displacement

sory i dont know but whats the advantage of having a higher displacement? say 2 engines have 200hp 200tq but one is 2.0 and one is 2.2, what does the 2.2 have over the 2.0?

200cc...maybe a flatter torque curve/more torque in the lower RPM's.... :disappoin :screwy: :eek:

And possible more potential.

no ones got a straight answer?

Perhaps you do not understand what they are saying?

Both answers were concise and to the point, and I agree with them.

10% is not much of a difference, however the easiest way to more horsepower is more displacement.

Bigger is usually better. Semi trucks use bigger motors for a reason. Even with blowers and turbos they need a BIG engine. You can only do so much with a given volume. Otherwise you would see oceanliners with a 1.6 liter with 85 sequencial turbos and a bazillion shot NOS system.

no ones got a straight answer?
In theory, the 2.2 liter engine is able to burn 10% more fuel for about 10% more power at full throttle.

To be as simple as possible, as the engine is made bigger, the power characteristics change. Often, larger engines do not always produce proportionally more power than the smaller ones. But they may produce the same amount of power at a lower engine RPM.

For example, a 1.2 liter 4 cyl motorcycle engine can make 140 hp at 9000 rpm. This is good for a lightweight sporty machine, becuase it likely makes very little power at low revs. The engine must spin fast to make the power.

My 3 liter 4 cyl engine in my boat makes the same 140 hp, but only needs to turn at 4500 rpm. This is good for pulling heavy loads, becuase the engine does not have to spin fast to make the power.

If they have the same power, I'm guessing, the 2L would have better fuel economy but you would be able to get more out of the 2.2L. If you look at cars that exist, with a civic (1.6l i think) and a camaro (350ci) with the civic you'd be lucky to get 30 hp from an exhaust system but the camaro could get from somewhere in the 100-200hp up to 400+ with carb, intake and exhaust.

In theory, the 2.2 liter engine is able to burn 10% more fuel for about 10% more power at full throttle.

To be as simple as possible, as the engine is made bigger, the power characteristics change. Often, larger engines do not always produce proportionally more power than the smaller ones. But they may produce the same amount of power at a lower engine RPM.

For example, a 1.2 liter 4 cyl motorcycle engine can make 140 hp at 9000 rpm. This is good for a lightweight sporty machine, becuase it likely makes very little power at low revs. The engine must spin fast to make the power.

My 3 liter 4 cyl engine in my boat makes the same 140 hp, but only needs to turn at 4500 rpm. This is good for pulling heavy loads, becuase the engine does not have to spin fast to make the power.
Have you heard about the gearbox?
A nice little invention that makes it possible to change the output speed to whatever speed you want!

When you are pulling loads, accelerate fast or whatever the only thing that counts it the power, if you have power you have torque I can guarantee you that. So if the engine makes 140 hp at 9000 rpm, 4500 rpm or what ever doesn't matter for the performance. The only reason for using the larger engine in the boat is cost reasons. With cars one reason to use low rev. engines is because of driveability, and of course the cost issue.

With gas turbines for example they are always using very high revs, but it's simple to gear them down to the speed that is needed.

It should also be noted that an engine with a given bore area can produce the same amount of power almost independant on displcement (stroke). So, the high revving engines usually use a large bore area but a short stroke, which means that they can produce a lot of power with a small displacement.

Have you heard about the gearbox?
A nice little invention that makes it possible to change the output speed to whatever speed you want!

When you are pulling loads, accelerate fast or whatever the only thing that counts it the power, if you have power you have torque I can guarantee you that. So if the engine makes 140 hp at 9000 rpm, 4500 rpm or what ever doesn't matter for the performance. The only reason for using the larger engine in the boat is cost reasons. With cars one reason to use low rev. engines is because of driveability, and of course the cost issue.

With gas turbines for example they are always using very high revs, but it's simple to gear them down to the speed that is needed.

It should also be noted that an engine with a given bore area can produce the same amount of power almost independant on displcement (stroke). So, the high revving engines usually use a large bore area but a short stroke, which means that they can produce a lot of power with a small displacement.
Saab, your sarcasm is completely unjustified. You seem to have missed the point of my post which was deliberatly made to be as simple as possible, since the thread starter is obvoiusly a beginner in things automotive.

So for my boat, IT HAS NO GEARBOX. One gear direct drive, like every other boat out there. Boats must have a propellor pitch and size and the final drive ratio matched to the torque curve.

To say that the only reason the larger engine is used is for cost is an astonishingly ignorant statement for you Saab, as it excludes a variety of performance and manufacutring issues.

... So if the engine makes 140 hp at 9000 rpm, 4500 rpm or what ever doesn't matter for the performance. ...

I have to disagree.
If the peak torque output was tuned for 9000 rpm, the engine is only making 81.5 ft.lbs of torque, the torque output for the same HP at 4500 rpms is 163.5 ft.lbs. Which engine would you run in a truck? which engine would you run in a lightweight Honda? Big difference here in power delivery.

With more displacement, you can tune the engine for a wider powerband, or more power overall.

With more displacement, you can have a less stressed engine, it will operate at lower rpms, it will last longer, and may actually get better mileage.

A car company can also add displacement to an existing design, as a cheaper alternative to designing a new engine when more power is needed. (classic hotrod trick)

And don't throw high tech engineering in for one engine, and not the other, as an arguement for smaller displacement.

I have to disagree.
If the peak torque output was tuned for 9000 rpm, the engine is only making 81.5 ft.lbs of torque, the torque output for the same HP at 4500 rpms is 163.5 ft.lbs. Which engine would you run in a truck? which engine would you run in a lightweight Honda? Big difference here in power delivery.

With more displacement, you can tune the engine for a wider powerband, or more power overall.

With more displacement, you can have a less stressed engine, it will operate at lower rpms, it will last longer, and may actually get better mileage.

A car company can also add displacement to an existing design, as a cheaper alternative to designing a new engine when more power is needed. (classic hotrod trick)

And don't throw high tech engineering in for one engine, and not the other, as an arguement for smaller displacement.

Good points.

Uh the gearbox multiplies torques which means you have enough power to tow and accelerate.

A truck could be powered by an S2000 motor, it would be a horrible to drive but it would work just as well as a truck powered by a 5 + liter 240 hp motor

Saab, your sarcasm is completely unjustified. You seem to have missed the point of my post which was deliberatly made to be as simple as possible, since the thread starter is obvoiusly a beginner in things automotive.

So for my boat, IT HAS NO GEARBOX. One gear direct drive, like every other boat out there. Boats must have a propellor pitch and size and the final drive ratio matched to the torque curve.

To say that the only reason the larger engine is used is for cost is an astonishingly ignorant statement for you Saab, as it excludes a variety of performance and manufacutring issues.

well actually there is a wakeboard/wakesurf boat that has a 2 speed V-drive....one to stay on plane at a low rate of speed and hold that speed for long distances (for wakesurfing) and one to bring the boat up to a higher speed (for wakeboarding) i dont remember what company made it...maybe Tige'...or Momba....i know it wasn't master craft or air nautique.... but anyway yes, you did have a good point...

I have to disagree.
If the peak torque output was tuned for 9000 rpm, the engine is only making 81.5 ft.lbs of torque, the torque output for the same HP at 4500 rpms is 163.5 ft.lbs. Which engine would you run in a truck? which engine would you run in a lightweight Honda? Big difference here in power delivery.


This is where SaabJohan’s comment about the gearbox comes in to play. By using a transmission to multiply the torque similar performance can be achieved for both engines. Assume the 4500 rpm engine uses a 1:1 gear ratio to drive the wheels. Then at a road speed corresponding to a wheel speed of 4500 rpms the drive wheels will generate 163.4 lb-ft of torque (w/ 24" tire OD). If a 2:1 gear ratio is used with the 9000 rpm engine the same road speed is generated (9000 rpm / 2), the same torque is generated (81.7 lb-ft * 2), and even the same power.


With more displacement, you can tune the engine for a wider powerband, or more power overall.


You can do that with any engine regardless of displacement.


And don't throw high tech engineering in for one engine, and not the other, as an arguement for smaller displacement.


Very good point, that is often done in arguments about displacement.

In keeping to the original post, (post #1)...

An advantage in displacement, generally means an advantage in
power. It gives you the ability to tune the powerband for a broader
and flatter torque band as opposed to a peakier one to achieve
the same maximum power.

You should not use a high or low tech engineering solution
example on only the lower displacement engine.
It is the equivalent of mis-information.

Your arguement...
You can lift a 45 kilogram weight.
Your friend, with more muscle power, can lift a 90 kilogram weight.
If you use a lever, you can now lift that 90 kilo weight too.

What you left out...
If your friend uses the same lever, he can now lift a 180 kilogram weight!!!


Cars, and trucks, also need to operate at more than one given roadspeed.

In keeping to the original post, (post #1)...

Your arguement...
You can lift a 45 kilogram weight.
Your friend, with more muscle power, can lift a 90 kilogram weight.
If you use a lever, you can now lift that 90 kilo weight too.

What you left out...
If your friend uses the same lever, he can now lift a 180 kilogram weight!!!


Cars, and trucks, also need to operate at more than one given roadspeed.


The parameter in my argument that you over looked is that both vehicles although geared differently are performing the same work at the same road speed. So both vehicles will have identical performances with respect to that particular speed. The performance range across the entire engine speed can only be obtain from the torque or power curves, neither of which was given.

Anyway, this is discussion is drifting away from IC engines but it does highlight the fact that the solution to the original question is not so straight forward. It is arguable that comparing two different engines can best be done with a measurement other than torque or power. Since torque will generally increase with displacement and power can be produced through high engine speeds. The only text book I have on IC engines suggest using mean effect pressure as the comparison since it is independent of engine size or speed.

The parameter in my argument that you over looked is that both vehicles although geared differently are performing the same work at the same road speed. .

You can state all you want that "...by adding this feature to a smaller
dosplacement engine, you can compensate for a lack of power..."
The point is, this lack of power, not that you can compensate for it.
You are misleading people here.


The performance range across the entire engine speed can only be obtain from the torque or power curves, neither of which was given.

.

Now you are getting warmer...
A broader torque curve vs. a peakier one.

By the way, 24" wheels at 4500 rpms, = ~321 mph, eh,
Nice truck!

more displacement wouldnt really give you flatter torque; that depends on the cams. but it does give you more overall torque; like for example a gain of 15lbs throughout the rev band. more torque means more power..

You can state all you want that "...by adding this feature to a smaller
dosplacement engine, you can compensate for a lack of power..."
The point is, this lack of power, not that you can compensate for it.
You are misleading people here.



I think there is some confusion about what we are disagreeing with.

Both the 4500 rpm and 9000 rpm engines are producing the same power just at different engine speeds. Therefore, the gear box is not compensating for lack of power it is utilizing high engine speeds. The gear box can only multiply torque it cannot change the power. Again, only the peak power and engine speed were given so that is what I am referring to. If someone wants to expand this argument to the entire power/torque curves then those curves should be provided.

I should have been clearer from the beginning; I never intended the 4500 rpm engine to be a larger displacement than the 9000 rpm engine. I was only comparing them based on their respective outputs at the given engine speeds.

For the record I agree that if you have two engines with a significant difference in displacement it will be easier to generate a flatter torque for a given peak power with the larger displacement engine.

A larger engine will not offer a broader torque curve, it will just offer a higher torque curve.

And when it comes to 4500 rpm vs. 9000 rpm engine a gearbox will solve the problem with the lack of torque. Even if the engine is fitted in a boat you can simply use a simple gear to increase torque and reduce speed if that suits your propeller. The same method have been used in for example airplanes, take a look at any turbo-prop aircraft, the turbine is never directly connected to the propeller since it spins with a really high speed, so do they fit a larger turbine? No they simply gear it differently.

When it comes to fuel efficiency larger engines loose, this is due to that they must go with a lower load at part throttle so even if they can offer a low specific fuel consumption they can't make use of that during daily driving.

Then there is the fact that a larger engine can't produce specific outputs as high as smaller engines due to stroke length (rpm capability) and flame path of the combustion chamber.

Ok i'm goin to make this simple as possible! If you're talkin about honda well heres what you need to know...

ALL MOTOR ppl wants bigger displacement to squeeze every ounce of potential out of there motors. It is NOT NEEDED when you're goin FI. All motor ppl want TORQUE and it'll put instant power to the ground while turbo you have to wait for boost! THe boost will creat high torque and high HP of course. Look at the '00-'03 s2000 which has 240 hp and 158 lbs of tq i believe vs the '04 s2k 240 hp with 164lbs of torque. Same hp but different torque numbers. The old s2k has 2.0 ltr while the new ones have the 2.2ltr. Rod/stroke ratio is differnt. The longer the ratio the more torque it creates so there for cars with higher torque revs less. THey used to rev up to 9 grand now its 8 grand. Doesn't mean its weak. They tuned it to wear the highest peak power at lower rpm. This is the best way i can explain it. Correct me if i'm wrong if you will...

I think you guys are forgetting that its possible to use FI on high displacement engines.
In short, the higher displacement, the more potential. Period.

I don't think more potential is related to more displacment. Engine work is determined not only by torque, but rpm.

yea but the bigger the engine; the bigger turbo you need! have u guys seen the turbos they use in drag mustangs? they are HUGE!

yea but the bigger the engine; the bigger turbo you need! have u guys seen the turbos they use in drag mustangs? they are HUGE!


Thats not true about hondas.

I don't think more potential is related to more displacment. Engine work is determined not only by torque, but rpm.

It does when it involves all motor.

I think there is some confusion about what we are disagreeing with.

Both the 4500 rpm and 9000 rpm engines are producing the same power just at different engine speeds. Therefore, the gear box is not compensating for lack of power it is utilizing high engine speeds. The gear box can only multiply torque it cannot change the power. Again, only the peak power and engine speed were given so that is what I am referring to. If someone wants to expand this argument to the entire power/torque curves then those curves should be provided.

....

Actually, I think we are not listening to each other, to a certain degree.
You are also correct, the power produced at the rear wheels is the same in your example.

I have been referring to the power curves, though. And a chart would be most helpful. I will have to see if I can find a good example.

In the mean time, anyone agree or disagree with the following:

A truck motor, needs to make low end power to haul a load. The smaller motor is a liability here. Over gearing will increase heat and lower life expectancy.

A commuter car needs light weight, low cost, and efficiency. A compromise in design is advantageous here.

A Honda S2000 likes light weight, and good accelleration. A smaller, higher technical engine is advantageous here.

You do not have to increase the stroke of an engine to increase it's displacement.

Aircraft turbine engines seem out of place in an automotive forum. And if anything, they exemplify a potential problem with gearing, ie: extremely limited operating range. For cars, they need to operate from 0 to say 90 mph. If the engine only makes power over a 700 rpm band, many, many gears need to shift.

Thats not true about hondas.


actually it is...let say for example you have a t25 turbo; you put it on a d15; doesnt it lag till higher rpm? now take that same turbo, and put it in a k24, itll boost pretty quick but may start surging as the k24 revs towards the redline. thats why when you match a turbo, it requires that you know the displacement of the engine.

actually it is...let say for example you have a t25 turbo; you put it on a d15; doesnt it lag till higher rpm? now take that same turbo, and put it in a k24, itll boost pretty quick but may start surging as the k24 revs towards the redline. thats why when you match a turbo, it requires that you know the displacement of the engine.

I know what you're sayin. But you forgot about the compression ratio. Higher the ratio...the less it'll lag. Bigger motors still lags. SUPRAS HAVE NASTY TURBO LAG and they have the inline 6 motor! It doesn't matter about the displacement when it comes to turbo. Trust me my boy is running low 11s on his turbo hatch gsr motor. Still a 1.8ltr. Now you think an all motor honda will see those times on stock displacement? Its possible but its really hard. Even if you stroke the motor out but you still have a better chance than the stock displacement.It doesn't take as much to be fast when it comes to force induction. Like i said before...you need to squeeze every ounce of potential when it comes to all motor. So i'm not too familiar with the K24 motors compression ratio but heres a food for thought...

Higher compression pistons do create a stronger vacuum, and create a more complete burn (resulting in an increase in exhaust gases).It will help you spool faster.

I mean really you can't compare k24 to d15b. You can take k24 to a stroked out k24 into .2 ltr then compare the two. Does it mean that that stroked out motor would it be faster? No. But if its all motor...do you think the stroked out motor would be faster? Most of the time..Yes! Why? cause it increases torque and instant power to the ground unlike turbo. Since its stroked out, of course the torque will increase and torque it's very important for all motor.Thats why i said you dont really need to get a bigger displacement when it comes to turbo. Doesn't matter what the size is, you'll still feel the turbo lag. I hope i explained it well enough.

im comparing the displacement; if youve ever calculated the mass flow rate of an (large displacement)engine; you'll see that it requires more mass flow then a smaller engine. then, plot it on a compressor map; the smaller displacement engine requires less air. a turbo is efficient around a certain amout of flow with a certain amount of boost. the reason why the supra has huge turbo lag is because of the amount of boost. put that same turbo on a honda engine(with same cr), it will lag even more. put that same turbo on a mustang engine(with same cr), it will lag less. of course its not all about the compressor; the exhaust side of the turbo also will determine amount of lag, etc. if you want me too, i can plot a map for a b18 and a b16 engine and post it up.

Ok i know all that bro. What i'm tryin to say is ...it is not really necessary to do all that. You see what i'm say'n? You can keep a stock displacement when goin FI and be fast already. A turbocharged built b16 can hit 11s and its still a 1.6 ltr. A b16 all motor is very hard to get it into the 12s. For an example...i had a full b16a swap and i love stay'n all motor. I bought a complete ITR shortblock with CTR pistons from a good friend of mine. All i did is switched the block and i hit high 13s. Of course i had bolt ons and minor suspension work, upgraded clutch (action clutch). I mean yeh you can hit 13s b16a but it requires more work than a 1.8 ltr. So again its not really necessary to stroke the motor when goin force induction :)

ok i see what you are talking about. i was never talking about stroking or increase the displacement, i was just comparing large displacement(like the +3l v6/8s) and small displacement engines; boostwise. i agree that you can just keep the motor stock displacment for FI. come to think of it, i dont think any of the 8second turbo hondas are bored or stroke(mostly stock displacement b18's), or am i wrong?.

i dont think any of the 8second turbo hondas are bored or stroke(mostly stock displacement b18's), or am i wrong?.

Actually some bored it out to 1.9 or bigger. They're just competiting to be the fastest.

Why is this forum limited to that Honda bs? I have nothing against it, but that's all anyone talks to here. There ARE other make engines with higher displacements than Hondas, you know. And a lot of them can get a lot better than 11s, easier.

You go complain to the mods about it then. Everyone talks about everything here. They took out Honda technical forum and merged it with all the others. So you gonna see lots of honda heads here.

I'm not complaining about the Honda influence, I'm talking about the closed-mindedness. 2 liters isn't exactly the biggest engine in the world.

2 liters isn't exactly the biggest engine in the world.


It is in the civic/integra world. Remember that honda civics are light as hell.

Yeah but I don't see why Engineering/Technical has to be exclusively a civic/integra world. So they're light. They still can't get any faster than 9s or 8s. Most of them can't break 13s without at least 6 or 7k.

Oops..I meant 14s.

I broke into high 13s and it cost me well under 3300. The motor is still stock. Stock b16a (1200 for the motor) on a CRX would hith 14.7 at best, b18c5(3500-4200) would hit high 13s at best. I had a full b16a swap for 1500. I bought integra type r shortblock from a friend of mine for 1200. My compression i believe was 11:7 or 11:8 on civic type r pistons. Slapped on my b16 head, jdm dc sport headers (used), action clutch, falken azenas tires, cat-back and cold air intake along with a chipped ecu but hardly any difference. . . Thats all motor. If it was turbocharged B18b or ls motor ...high 12s for sure. LS motors can go anywhere between 700-1200 and a bolt on turbo kit can go anywhere between 2700-3200. Do the math ;)

Yeah, I have to agree. $5000 and any old V8 willput you way under 10 seconds. But I do enjoy seeing these guys get wild with these little 4 cylinders.

I'm just tryin to correct the guy about the price. It doesn't take 6-7g's to make a honda run 14s.

Alright, I'll correct myself. 4 grand for mid 13s. It still doesn't prove any point. And that's still a large amount of money for that particular timeslip.
My point was that higher displacements have more potential than the lower. And I'm not talking exclusively about same block with a little more stroke. The small displacement motors only advantage today is the OHC setups. This wouldn't mean that higher displacements can't have more potential, because you can also go out and buy an overhead cam V6 or V8 from some, though few places, and get the same amplification, it its just not needed for higher displacements because they naturally can produce more. In most cases small displacements are for economy. That's all.
And no, I'm not messin with Hondas or whatever, but its ignorant to say a smaller explosion can have more power than a large one. It should be common sense.

new Nissan Maxima's will run 14's with a CAI, exaust, headers, and Mass air flow sensor...all that cost less than 1000...and dont tell me otherwise...ive seen with my own two eyes...

Alright, I'll correct myself. 4 grand for mid 13s. It still doesn't prove any point. And that's still a large amount of money for that particular timeslip.
My point was that higher displacements have more potential than the lower. And I'm not talking exclusively about same block with a little more stroke. The small displacement motors only advantage today is the OHC setups. This wouldn't mean that higher displacements can't have more potential, because you can also go out and buy an overhead cam V6 or V8 from some, though few places, and get the same amplification, it its just not needed for higher displacements because they naturally can produce more. In most cases small displacements are for economy. That's all.
And no, I'm not messin with Hondas or whatever, but its ignorant to say a smaller explosion can have more power than a large one. It should be common sense.


Go do some research. you'll find useful infos here ..

www.honda-tech.com

new Nissan Maxima's will run 14's with a CAI, exaust, headers, and Mass air flow sensor...all that cost less than 1000...and dont tell me otherwise...ive seen with my own two eyes...


Umm the already run mid 14s stock. Oh and its not a 4cyl.

Go do some research. you'll find useful infos here ..

www.honda-tech.com


lol what are you smoking? Info on what?

lol what are you smoking? Info on what?

Dude i dont know whats your problem with hondas. I showed you that site so you can get an idea how fast they go without "6-7g's." Thats just so stupid to say something like that that you dont know anything about.

I told you I don't have a problem with them. I don't need to be educated on them though. I corrected myself, and yes, I looked at the site. Nothing on there changed anything. And stop getting so offended about that. It was just a comment. My point is something completely different as I'm trying to keep relevance to the thread subject.

I wasn't getting offended. Your just makin stupid claims about something thats not true. Whatever just leave it at that.

I didn't know tantrums were allowed here.
You do that.

Ok...whatever u say.

Umm the already run mid 14s stock. Oh and its not a 4cyl.

no no no... runs low 15's...well at least wtih my friend driving...he isnt the greatest shifter...