100 horsepower per liter naturally aspirated
11-09-2007, 10:43 AM
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I think there is one valuable, large market where HP/L does matter, and that is in motorcycles, specifically sportbikes. This is what the buyers want. They want a 160-180hp powerplant, packaged in a bike small enough that ones legs can comfortably fit across the width, and they want it to weigh as little as possible. So by everyone's logic here, a pushrod motor would be superb. It weighs less, costs less, is physically smaller, and once you double the displacement, you can make the same power outputs.
Now let's look at this fact, the only sportbikes that sell are DOHC, high specific output, very high revving, torqueless wonders. What are the Japanese thinking? Well let's find an automobile, low specific output engine that fits the bill. How about the GM 2.4l DOHC I4 used in late model Cavy Z24s? It makes like 160hp, and with just a 6200rpm redline, has healthy low end torque models. First of all, it's a terrible choice because it's an iron block, but it could be alloy so let's ignore that. The engine won't fit in a Honda Goldwing, let alone a CBR. And if you did get it to fit, you couldn't fit your legs around it, the weight would be significantly more, and you'd still get raped by the engine with 1/4 the displacement. The fact is, with an inline configuration, DOHC engines are just as compact as pushrod engines. But because of the flow levels attainable by the DOHC engines, they make MUCH more power, and have much higher specific outputs. Perfect for sportbikes.
The only downside to a high specific output engine is that they are high RPM engines. RPM kills engines. But since sportbikes rarely get ridden, and certainly don't rack up miles like cars, there's no problems with the bike's engines only lasting to 40,000 miles. So the next problem with high rpm, the lack of low end, off idle torque. The S2000 sucks to drive for that reason. How many of you ride sportbikes? Is there ever a complaint of not enough low end? I had the chance to ride a CBR1000RR a year or two ago. I pulled it out of my driveway, and let the clutch out. 30mph. I didn't even have to touch the throttle, besides what I needed to do so it wouldn't stall. There wasn't much power, but the accelerative force was tremendous, at ANY engine speed. Fact is, the bike is so light because of the high technology employed, that it doesn't take much to get it moving WELL ahead of traffic.
Lastly, let's compare it to the low specific output, pushrod sportbikes. Errr, sportbike. The Buell. Is Buell still a company? They sell fewer bikes than GM does doughnuts. The largest displacement sportbike Buell makes is 1200cc. And with a power output just shy of 100hp, it is not exactly exciting. In fact, there isn't a 600cc sportbike that couldn't walk away from it. So linearly speaking, in order to get the Buell to compete even with other 1000cc bikes, it needs over 160hp, meaning it needs 1950cc, aka 2.0l. Find me a 2.0l powerplant that will fit inside a sportbike, and we're good to go right? Well, not really. It weighs 20lbs MORE than the leading 1000cc sportbike. In fact, of the big 4, everyone weighs significantly less than the Buell. So now it needs even MORE power, aka even more displacement, just to keep up. And that's not event taking into account the significant weight that'd be added by having a 2.1l powerplant.
I like looking at HP/L, because it shows true performance tuning. It shows levels of volumetric efficiency reached that was never thought possible. It shows the technological, and engineering, advances that we have made. However, I can realize that in a car, it is for the most part dismissable.
Now let's look at this fact, the only sportbikes that sell are DOHC, high specific output, very high revving, torqueless wonders. What are the Japanese thinking? Well let's find an automobile, low specific output engine that fits the bill. How about the GM 2.4l DOHC I4 used in late model Cavy Z24s? It makes like 160hp, and with just a 6200rpm redline, has healthy low end torque models. First of all, it's a terrible choice because it's an iron block, but it could be alloy so let's ignore that. The engine won't fit in a Honda Goldwing, let alone a CBR. And if you did get it to fit, you couldn't fit your legs around it, the weight would be significantly more, and you'd still get raped by the engine with 1/4 the displacement. The fact is, with an inline configuration, DOHC engines are just as compact as pushrod engines. But because of the flow levels attainable by the DOHC engines, they make MUCH more power, and have much higher specific outputs. Perfect for sportbikes.
The only downside to a high specific output engine is that they are high RPM engines. RPM kills engines. But since sportbikes rarely get ridden, and certainly don't rack up miles like cars, there's no problems with the bike's engines only lasting to 40,000 miles. So the next problem with high rpm, the lack of low end, off idle torque. The S2000 sucks to drive for that reason. How many of you ride sportbikes? Is there ever a complaint of not enough low end? I had the chance to ride a CBR1000RR a year or two ago. I pulled it out of my driveway, and let the clutch out. 30mph. I didn't even have to touch the throttle, besides what I needed to do so it wouldn't stall. There wasn't much power, but the accelerative force was tremendous, at ANY engine speed. Fact is, the bike is so light because of the high technology employed, that it doesn't take much to get it moving WELL ahead of traffic.
Lastly, let's compare it to the low specific output, pushrod sportbikes. Errr, sportbike. The Buell. Is Buell still a company? They sell fewer bikes than GM does doughnuts. The largest displacement sportbike Buell makes is 1200cc. And with a power output just shy of 100hp, it is not exactly exciting. In fact, there isn't a 600cc sportbike that couldn't walk away from it. So linearly speaking, in order to get the Buell to compete even with other 1000cc bikes, it needs over 160hp, meaning it needs 1950cc, aka 2.0l. Find me a 2.0l powerplant that will fit inside a sportbike, and we're good to go right? Well, not really. It weighs 20lbs MORE than the leading 1000cc sportbike. In fact, of the big 4, everyone weighs significantly less than the Buell. So now it needs even MORE power, aka even more displacement, just to keep up. And that's not event taking into account the significant weight that'd be added by having a 2.1l powerplant.
I like looking at HP/L, because it shows true performance tuning. It shows levels of volumetric efficiency reached that was never thought possible. It shows the technological, and engineering, advances that we have made. However, I can realize that in a car, it is for the most part dismissable.
Let me reiterate.
HP/Liter doesn't matter, except in Size Limited Classes and Taxes, etc.
Like was already stated, having Higher HP/Liter means what? Absoultely nothing except that you rev higher.
Speaking in terms of performance, who will win. A Bike with 205 HP/Liter or a bike with 185 HP/Liter? Oh, You can't tell, because you don't have enough information. In other words, HP/Liter doesn't mean ****.
On the Street, is Displacement limited like it is in MotoGP? No. So when you come up to a Liter Bike in your 600 CC sport bike, is your 205 HP/Liter going to beat is 185 HP/Liter? Nope, He still makes 185 HP and you don't. You know why? He has More Displacement. The 600cc's HP/Liter is higher, which is another way of saying It'll Rev higher than the Liter Bike, but it will still loose...
There are Cars, (V8's et al) that have high HP/Liter like a Motorcycle. They're Ferrari's, and lambos. They rev high as ****, and are about as reliable as a motorcycle too. And the price is also insane. So a F430 with higher HP/Liter vs a C6 Z06 is still not going to win. Because HP/Liter doesn't mean ****.
The ONLY time HP/Liter is important is if you're in a Displacement limited environment. Since the street doesn't have class restrictions. A Liter bike will most likely dominate a 600CC bike, and a C6Z will clobber a F430. Life's tough...
-Dan
11-09-2007, 10:49 AM
#802
FormerVendor
Yes, that's really all it comes down to ever. Even in displacement limited classes its still just HP winning as thats really why one is faster than another but at the same engine size it also means the are nigher hp/l as well. But they are faster solely due to having more power.
I don't think you fully understood what was said above.
Let me reiterate.
HP/Liter doesn't matter, except in Size Limited Classes and Taxes, etc.
Like was already stated, having Higher HP/Liter means what? Absoultely nothing except that you rev higher.
Speaking in terms of performance, who will win. A Bike with 205 HP/Liter or a bike with 185 HP/Liter? Oh, You can't tell, because you don't have enough information. In other words, HP/Liter doesn't mean ****.
On the Street, is Displacement limited like it is in MotoGP? No. So when you come up to a Liter Bike in your 600 CC sport bike, is your 205 HP/Liter going to beat is 185 HP/Liter? Nope, He still makes 185 HP and you don't. You know why? He has More Displacement. The 600cc's HP/Liter is higher, which is another way of saying It'll Rev higher than the Liter Bike, but it will still loose...
There are Cars, (V8's et al) that have high HP/Liter like a Motorcycle. They're Ferrari's, and lambos. They rev high as ****, and are about as reliable as a motorcycle too. And the price is also insane. So a F430 with higher HP/Liter vs a C6 Z06 is still not going to win. Because HP/Liter doesn't mean ****.
The ONLY time HP/Liter is important is if you're in a Displacement limited environment. Since the street doesn't have class restrictions. A Liter bike will most likely dominate a 600CC bike, and a C6Z will clobber a F430. Life's tough...
-Dan
Let me reiterate.
HP/Liter doesn't matter, except in Size Limited Classes and Taxes, etc.
Like was already stated, having Higher HP/Liter means what? Absoultely nothing except that you rev higher.
Speaking in terms of performance, who will win. A Bike with 205 HP/Liter or a bike with 185 HP/Liter? Oh, You can't tell, because you don't have enough information. In other words, HP/Liter doesn't mean ****.
On the Street, is Displacement limited like it is in MotoGP? No. So when you come up to a Liter Bike in your 600 CC sport bike, is your 205 HP/Liter going to beat is 185 HP/Liter? Nope, He still makes 185 HP and you don't. You know why? He has More Displacement. The 600cc's HP/Liter is higher, which is another way of saying It'll Rev higher than the Liter Bike, but it will still loose...
There are Cars, (V8's et al) that have high HP/Liter like a Motorcycle. They're Ferrari's, and lambos. They rev high as ****, and are about as reliable as a motorcycle too. And the price is also insane. So a F430 with higher HP/Liter vs a C6 Z06 is still not going to win. Because HP/Liter doesn't mean ****.
The ONLY time HP/Liter is important is if you're in a Displacement limited environment. Since the street doesn't have class restrictions. A Liter bike will most likely dominate a 600CC bike, and a C6Z will clobber a F430. Life's tough...
-Dan
11-09-2007, 10:54 AM
#803
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Yes, that's really all it comes down to ever. Even in displacement limited classes its still just HP winning as thats really why one is faster than another but at the same engine size it also means the are nigher hp/l as well. But they are faster solely due to having more power.
If you could have a Liter bike in a 600CC class - that would mean lowering your HP/Liter... But wouldn't it be worth it still? If it's still worth it, then what does that say about HP/Liter? It's meaningless.
-Dan
11-09-2007, 06:46 PM
#804
Exactly - in a Displacement limited field, HP/Liter is just a byproduct of having more HP! LOL The guy with more Absolute HP still wins (driving skill aside...)
If you could have a Liter bike in a 600CC class - that would mean lowering your HP/Liter... But wouldn't it be worth it still? If it's still worth it, then what does that say about HP/Liter? It's meaningless.
-Dan
If you could have a Liter bike in a 600CC class - that would mean lowering your HP/Liter... But wouldn't it be worth it still? If it's still worth it, then what does that say about HP/Liter? It's meaningless.
-Dan
That's it in a nutshell, Dan.
11-10-2007, 10:29 AM
#805
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11-11-2007, 03:08 PM
#806
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Responses that cost every forumer undue bandwidth usage,and them posting em,could even moreso utilise her services.
ye could put a nice pic of a car or some chicky babe atleast!
i'm not into his gay thing ye dig!
11-11-2007, 09:37 PM
#807
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Everything in this thread has been repeated about 10X, it has gone off topic about 200x, and very little new information gas been shared. I stopped replying to this thread about 4 months ago because you could see where it was going.
The fact is that Hp/L is just a category to rate engines in, a statistic that doesnt say anything about how the engine performs without additional information- 125cc dirt bikes makes great Hp/L but would suck in a full weight street car. I know it is a drastic comparison, but in other words the displacement is every bit if not more important than Hp/L. Then there is the power curve, total output, weight, size, cost, durability, etc. - all of which are probably ahead of Hp/L on an engineers check list of what they want when developing a new engine.
The fact is that Hp/L is just a category to rate engines in, a statistic that doesnt say anything about how the engine performs without additional information- 125cc dirt bikes makes great Hp/L but would suck in a full weight street car. I know it is a drastic comparison, but in other words the displacement is every bit if not more important than Hp/L. Then there is the power curve, total output, weight, size, cost, durability, etc. - all of which are probably ahead of Hp/L on an engineers check list of what they want when developing a new engine.
04-25-2008, 03:42 PM
#808
wow. so i didnt read all... 41 pages of this, however i do have to say something that may or may not have been said. are you talking about rwhp or bhp. im pretty sure s2k dont put down 240 to the wheels so i would think its is reasonable to have a streetable 570bhp car. thats like what 480 with a 15% drivetrain loss. could do a poll on gas mileage above 450rwhp and their set up and see what route to take.
11-30-2008, 01:37 PM
#811
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Please every one just stop!!! leave sport bikes/F1 / train engine / jet engine out of this. there good at what they were built to do There a bunch of great reasons why there no jet/train /sportbike engine power cars being built.
I used to race sport bikes. you cant compare them to cars. A 600CC (110hp)is not that much faster then a 1000cc(160hp) sport bike Hell a 6 million dollar honda V5 1000cc(298hp) race bike is not that much faster then a 160hp bike. Why all these sport bike are passing the level which a human can ride and get the power to the ground.
A person can flip a honda V5 racing bike by just twisting the grip to much at 160 mph. would this bike be more fun to ride around then my street bike(160hp) no. no use but on a race track.
HP/l means nothing. There no prefect engine that can do everything.
IF drag race build a drag engine. If F1 racing build a 20k rpm motor. For street build what ever makes you happy. I have a 800hp car that loses alot on the street cause the tires just spin. im not willing to change anything to mess with the handling of the car. but it get 26 mpg and i smile when i drive it
I used to race sport bikes. you cant compare them to cars. A 600CC (110hp)is not that much faster then a 1000cc(160hp) sport bike Hell a 6 million dollar honda V5 1000cc(298hp) race bike is not that much faster then a 160hp bike. Why all these sport bike are passing the level which a human can ride and get the power to the ground.
A person can flip a honda V5 racing bike by just twisting the grip to much at 160 mph. would this bike be more fun to ride around then my street bike(160hp) no. no use but on a race track.
HP/l means nothing. There no prefect engine that can do everything.
IF drag race build a drag engine. If F1 racing build a 20k rpm motor. For street build what ever makes you happy. I have a 800hp car that loses alot on the street cause the tires just spin. im not willing to change anything to mess with the handling of the car. but it get 26 mpg and i smile when i drive it
Last edited by BigRich954RR; 11-30-2008 at 01:50 PM.
07-18-2012, 01:39 PM
#812
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100 hp per liter anyone want to talk about torque? all horsepower numbers are great but you can forget about hp if it won't rip out of the hole from a stop. I wonder if anyone has a 600+ hp naturally aspirated ls1 with stock bore and stock stroke who is winding it over 7500 rpms on gas not e-85 or race fuel.
07-27-2012, 03:03 PM
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I still don't see how hp/L is meaningless. It is a great way to compare engines of a given displacement, in terms of their volumetric efficiency, high rpm stability, material selection and so on. F20Cs, 1L bikes and F1 cars are engineering marvels are they not? LSx engines are no less marvelous in my opinion, but they just weren't designed as a package to be happy in the 5252 rpm + range. Piston velocity is approaching F1 territory spinning one of these engines to 8000 rpm. That requires a lot of design considerations, not to mention the valve train, side loading, head flow, high wear and stress. It would be expensive to address all of these.
08-07-2012, 06:53 AM
#815
Else where in this forum is Camster with shift points at 6,800 rpms {so the cam is not that big} and is making 643 rear wheel hp [740 fwhp] 440 CI ls7 using an lsx block.
If my math is rite, hi is making 102.77 hp per liter in full accessory street car, not even roll bars.
The same car weights under 3,400 lbs with halve tank and no driver, which make's that under 5 lbs per hp power to weight ratio, if power to weight ratio is what counts.
I believe his car hits the Mark of the OP on this old but revived thread.
If my math is rite, hi is making 102.77 hp per liter in full accessory street car, not even roll bars.
The same car weights under 3,400 lbs with halve tank and no driver, which make's that under 5 lbs per hp power to weight ratio, if power to weight ratio is what counts.
I believe his car hits the Mark of the OP on this old but revived thread.
08-07-2012, 12:23 PM
#816
Yes Camster's car is a sick freak lol I'm down on cubes compared to him, but only turning alt and water pump on mine, and I have a slightly bigger cam.....took a while to build up my forearms for the manual steering lol.
It is not just one or two good parts, but all the parts speced and used correctly as a package to get there
It is not just one or two good parts, but all the parts speced and used correctly as a package to get there
08-27-2012, 03:02 PM
#817
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The Point When it comes down to the root of what makes a car fast given everything else is equal, it's torque-area-under-the-curve-to-weight ratio that makes it dance. Sure peak figures are great, but it's torque that can slingshot you out of a corner (or the hole, depending on your preference) and keep you in power for another 4k rpm that really makes a great racecar. Neither the guy nor the car you just beat are going to care that it took you X more/less liters to do it.
I have a preference for N/A midrange displacement pushrod power. Currently building up a 360 cube, 9k rpm redline, road racing engine.
Comeon, the springs only have to last a few races, right? haha
I have a preference for N/A midrange displacement pushrod power. Currently building up a 360 cube, 9k rpm redline, road racing engine.
Comeon, the springs only have to last a few races, right? haha
09-29-2012, 04:17 PM
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I still don't see how hp/L is meaningless. It is a great way to compare engines of a given displacement, in terms of their volumetric efficiency, high rpm stability, material selection and so on. F20Cs, 1L bikes and F1 cars are engineering marvels are they not? LSx engines are no less marvelous in my opinion, but they just weren't designed as a package to be happy in the 5252 rpm + range. Piston velocity is approaching F1 territory spinning one of these engines to 8000 rpm. That requires a lot of design considerations, not to mention the valve train, side loading, head flow, high wear and stress. It would be expensive to address all of these.
Really, in most street cars, there's no reason to try to make a lot of power out of a small engine. That's a lot of stress on the engine. That era of F1 racing was before they instituted new rules regarding how often the teams could replace engines. On the street, it's better to have a big displacement engine that isn't stressing itself out to push the car to highway speeds than a small engine that requires downshifting and high revs to do the same.
09-29-2012, 04:59 PM
#820
FormerVendor
HP/L is pretty meaningless. It makes more sense to talk about HP/lb. A 7.0L LS7 will make over 500 hp. A Nissan V6 at 3.5L makes more HP/L, but weighs more and takes up more space than the 7.0L pushrod engine. At the same point, they get comparable gas mileage. However, the V8 is much more powerful. Just because the LS7 uses a few more cubes to make that power, doesn't mean it's any less of a technological marvel.
Really, in most street cars, there's no reason to try to make a lot of power out of a small engine. That's a lot of stress on the engine. That era of F1 racing was before they instituted new rules regarding how often the teams could replace engines. On the street, it's better to have a big displacement engine that isn't stressing itself out to push the car to highway speeds than a small engine that requires downshifting and high revs to do the same.
Really, in most street cars, there's no reason to try to make a lot of power out of a small engine. That's a lot of stress on the engine. That era of F1 racing was before they instituted new rules regarding how often the teams could replace engines. On the street, it's better to have a big displacement engine that isn't stressing itself out to push the car to highway speeds than a small engine that requires downshifting and high revs to do the same.