move, but you will feel the "clik" when you exceed the preset dialed-in torque threshold (whatever the setting), so you know you are generating torque without movement, work, and power.

.

Like the example better now? :)   

Not really as how do you get it to click if it doesn't move? Deflection is also movement..... Just poking the bear and I don't think we will get anywhere so I will drop this  :thumbsup: I actually did make a suggestion as to a possible resource source by looking at a different group like drag racers. But as this topic is entirely an exercise in what-ifs & make-believe due to "no budget limitations" and other pre-set perimeters it is not like anyone is messing up someone's "help my MJ won't start" post. Thus it was placed in The Pub and not Tech, yes? 

[gogmorgo]

Deflection is movement, yes, but the pivot point itself isn't turning. Torque is just pushing on something in such a way as to make it spin. Higher torque is pushing harder. If the thing you're trying to spin resists the spinning, then you won't necessarily get movement, but if the resistance is less than the torque, then things move. When you're torquing down a head bolt, you initially torque it to something like 25 ft-lbs. Then the last torque stage is something like 120ft-lbs. You have to push on the wrench a lot harder to apply the 120ft-lbs to the bolt, but are you really turning it any more than you did at 25 ft-lbs? Not really, no. You're just turning it harder, i.e. with more force.

 

Horsepower is a measurement based on how hard the engine is pushing and how quickly it's turning. So you can make a whole bunch of horsepower by pushing a little and spinning really quickly, or you can make the exact same amount of horsepower by pushing really hard and turning really slowly. If you can push really hard and turn really quickly, then you'll make lots of horsepower. :). As a bit of an example of that, the engine in the racecar sitting right behind my computer makes only 35 ft-lbs, but it makes 90 hp because it spins to 15,000rpm. In comparison, the engine in my buddie's Fiero makes something like 130 ft-lbs, but still only makes 90hp because it's only spinning at 4,000 rpm. It's kinda like 3x8=24 but you can also get 24 by doing 6x4=24. If somehow you could get that Iron Duke spinning itself at 15,000 rpm and still making 130 ft-lbs, you'd be looking at roughly 370hp. But I wouldn't want to be anywhere near that engine spinning that fast for fear of my life... Conversely, assuming we're still making 35 ft-lbs in our racecar at 4,000 rpm, we'd be making something like 25 hp.

 

So to sum it up:

Torque is how hard you push.

Horsepower is a measurement of both how hard and how quickly you push.

 

 

As an aside, you can increase torque output with lower gears. With low enough gears, you could have that Fiat 500 you mentioned moving the same amount as the older CTD's. You reduce the gears and increase the wheel torque compared to engine torque while keeping the wheel horsepower the same as engine horsepower (minus any losses due to drivetrain inefficiencies). But when the wheel torque goes up, the wheel speed must go down because the power output is constant. So you won't be going anywhere near as fast as you were with the CTD. Going back to our racecar from the example above, even though it's only making 35 ft-lbs at the crank, we've got the original motorcycle transmission attached to the engine and then we're running a 5:1 reduction between there and the rear end. Between that and the fact that the thing weighs all of 600 lbs with a driver in it, we can still hit 60 mph in well under 4 seconds with only 35 ft-lbs of torque.

[Oyaji]

^

Well-said, and good examples too!

.

We should move on to the OP's question of how to get crazy power levels out of an  AMC 2.5  4-banger. He ain't gonna like the answer, because it is so technically difficult that it would be impractically expensive, but let's go there just for fun. Everybody should chime in, so I'll just throw out a  starting point and let you guys find solutions, no matter how bizarre or expensive.

.

Let's say we want to make 1,000 hp at 10,000 rpm - what would it take for us to build  that engine? Start with  figuring out the thrust per stroke, then consider the block - look at the main bearing journal webbing - is it sufficient to handle the thrust? How about the crankshaft? Pistons and rods? What do we need to hold the head on  with to keep it from separating from the block?            

[Incommando]

The other variable is how long do you want to make that 1,000 hp? Enough "power adders" could do it to many engines...briefly.

[ftpiercecracker1]

Deflection is movement, yes, but the pivot point itself isn't turning. Torque is just pushing on something in such a way as to make it spin. Higher torque is pushing harder. If the thing you're trying to spin resists the spinning, then you won't necessarily get movement, but if the resistance is less than the torque, then things move. When you're torquing down a head bolt, you initially torque it to something like 25 ft-lbs. Then the last torque stage is something like 120ft-lbs. You have to push on the wrench a lot harder to apply the 120ft-lbs to the bolt, but are you really turning it any more than you did at 25 ft-lbs? Not really, no. You're just turning it harder, i.e. with more force.

 

Horsepower is a measurement based on how hard the engine is pushing and how quickly it's turning. So you can make a whole bunch of horsepower by pushing a little and spinning really quickly, or you can make the exact same amount of horsepower by pushing really hard and turning really slowly. If you can push really hard and turn really quickly, then you'll make lots of horsepower. :). As a bit of an example of that, the engine in the racecar sitting right behind my computer makes only 35 ft-lbs, but it makes 90 hp because it spins to 15,000rpm. In comparison, the engine in my buddie's Fiero makes something like 130 ft-lbs, but still only makes 90hp because it's only spinning at 4,000 rpm. It's kinda like 3x8=24 but you can also get 24 by doing 6x4=24. If somehow you could get that Iron Duke spinning itself at 15,000 rpm and still making 130 ft-lbs, you'd be looking at roughly 370hp. But I wouldn't want to be anywhere near that engine spinning that fast for fear of my life... Conversely, assuming we're still making 35 ft-lbs in our racecar at 4,000 rpm, we'd be making something like 25 hp.

 

So to sum it up:

Torque is how hard you push.

Horsepower is a measurement of both how hard and how quickly you push.

 

 

As an aside, you can increase torque output with lower gears. With low enough gears, you could have that Fiat 500 you mentioned moving the same amount as the older CTD's. You reduce the gears and increase the wheel torque compared to engine torque while keeping the wheel horsepower the same as engine horsepower (minus any losses due to drivetrain inefficiencies). But when the wheel torque goes up, the wheel speed must go down because the power output is constant. So you won't be going anywhere near as fast as you were with the CTD. Going back to our racecar from the example above, even though it's only making 35 ft-lbs at the crank, we've got the original motorcycle transmission attached to the engine and then we're running a 5:1 reduction between there and the rear end. Between that and the fact that the thing weighs all of 600 lbs with a driver in it, we can still hit 60 mph in well under 4 seconds with only 35 ft-lbs of torque.

 

 

Very well said indeed.  :clapping:

[ftpiercecracker1]

^

Well-said, and good examples too!

.

We should move on to the OP's question of how to get crazy power levels out of an  AMC 2.5  4-banger. He ain't gonna like the answer, because it is so technically difficult that it would be impractically expensive, but let's go there just for fun. Everybody should chime in, so I'll just throw out a  starting point and let you guys find solutions, no matter how bizarre or expensive.

.

Let's say we want to make 1,000 hp at 10,000 rpm - what would it take for us to build  that engine? Start with  figuring out the thrust per stroke, then consider the block - look at the main bearing journal webbing - is it sufficient to handle the thrust? How about the crankshaft? Pistons and rods? What do we need to hold the head on  with to keep it from separating from the block?            

 

 

No answer would be the only answer that would disappointment to me.  I don't have a 2.5, i only used it for familarity sake.

[jpnjim]

Think of one end of the extreme being a tractor engine

and the other being a motorcycle engine.

 

Tractors have big slow moving engines with long strokes and a slow valve train (pushrods or even valve in block flathead)

Motorcycles have short stroke fast moving engines with fast, efficient ohc valvetrain & very efficient combustion chambers,

some with 12:1+ compression ratio stock.

 

Our Jeep 2.5's are closer to the tractor side of things,

the Hondas and Zetecs of the world are closer to the motorcycle end of the scale.

[jpnjim]

This phone sucks at posting, so I had to cut it short,

but even adding a cross flow head, or forced induction,

our tractor engines will never be as efficient as a little, simple 2.0l ohv made to rev.

 

The old Iron Duke engines were slightly better at impersonating a mc engine,

shorter stroke,, cross flow head, etc,

but its still tough to untractor a tractor engine :)

[jpnjim]

Last post,

you can't put a motorcycle engine in a tractor either,

a 150 HP superbike engine will fail in place of a 60 horse tractor engine just as badly as the 60HP engine fails in the superbike.

 

And you can't modify the mc engine to suit a tractor, just like modifying the tractor engine still = a crappy mc engine.

[onlyinajeep726]

I bet I can really confuse things. If you're not familiar with electricity don't bother reading this. Think of horse power, HP as voltage E. Think of torque as Current or amperage I. The voltage provides the potential to do work but does nothing itself. The current does the work but it needs a potential, voltage to determine how much work it can do. The higher the potential, E, the more work the current, I, can do.Or something like that.

 

Makes sense to me. :thumbsup: But, I have electrical experience and all that jazz.