How performance car parts influence torque vs horsepower?

In summary, the conversation revolved around the relationship between torque and horsepower in engines, with a focus on how the design and structure of engines can affect their power and torque output. The conversation also touched on the importance of understanding the physics behind engines and the differences between performance engines and mass-produced engines. The participants recommended a book for further reading and suggested the OP to post more specific questions to avoid confusion in the discussion.
  • #1
hondaman520
33
0
I am currently majoring in mechanical engineering at Texas A&M after having completed my associates degree in automotive technology (4.0gpa) while i'v been fixing cars at Firestone Autocare. Its odd that i rarely find anyone who knows a thing about the physics of energy efficiency and the relationship between torque and horsepower in an every-day motor vehicle.

Now, i know what your thinking! we could spend pages discussing horsepower vs torque proportions and how they vary depending on engine RPM SO ON AND SO FORTH! But that's what the weekend track racers and the gear heads want to know.

ME, the engineer is curious about how parts/structure OF THE ENGINE (for example: camshaft lobe profile, valve timing/lift, stroke, bore, etc...) have an affect on power and torque values. It is interesting to think about especially when noticing the differences between output values of diesels vs gasoline powered engines seeing as the torque in diesels triumphs horsepower, and vise versa in modern gas engines.

I have a very strong knowledge of the parts that come together in the right sequence to provide efficient combustion, but when it comes to physical factors that can give an engine a lot more low end torque as opposed to high end horsepower, it seems to be a bit more technical.

PLEASE, ENLIGHTEN ME. i am interested to hear from anyone into this kind of stuff.
 
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  • #2
Power = Torque * RPM

It is as simple as that. I’ve worked power transmission systems on boats, ships, airplanes, locomotives, jets, heavy equipment, and many more systems. I’ve also spent thousands of hours in the shops with the mechanics. Every place I’ve been, the mechanics will get into strange discussions concerning the advantages of high or low toque, all based upon a fundamental ignorance of the physics involved. When that happens, just refer to the equation above and you will not be confused.

The torque put out by the engine does not matter at all. What matters is how much power the engine puts out, and what percentage of that power you are able to transmit to your load. High torque at the engine compared to low torque only changes the gear ratios in between the engine and the load. If you have designed your power transmission correctly, the load won’t know the difference between a high torque engine and a low torque engine.

In general, a low toque engine can come up to power more quickly than a high torque engine. That is not always true, but often is. In that case, you have a dynamic rate of change difference, but steady state will be exactly the same.

As for the design of the engine, high torque increases the loads in all parts of the engine, so it is bigger and heavier. It will have a less favorable power to weight ratio. Consider a diesel, a gasoline engine, and a gas turbine. The only real difference for power transmission concerns is that we have progressed from a slow shaft speed (high torque) to a very high shaft speed (low torque). Assume that all three engines put out the same power. The diesel will be very heavy, the gasoline engine will be much lighter, and the gas turbine will be a small fraction of that. A 100 hp gas turbine at 100,000 rpm would be very small and light.
 
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  • #3
Welcome..this forum is a gold mind for inquiring minds ...please look at these posts
use your search function above...some real top notch people have posted great information


volumetric efficiency Mar14-09, 05:36 AM


Horsepower - Please help - Confused! Feb14-09, 05:36 AM


Torque vs RPM Mar28-09, 07:51 AM


Why Does the Torque Curve Drop Off at Low RPM in a Typical Piston Engine? Jul11-08, 01:51 AM



Engine size/type (ie. 2L inline-4) and fuel consumption Jun8-09, 08:01 AM

Expansion ratio of burned Fuel Jul23-09, 02:50 PM


piston size and proportionate forces Oct28-09, 07:17 PM

Efficiency with a combustion engine Oct26-09, 10:05 PM

Pushing the piston. Nov22-09, 08:29 PM


Internal Combustion Piston Lubrication Apr24-11, 09:56 PM

gas pressure in internal combustion gasoline engine Nov22-09, 02:16 PM
 
  • #4
The torque put out by the engine does not matter at all

This is such a disgustingly gross over simplification, for people who have no part of the design or analysis.

People who like a quck answer to what my engine can do use the left hand side of the power equation. Design requires the right hand side.

An engine sticking out 1000Nm @ 300rpm.
An engine stickign out 1Nm @ 300000rpm.

Same ability to do work, but you can't use the same box for both.
ME, the engineer is curious about how parts/structure OF THE ENGINE (for example: camshaft lobe profile, valve timing/lift, stroke, bore, etc...) have an affect on power and torque values.

Simply:
More air intake allowing
More fuel to be burned making
More power.

For performance engines, everything is designed to get as much air fuel mix burned as possible.Less Simply:
https://www.amazon.com/dp/007028637X/?tag=pfamazon01-20

If you are going into engineering (re engines) and don't have this book, get it.
It's as valuable as Roarks or Machinery's.OP you may want to post a more specific question, narrowing the scope for the thread.

It may be worth starting multiple threads on different aspects of the things you want to know. Otherwise it'll quickly become a torque vs power thread and become a horrid mess.
 
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  • #5
THANK YOU EVERYONE for the replies, i never get bored of hearing about these kinds of things.

I think some might be confused as to what the context of my question was cause lol, no one wants to start an argument between the benefits of torque and horsepower depending on the application.

I was more interested in how the mechanical structure, the ARCHITECTURE of engines and their internals, the way they are shaped, the durability them, TAKING IN ACCOUNT the amount of fuel/air/timing can be transmitted reasonably in modern applications of mass produced machines these days. It is understood that more air+fuel at 14.7/1 ratio you can get in and out of an engine, the more work will be done. I don't find electronics have that much of a say in this, because, with the right sensor placement, electronics sort of perform their function at an optimum level these days, that's more of another topic which will probably grow in the future (ie Variable cam timing/variable compression ratio etc.) It seems this thread is sort of jumping around cause its hard to decide what my perticular question is. I guess it really is my lack of knowledge of the physical characteristics of the combustion engine itself.

Pkruse, you had a real good point about the variations of load and weight on the engine parts, so your saying diesels would require bigger and more durable parts just because of the mechanical load itself whereas turbine engines can use much smaller parts due to the smaller load (taking in account the way they perform the same amount of work is totally different. Never really thought about that.

It looks almost obvious as the more displacement used to turn a crankshaft: the more torque an engine would have, so bigger cylinders is a torque affecting variable. I wasn't sure about compression, because I know compression is wanted as much as possible in order to burn ALL the fuel in the cylinder, and diesels can withstand more compression due to their durability. Port diameter/aerodynamics and inlet outlet size is a major variable of torque at low end vs power at high end, (usually changing these factors significantly sacrifice high end horsepower to benefit the low end torque, or silencing affect- depending on the application.)

BTW thanks RANGER MIKE for listing all those references. this is seriously a gold mine, and I'm probably gunna link this to my local car enthusiast forum, those guys would love this stuff.
 
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  • #6
hondaman520 said:
Pkruse, you had a real good point about the variations of load and weight on the engine parts, so your saying diesels would require bigger and more durable parts just because of the mechanical load itself. Never really thought about that.

High torque engines have high mechanical loads. But high revving engines have high inertia loads.

If you imagine, a piston has to slow to zero at TDC. The faster the RPM, the faster it needs to decelerate from it's peak speed. high accelerations = high forces.

At medium to high RPM, the inertia of the components acutally becomes the dominant loading and the gas force from the piston becomes less important.

hondaman520 said:
Port diameter/aerodynamics and inlet outlet size is a major variable of torque at low end vs power at high end, (usually changing these factors significantly sacrifice high end horsepower to benefit the low end torque, or silencing affect- depending on the application.)

This is again all about getting air into the engine. You can tune a pump to work is a specific rev range.

eg.
Small valves produce better flow at low RPM. But obvious have a limited capacity for flow.
Large valves produce poor flow at low RPM but have higher capacity.

This is why race engines sound and drive awfully at low rpm. They are designed to be at their peak at high RPM.
 
  • #7
Sorry, Chris, I need to step in here; you're describing how port size can affect the torque curve, not valve size. Generally for a given port size, the larger the valve the higher the flow (curtain area). Once the port is the main restriction the valve size doesn't matter.
 
  • #8
I
mender said:
Sorry, Chris, I need to step in here; you're describing how port size can affect the torque curve, not valve size. Generally for a given port size, the larger the valve the higher the flow (curtain area). Once the port is the main restriction the valve size doesn't mWeatter.

Good to see you spotted the deliberate mistake. I meant port.

ive been using the wrong word a lot lately, its getting embarassing now.
 
  • #9
Chris: It really is as simple as I stated in my last note. If you want to increase the power output of your engine, then you have only two choices: increase torque and/or increase rpm.

Increasing rpm has all the standard options: pay attention to the aerodynamics of your intake and exhaust flow paths, balance everything with as much precision as possible, replace stock parts with stronger parts, use light weight parts to minimize moving mass, stronger valve springs to prevent float, and all that sort of stuff. You also want to increase the mass flow rate of both your fuel and air, but I’ll talk more about that below.

Increasing torque means increasing how much force the pistons can transmit to the crank. Some of your options are the same. Increase mass flow rate of fuel and air, increase compression ratio. That last one goes with increasing the thermodynamic efficiency of the engine, which has the same effect as increasing fuel and air flow.

Adding a mechanical air pump to the intake will have the same effect as increasing compression ratio, though the two are not the same. I’ve seen diesel engines with compression ratios as low as 10:1, a ratio that no diesel can work at unless you blow in a whole lot of supplemental air.

Remember that increasing the power output of the engine will also increase the waste heat output, so beef up your cooling system.

Putting out much extra hp will increase the loads on everything. In the case of increasing torque, the source of the extra load is obvious. In the case of extra rpm, the source will be dynamic forces from spinning faster. So where ever possible, use stronger components and lubricate them better.

A friend builds up Chevy small blocks to put out nearly 1400 hp. In his application, they only have to last a very few seconds, and sometimes they don’t even do that. He uses a Dodge crank that does two things for him: It is stronger, and it has a longer stroke. (He has to make room for it by grinding parts of the block away.) The longer stroke goes to increasing torque, but he is also spinning it very fast. He also tells me that the steel Dodge crank is much stronger than the original. His pistons and valves are Titanium, and the designs have been optimized to use as little of the material as possible. Very light weight and balanced with precision.

Increasing the combustion pressures may defeat the stock head gasket design, so you may have to do something special to prevent a leak there.

Another option is to increase the energy content of your fuel. Now you are talking about some special racing fuels. They may require changes in the air mixture, or you may decide to supplement the air with more oxygen. I guess the most common source of more oxygen is from nitrous oxide.

Now that you have a more powerful engine, you need take a look at your power transmission. Do you need to change the gear ratios? Can it and its mounts tolerate the increased torque?

How is that for a bunch of random thoughts, rapidly composed?
 
  • #10
BTW: for a really powerful strong engine, start with a spark ignition version of a diesel engine. That gives you a base that is very strong from a structual perspective.
 
  • #11
A great deal of science and physics goes into the design of a gas turbine. (Gas turbines that fly are most frequently called “jet engines.” Those that don’t fly are generally called simply, “gas turbines.” The design is the same, except that the flight version is always optimized for low weight and physical volume.) More sophisticated mechanical engineering goes into a gas turbine than probably any other design, with the possible exception of some space craft. I’ve never seen the reciprocating engine designers borrow science from the gas turbine industry in order to optimize their design, but let’s see if we can do a little bit of that here.

A turbo charger is really just a small and greatly simplified gas turbine, with the reciprocating engine serving as the combustor. A gas turbine has a compressor up front, which feeds air into the combustor, which feeds into the turbine section. In a pure turbojet, the work done is by the mass flow rate of the exhaust gasses pushing the airplane forward. But in most jet engines flying today, the exhaust gas does little or no work. The airplane is propelled either by a conventional propeller (in the case of a turboprop), or by a ducted fan (in the case of a turbofan).

Jet engine design engineers speak of “bypass ratio.” That is the ratio of the air entering the front of the engine divided by the amount of air passing through the gas turbine. The bypass air flows around the engine and blows out the back, providing most of the forward thrust. In the past, 15:1 was considered a high bypass ratio, but Pratt & Whitney is in the process of releasing a new engine with a 49:1 bypass ratio. The higher the number, the more efficient the engine and it is also much quieter. This promises to be a great “game changer” in the aviation world. Fewer parts, cheaper to build, cheaper to maintain, burns less fuel, and you can hold a normal conversation next to one running at full power. All this was made possible by a new gear box that enables the engine to turn a much larger fan at lower speeds. It has taken them 15 years to develop this gear box, after many have failed to do so in the last several decades. This is why I stand by my previous note, that it really is as simple as Power = Torque * RPM. All you have to do is install an appropriate gear box between the engine and the load. That statement was not always true in the past, before the development of much better gear design, but it is true today.

So just like in your car, the power output of the turbine is normally a rotating shaft. In ground applications, that may turn a generator or some other equipment.

About 75% of the power generated by the turbine section is used to turn the compressor. So if the turbine is putting out 1000 hp, only 250 hp is available for the output shaft. It is the same thing with a turbocharger. It is an error to believe that “free” waste energy in the exhaust drives a turbocharger. A TC might boost the power output of the engine by 100 hp, but then it might put a 40 hp load onto the engine. So the net power increase of the engine is only 60 hp. You never get something for nothing in the energy department, and I’m probably being overly optimistic to believe that this hypothetical TC would only consume 40 hp. It probably consumes more.

You can find a great plethora of tutorials and videos of how people have used a standard TC to make their own jet engine, by adding an external combustor to it, normally powered by propane. But it could be powered by any other hydrocarbon fuel. When you see these videos, the first obvious question is of what practical value is it? How can I extract usable power from it? All I have is a very inefficient turbojet that is probably too heavy to fly and too bulky to mount into a real aircraft. So let’s conduct a thought experiment as to how we can use this to increase the power output of a reciprocating internal combustion engine.

How about if we used the exhaust from this homemade jet engine to spin a second turbocharger? They have been doing that for decades with aero derivative engines for peaker units in power plants. A jet engine turns another turbine, which turns the generator. Could we not do the same thing here? What if we used this homemade jet engine to drive a second turbine to pump air into the engine without adding a parasitic load to the reciprocating engine? Now you could get the full 100 hp transmitted to the crankshaft.

I know it would take much more engineering effort to work out the details of how to mount something like this into a real automobile, but does anyone see any holes in the basic concept?
 
  • #12
This thread is diverging rapidly from the point. With increasingly long posts.
we need to break it up into several threads.
A TC might boost the power output of the engine by 100 hp, but then it might put a 40 hp load onto the engine. So the net power increase of the engine is only 60 hp. You never get something for nothing in the energy department, and I’m probably being overly optimistic to believe that this hypothetical TC would only consume 40 hp. It probably consumes more.

Pressure driven turbos cause virtually no load. Back pressure causes losses on the order of 1-2% of engine output.
The figures you are talking about are more like loads seen from superchargers.

The reason why turbocharging is essentially free is they use energy that would otherwise be wasted. It's more energy recapture.

How about if we used the exhaust from this homemade jet engine to spin a second turbocharger? They have been doing that for decades with aero derivative engines for peaker units in power plants. A jet engine turns another turbine, which turns the generator. Could we not do the same thing here?

Turbo compounding is being looked at on cars. It's also being looked at for the next lot of changes of F1 regs. It's interesting beucase the velocty tubines don't cause the backpressure that pressure turbines do.
 
  • #13
Pkruse said:
A friend builds up Chevy small blocks to put out nearly 1400 hp. In his application, they only have to last a very few seconds, and sometimes they don’t even do that. He uses a Dodge crank that does two things for him
Why bother when cranks for SBCs come in every reasonable stroke and are a fraction of the cost of a Dodge crank?

Pkruse said:
His pistons and valves are Titanium, and the designs have been optimized to use as little of the material as possible.
No, pistons for SBCs are not made from titanium.

Better check with your friend, sounds like you've got a few facts mixed up.
 
  • #14
xxChrisxx said:
Good to see you spotted the deliberate mistake. I meant port.
Oho, just seeing if I'm paying attention!

Not that I've ever used the rong tirms or such ...:smile:
 
  • #15
Pkruse said:
Jet engine design engineers speak of “bypass ratio.” That is the ratio of the air entering the front of the engine divided by the amount of air passing through the gas turbine. The bypass air flows around the engine and blows out the back, providing most of the forward thrust. In the past, 15:1 was considered a high bypass ratio, but Pratt & Whitney is in the process of releasing a new engine with a 49:1 bypass ratio.

? The P&W website seems to be stating 9:1 or 12:1 bypass for their geared fans, not 49:1

http://www.pw.utc.com/products/commercial/purepower-pw1000g.asp [Broken] (the "characteristics" tab).
 
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  • #16
AlephZero: They have been testing many versions of these engines for a long time now, and have bragged about being able to produce it in a 49:1 bypass ratio. From a purely engineering perspective, that is a reasonable number. They say that they plan to build the engine in many versions to fit many different aircraft, but that they are starting with the few you saw on their web page. All have under-the-wing space limitations that limit the bypass ratio. But note that the plane with the largest clearance is getting the highest ratio. What we need now is for the aircraft manufacturers to release a design that would accept such an engine. If these first few live up to expectations, I expect that will happen sooner rather than later.

But all this is irrelevant to my main point that we have had great improvements in gear design technology, such that differences in shaft speeds at high power levels are now reasonably addressed in a power transmission design. Axioms concerning limitations that everyone used to assume as true must now all be questioned.
 
  • #17
Mender:

I have no doubt that what you say is true. I also grant that if I were to collect the data required to run a proper engineering analysis, that it would show that the Dodge and Chevy cranes are essentially equal. But it would make no difference to him. His gut says that the Dodge is better. All he knows is that he and his friends have broken Chevy cranks, but they don’t tend to break the Dodge cranks. Purely anecdotal evidence not supported by science. But then I’ve already been told that folks who make cars go fast go more on the gut than on science.

I know what Titanium looks and feels like. I know how a competent engineer would change the design if he were redesigning an aluminum part in Titanium. The price he paid for them was consistent with my experience for low production parts machined with precision out of Titanium. These pistons passed all those tests with me, but the real clincher was when I checked the literature that came with the parts, which said that they were indeed made out of Titanium. Titanium may be very rare for pistons in a SBC, but they are available.
 
  • #18
Chris: I think that perhaps you are more correct than me on the turbochargers. I checked with engineers who design turbo machinery, and I read a masters thesis on the design of turbochargers that I found in the MIT archives. And I evaluated the compressor and turbine maps for a typical automotive TC. They do indeed put a load on the engine, but the number is closer to what you say than my previous estimate of 40%, at least for stock automotive applications.

But I learned something else interesting. The TC will always put a back pressure onto the engine, which is a load. But the trend when the system is correctly engineered is to do other things to reduce back pressure elsewhere. They try to use larger pipes, for example. The net result in a specific application may very well be that the engine has the same or less back pressure than it originally did.

An automotive TC simply does not cost much energy to run because it really does not pump much air, compared to other applications of turbomachinery.
 
  • #19
its late and I've been out on the beerr.

but we all have a differnet breadth of knowledge to bring to this foruim. and that what s makes it so great.
 
  • #20
Isnt this what led to the jet engine ?

In WW2 turbochargers increased mass flow rate to point valves got in the way, and thrust from exhaust became significant? Since the recipcating engine was becoming almost a compressor/heater for the turbo they replaced it with centrifugal compressor and burner cans...

i've read that the air-racer guys run their P-51's at 4 atmospheres... i don't know if that's a lot but sounds like it to me.

old jim
 
  • #21
I find that very interesting, Jim. I wonder where I can learn more about WWII applications. In all the research I've done on the subject, I've seen nothing. Apparently, I'm looking in the wrong places. I know a man who has been designing turbomachinery since WWII, and his mind is still extremely sharp. I've got a meeting scheduled with him next week to talk about some engineering design software he has developed, and to compare it to my feeble attempts to write similar software. I'll see if perhaps he can add something interesting on the subject.
 
  • #22
I hope you bring back some anecdotes.

Dover Press used to have interesting old technology books.
Their "Aircraft Carburetor" book should be in every high school curriculum . Nobody should be helpless when confronted with a gummed up lawnmower or outboard.
Pratt-Whitney puiblished a wonderful "Aircraft Magneto" book, i wonder if it's on their website...

I'll poke around.
 
  • #23
So you want to study the structure of an engine. First off you should be observing your foundation. The cylinder block/ engine block. You will have engines that utilize parent bores or sleeve/liners (mostly diesel mills). Besides the two apparent large reasons we have being used today, a block is a block IMO, doesn't matter who cast or cnc milled it. Look at every area of the block, some have ribs, others are just thick cast etc. What you are really looking at is how the block maintains its shape and rigidity through design while enduring the stresses of operation. You do the same observations with the internal rotating assembly. Other observations you need to consider are your lubrication clearances, gasket thicknesses, engine coolant passages, top end layout (head(s), intake manifold position and layout. The internal dimensions of everything play roles from cooling efficiency (heat transfer) between your oils and coolant, lubrication efficiency, strength to keep distortion at bay (look at fasteners too) and so on. You can build an engine ANY WAY you like, its the hood of the car or truck that limits us from making the most optimum design possible. The engine is a big compromise plainly put.

I wasn't sure about compression, because I know compression is wanted as much as possible in order to burn ALL the fuel in the cylinder, and diesels can withstand more compression due to their durability.

Lets clear this up some. You can use compression for two things I think are worth speaking of, one is obviously producing a ratio large enough to propel the vehicle efficiently. Two, using it only to make as much power as possible without burning completely in a gasser engine. If you can get more torque/power from higher compression and you don't have to worry about a 100% complete burn, without washing your walls, it will make your vehicle fast only IF your suspension can plant the tires. In the diesel's perspective, you have a big difference in combustion characteristics. First, being your fuel, the diesel fuel has more energy to release because of being more dense. Second, you have compression ignition which the lead point (starting of injection) is what you could call diesels version of spark timing. CI engines use less lead reducing work lost to pressure buildup prior to TDC. Depending on the diesel, you will notice the chamber design in the crown of the piston. Same for any gasser mills. I guess what I am saying, compression is not the only factor when attempting to produce a complete, clean efficient burn.

It is understood that more air+fuel at 14.7/1 ratio you can get in and out of an engine, the more work will be done.

Stoichiometric (chemically correct) is a baseline for the perfect burn. Depending on your chamber characteristics and fuel and fuel amount and numerous other variables contribute to a complete burn. Thermal efficiency and combustion management will be what you should read on not only car engines but motorcycle engines from early to modern time. Sir Harry Ricardo, Jim McFarland and Larry Widmer are a few people you should check out.

My advice for you, buy books not just the ones you need for the engineering course but actual performance books. David Vizard has some good ones, Charles Fayette Taylor, Reher-Morrison racing engines and many others. Understanding how engine parts are machined and assembled will give you a good base to start from. Be careful on what you read, there is a great amount of BS out there or its just a big advertisement for the company its involving.

Get an engine, right now still being the cheapest will be a SBC unless your already have an engine in the garage. Take it apart and BUILD it don't just assemble it. If you thoroughly build an engine for a goal you present to yourself you will have learned something. Putting something together is just that. Building something is tayloring it to your preferences on what you want it to be.

The structure of each part of the engine when compiled either produces efficient power or you have junk. Building an engine will teach you a lot on what you are trying to learn.
 
  • #24
Pkruse said:
Mender:
All he knows is that he and his friends have broken Chevy cranks, but they don’t tend to break the Dodge cranks.
They shouldn't be breaking cranks at only 1400 hp; there are cranks out there that will handle 2200+ hp - if they don't rattle the engine.

Heck, even a stock cast crank (and block and rods and pistons and rings and bearings!) in a 4.8 LS engine can survive over 1200 hp.
http://www.hotrod.com/techarticles/hrdp_1109_stock_gm_ls_engine_big_bang_theory/
Pkruse said:
Mender:
These pistons passed all those tests with me, but the real clincher was when I checked the literature that came with the parts, which said that they were indeed made out of Titanium. Titanium may be very rare for pistons in a SBC, but they are available.
I stand (well, sit, actually) corrected.

But as with the Dodge crank in a SBC, it seems like an unjustified expense. Maybe your buddy should go buy a junkyard LS for $500 instead!

Pkruse said:
But then I’ve already been told that folks who make cars go fast go more on the gut than on science.
The ones that make them go the fastest use science. :)
 
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  • #25
Sorry. I must have made a typo or something. That was just shy of 1400 hp. Not 1400 rpm. He was spinning that thing very fast, but I forget how fast.

These were race egines for airboats. They are not real boats, more like skid pans running in a couple of inches of water for a short drag race. I'm told that the hulls are 200 pounds or less, but all the rigging that supports the engine must add significantly to that number.

The real innovation was a light weight compact gear box, that enabled the use of automotive engines rather than aircraft engines, and which lowered the height of the engine significantly to keep the CG low.
 
  • #26
Pkruse said:
Sorry. I must have made a typo or something. That was just shy of 1400 hp. Not 1400 rpm. He was spinning that thing very fast, but I forget how fast.
No typo; also no previous mention of the rpm, engine size, boost or amount of nitrous being used.
Pkruse said:
A friend builds up Chevy small blocks to put out nearly 1400 hp.
mender said:
Pkruse said:
Mender:
All he knows is that he and his friends have broken Chevy cranks, but they don’t tend to break the Dodge cranks.
They shouldn't be breaking cranks at only 1400 hp; there are cranks out there that will handle 2200+ hp - if they don't rattle the engine.
Why would you think that you made a typo?
 
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  • #27
Thanks for the info. I had no idea that you could buy a shaft that strong. Any idea as to how it is designed for such strength?
 
  • #28
Reminds me of a mobile crane that I was responsible for maintaining years ago. It had a Cummins V555 engine. The crane broke. It did not have many hours on it, but it was out of warranty. Our procurement department could not find a source for a new crank, so I called up to find out price and lead time on a new engine. They informed me that they quit making the "triple nickel."

I asked, "Why."

They said, "It kept breaking crank shafts."

So we replaced it with another engine, I think that was a Cummins C-series. The other option was a Detroit Diesel 2-stroke, but we really did not want another one of those. Not for an engine that spent a great deal of time at idle speed.

That was not the only broken crank we had to replace in many different engines over the years. I've always wondered why crankshafts sometimes break when they had not been overloaded.
 
  • #29
51WDFpv9S9L._BO2,204,203,200_PIsitb-sticker-arrow-click,TopRight,35,-76_AA300_SH20_OU01_.jpg


Everything else you might need can be found here.

http://www.bookfinder.com/author/petersen-publishing-company/
 
  • #30
I've learned a great deal from you guys, now it is time for me to return the favor.

We had talked about how a reciprocating engine with a turbocharger is much like a gas turbine, if you consider the engine to be the combustor. You then have a compressor feeding a combustor feeding a turbine, just like in a gas turbine. That led to a discussion of the use of turbochargers in WWII aircraft, and speculation that the turbine exhaust may have actually provided some thrust, making it in effect the first use of a jet engine. I mentioned that I would have an opportunity to learn more and was encouraged to do that and get back to this discussion thread. I’ve learned more, and this is the result.

Airplane designers tended to favor the mechanically driven air pumps we call a supercharger today. This was especially true of the smaller aircraft like the fighters, because with existing technology at the time that could be fit into a smaller package. But some of the fighters with wider fuselages were fitted with turbochargers. The larger planes, like the bombers, were fitted almost exclusively with turbochargers. At the time, the pilot had a very complicated task when flying with a turbocharger. He had to simultaneously adjust throttle slowly, while making adjustments to the waste gate to maintain proper manifold pressure. This could seriously task load the pilot in combat, which was another reason they preferred the superchargers. They still had to make adjustments, but apparently it was easier and less critical with the technology at the time. This was not a big problem for the bombers. Of course, all planes required some sort of boost to attain the altitude they desired into the thinner air. Boost pressures were very high, but that was controlled with the waste gate. They used very little boost when at low altitude, and often none at all. I was not able to confirm what the maximum boost pressures were, only that they were very high by today’s automotive standards.

The development of superchargers started during WWI. Two companies who got an early jump on it were GE in the USA and Roll Royce in the UK, about 1917. GE was the first to develop an exhaust driven supercharger, for which they coined the name “turbo-supercharger.” That was later shorted in popular jargon to “turbocharger.” But we all need to remember that technically a turbocharger is a type of supercharger. GE developed a number of high temperature super alloys for use in the turbocharger that are still used in jet engines today. It was because of their dominance in the production of superchargers that they were the obvious choice to select to develop the first operational jet engines in the USA. Roll Royce followed a similar path in the UK. GE actually had a contract to develop a jet engine, but when WWII started the government shut that down because they did not want to pull resources away from the production of turbochargers, which were critical for the war effort. Then later in the war when England was getting blasted daily with bombs, they sent Whittle and his engine to the USA for safety, and GE was selected to help him develop his engine into something useful. After the war, the German inventor of the jet engine, Hans Von Ohain, joined the effort. This accounts for GE’s early dominance of the jet engine market after the war.

Perhaps the turbo exhaust in the WWII aircraft did at to the thrust, but the amount of this thrust was so small in comparison to the thrust of those monster propellers that we can ignore its contribution. In this, they were more like modern turboprops. With a pure turbojet, the turbine only pulls out enough energy to run the compressor, which leaves a great deal of exhaust energy to provide the thrust. The exhaust provides all of the thrust in a turbojet. But a turboprop or a turbofan engine is different. Those turbines are designed to pull the maximum amount of energy possible out of the exhaust, to drive both the compressor and the prop/fan. The prop or the fan provides nearly all the thrust, while the jet exhaust provides very little thrust. The same was even more true of the WWII aircraft. The idea was to provide as much energy as possible to those very large propellers, and they provided the thrust. The exhaust flowing aft provided essentially none of it at all.
 
  • #31
Then you have the napier nomad I.

http://www.enginehistory.org/Convention/2010/Images/KDM/Hazy/026701Nomad.jpg
 
  • #32
The easiest thing to do is pick a platform to use for your learning and go to forums used by the guys who are hopping up said platform.

It's easier to learn on something that will stay familiar throughout your studies.

Once the physics behind it is understood, you can move laterally through different makes/brands.
 

1. How do performance car parts affect torque and horsepower?

Performance car parts, such as upgraded exhaust systems, cold air intakes, and engine tuners, can increase both torque and horsepower. These parts work together to improve the efficiency of the engine, allowing it to produce more power. They can also help to reduce restrictions in the engine, allowing for more air and fuel to be burned, resulting in increased torque and horsepower.

2. Which performance car parts have the biggest impact on torque and horsepower?

The performance car parts that have the biggest impact on torque and horsepower are typically those that improve the engine's airflow and fuel delivery. This includes parts such as high-flow air filters, larger throttle bodies, and upgraded fuel injectors. These parts allow for more air and fuel to enter the engine, resulting in increased torque and horsepower.

3. Can performance car parts increase torque without affecting horsepower?

Yes, it is possible for performance car parts to increase torque without affecting horsepower. This can be achieved by installing parts that specifically target torque, such as a performance camshaft or a supercharger. These parts can improve the engine's low-end torque without significantly increasing horsepower.

4. Are there any downsides to installing performance car parts for torque and horsepower?

While performance car parts can greatly improve torque and horsepower, there are some potential downsides to consider. Upgraded parts may be more expensive and require professional installation. Additionally, some performance parts may decrease fuel efficiency and increase emissions, which could be a concern for environmentally conscious drivers.

5. Can performance car parts be used to increase torque and horsepower in any type of vehicle?

Performance car parts can be used to increase torque and horsepower in most vehicles, but the level of improvement may vary. High-performance vehicles may see more significant gains from upgraded parts, while lower-end vehicles may not experience as much of a difference. It is important to research and choose performance parts that are compatible with your specific make and model of vehicle.

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