black_knight

iTrader: (1)

The newest LSx family engines do. The L92 has VVT. The reason why not before is because it wasn't needed: they spent their research $$$ on improving head flow and intake design and it did the trick pretty well I'd say.

black_knight

iTrader: (1)

Here is the key: HP/L works only when size/weight is directly correlated with displacement! But even a stopped clock tells the right time twice a day. Since this correlation is not always (and even not mostly) the case, it makes 1000 times more sense to say HP per size/weight than it does HP/L.

Since that is what you actually mean, then why have the BS middleman?

LSGunZ28

iTrader: (8)

I did read what you wrote. But Id take a harely over a sport bike, for the very reason that I want torque in all RPMs.

also you are comparing sportbokes with LSX engines. Its different, LSX engines go in sport cars, not bikes.

I dont doubt your knowledge, but Im just sayin'

LSGunZ28

iTrader: (8)

so do they have a single cam that changes lobes/lobe location on the shaft? or actual 2 cams that switch lifters?

black_knight

iTrader: (1)

It's a single cam that has a cam phaser. See here:

FieroZ34

iTrader: (1)

Believe it or not, a 1 liter engine is a bit smaller than an LS1. A little. Weight is so critical, and close-matched, in the sportbike world that the 600s and 750s run almost as quick as the 1000s, which sport 40 more hp, because the 1000s weigh in at more. Where do think this weight is? The brakes? No, it's the engine. Believe it or not, an extra 400cc adds enough weight in a bike to be extremely noticeable, and barely gets offset by the 40hp it adds.

That's my point exactly. It isn't because they are bike engines at all, it's because they are an inline configuration. And the V style engines still used in bikes, while few and far between, are much larger than the inlines, and weigh quite a bit more. However they are still small enough to fit in the bike obviously.

So why do motorcycle companies sell pretty much identical bikes, but with different engine sizes? Because liters DO matter. The motorcycles are at such a staggering high level of performance tuning that one manufacturer will not significantly overpower another's without more displacement. Look at Kawasaki, their bike needed an extra 37cc to keep up!

An inline DOHC engine alleviates the problems associated with size. Why won't an LT5 engine fit in my Fiero's engine bay, while an LS1 will? Both are 5.7l, both share very similar block design. It's because of the LT5's DOHC heads. They add so much WIDTH to the engine, that it simply won't fit. The height or length isn't an issue, and even if it was, I can still lower the engine's mounting on the cradle or move the engine side to side. This is the same reason why the LT5 won't fit in a 4th gen Camaro. The engine bay is so tight, with respect to width, that the huge DOHC top end won't fit. However the topend on a DOHC engine doesn't add width in an inline configuration, it just adds height, about 2" on most engines, which can be easily found in most engine bays.

You're right, the M3 engine does weigh more than the LS1. That's because it's made out of iron! No **** a cast iron block is going to weigh more than an alloy. You're simply genius. A DOHC inline 8 wouldn't be huge in height or width, it'd be very compact actually. But the length would go beyond a limit that most engine bays could handle. So they take the 8 slugs, put them in a V configuration, and double the width. But most engine bays can still handle this width, barely, with the pushrod engine. However in terms of width and height, the inline is much more compact.

Exactly. Their engines are tuned to such a high level, as are their competitors, that the HP/L extracted is very important.

An LS7 weighs more than the LS2, which weighs more than the LS1. It isn't much, but they do. Now if these engines were in a package that weighed 400lbs total, the 20lb differences between them would be HUGE. And if they were tuned to the level that sportbikes are, then the power would barely offset the added weight. And thus we get the reason why the GSX-R1000 is actually quicker than the GSX-R1300 Hayabusa.

FieroZ34

iTrader: (1)

You've obviously never ridden a sportbike. If you had read what I'd written, you'd see the part where the bike has low end. Almost too much for it's own good, as the CBR I rode could lift the tire, without any clutch input, in 1st or 2nd gear at any RPM. Not to mention there isn't a single point in the rpm range where the sportbike won't annihilate a Harley. From a 1500rpm roll, a GSX-R1000 would destroy any Harley made. It'd be like a Z06 lining up to a 13 liter 18-wheeler. Yah, the Z06 is down on displacement, power, and torque, but it still won't be a contest.

I'm not comparing sportbike engines to the LSX series, I'm simply pointing out a class where HP/L is very important. Because the manufacturer's keep such a high level of tune, and strive to keep displacements the same, that the power extracted from each unit displacement is crucial to that machine's ability to outperform the others.

Quick Double Nickel

iTrader: (5)

I guess I should have referred to the thread as "Horsepower per cubic inch displacement", and then maybe you'd understand what the question really was. Using the HP/L measurement is just a universal way of looking at an engine's specific output since most global car manufacturers use liters to describe displacement, not cubic inches. Engine size, displacement, liters, cubic inches - it's all the same thing. It's not ricer math.

While there is no doubt that fuel consumption, packaging, and weight all play pivotal roles in the use of one engine over another, there are some universal concepts that make one engine better than another. Just like the LSx engines are a vast improvement over the old flathead V8s, so too will the LS1 become "old" technology.

I think the combination of miami993c297 is the future of LSx engine development, at least in the aftermarket realm, but I would like to see this in production motors with MAF operating systems and great street manners. So, with that in mind, what innovations are needed for the future to get to the level of performance displayed by miami993c297 in a production vehicle?

germeezy1

I think so many people get caught up in specific output they fail to see the real story. The LSx motors are so good at what they do because of there power density. Not many engines can contain 427 ci inside of an engine that weighs less and is smaller than a 281 ci DOHC Ford engine. Its the reason why a well maintained LSx motor can go to 150k or 200k miles because its relatively understressed for its power. There isn't a 505 hp car on the whole planet other than the C6 Z06 that comes with a 100k mile powertrain warranty. Now that says something about engineering an engine to have many contradicting goals.

1. Big Power Big Fuel economy
2. Big displacement small size
3. Cammy high rev power great low end torque
4. Long stroke High Rpm

This only gets better when they incorporate tricks like DI and VVT into the LS series.

TT632

iTrader: (3)

My argument against comparing any engine by HP/liter (or HP/CI) is that you are looking at a peak number at an instant in time that varies engine to engine. It has very little to do with a vehicles ability to accelerate unless you are sitting on that peak all of the time.

If you built an engine to optimize it's peak HP # you would most likely kill its ability to accelerate and hurt drivabilty.

germeezy1

Does the words power under the curve ring a bell?

LSGunZ28

iTrader: (8)

I have not ridden one, no.

You still cant compare em though.

Jakes Dad

You forget bike motors. Americans also can build small engines that produce. The 1200 h.p. 8 injector not running on pump gas 2.0 engine found in all GM mini pro stocks puts out h.p 1/4 mile at a times faster than 99% of the people posting here..

Reliable + h.p. try ever sprint car in America. Every from of motor sports in America.

NASCAR builds reliable push rod engines. The Japs are no match yet. Even filed, so many L's.


Those little Jap motors with all the H.P. is also horse p---.

GM build a 2.4 called an LD-9 engine. Who knows what it was in? Bad water pumps, bad oiling, a real junk engine. My experience was you could become a member of Club Si with a Chevrolet LD-9. You could offer to race any full interior, original factory engine, street tired auto or stick Honda. Could care less about h.p., within 500 miles of Dayton Ohio. You could do this for four years. Get removed from the web page 6 times. Facts are, one loss in 4 years. Driver error, got treeded.

H.P. is a great bragging point. HP will allow you to run more mph. There are hundreds of things other than h.p. to get a car from point a to b quicker. What is more important? So many h.p. per cuin, or something else? My vote goes for something else, but great topic.

nine-eight

iTrader: (7)

Bingo. this one hit the nail on the head. you can scream and rant and rave about your 100 hp/L 4 cylinder all day long. i dont care that it can make the same amount of power that my v8 can make N/A. the bottom line is this: if you get 500 hp from a 2.4 liter turbocharged motor, and 500 hp from a naturally aspirated 5.7 liter motor, the only possible advantage for a street car would be IF that 2.4L motor weighed less and had a smaller dimension than the 5.7 Liter motor. the 2.4L motor will be more stressed, get worse gas milage, have worse manners at low rpms, and in general will be more costly in the end. and ya know what? with the advent of the ls1 you now have a production motor that is smaller and weighs less than a honda 3.0L v6 motor. the 3.0 is more efficient, per liter. it puts out 240-260 horse. the v8 is less efficient but creates more power, in a package that is smaller and lighter. fully dressed these things weigh around 430 pounds. last v6 we pulled from a new honda weighed damn near 500-550.
heres just an interesting little sidenote for ya. some locomotive details. these motors are not power per liter- but they pump out tremendous amounts of power and they run for well over a million miles. the engines actually run straight water in the cooling system, so anytime the temperature will be below 32 degrees the motors sit and idle continuously. even in warm weather, the engines are more likely to be kept idling continously between trips than shut down. at full throttle, a modern locomotive will produce 4400-4600 horsepower at right around 1000 rpm at load. there is a certain model that produces 6000 horsepower. these are 12 and 16 cylinder diesel motors with tanks that hold around 4-5000 gallons of fuel. modern locomotives dont even use the diesel motor to apply force to the track. instead they run generators and alternators of sorts, depending on what kind of current they are built to use, ac or dc. this current powers electric motors at each wheel. the current produced from this massive diesel motor runs up to 1000 volts. this system delivers "tractive effort," or force to the rails in the direction of travel in thousands upon thousands of pounds. think of 27,000 KLPs of pressure. this is enough to move something as heavy as say a coal train, which can tip the scales at around 16,000 tons, fully loaded. the engine alone weighs 200 ton, or about 415,000 pounds.

gallardo259

how much of a role does # of cylinders/displacement really make? Does it change the necessary rpm to achieve hp? Ducati v-twins make nearly the same hp at lower rpm than i4's and are more streetable. On the otherhand, F1 cars distribute the displacement over more cylinders, wether it be 2.8l v-8 or 3.0l v-10, and make huge hp #s, and can rev past 20,000rpm(restricted to 19k), but are not very streetable or reliable for that matter.

On a different note, does anyone have anything to say about Wankle/rotary engines?

FieroZ34

iTrader: (1)

Well because of the level of tune that sportbikes are at, and the RPMs they turn, rotating and reciprocating mass is huge. That's why the V-twins don't rev as high as the 4s. First off, their pistons and rods weigh more because they are much larger. Secondly, even though the cylinder can, at 100% VE, pull in as much air as two of the I4 cylinders, in the real world it can't happen because the 4's heads flow just as much as the twins, despite the V-twin needing needing as much airflow for one of its cylinders as the I4 gets to two of its. (For the same power). Furthermore, since the 4s can rev higher, they can achieve higher VE, which means more power.

I disagree that the Ducatti is more streetable. Having ridden both Ducattis and other 1000cc sportbikes, there is no difference in streetability. As I said before, the 4s have plenty of low end. And with the introduction of dual stage fuel injection, and precise tuning, the power delivering is strong, smooth, and without hiccups (Unlike the old days of carbs). And even in midrange power, the twin doesn't even have any advantages. They are pretty even up until about 8,000rpm, where the 4s start to really wake up.

Secondly, your numbers are flawed. The Ducatti does NOT make as much power as any of the competing I4 squids. From www.sportrider.com, the 20006 999s made 139whp @ 10,000rpm, whereas every I4 squid made right around 160whp @ 11,500-12,500 rpm. And that 20whp is a HUGE difference in these bikes.

Because F1 distributes the displacement over more cylinders, that is where they get their HUGE rpm numbers, and consequently power numbers from. Same as the bike theory, they have much lower internal weights, and they take the same headflow and give it to smaller cylinders, which means higher VE.

Yah, actually

gallardo259

hey thanks for explaining it to me, and i like the rotary poster!! The Duc I was thinking of was an S4R (996 or 998 in 'Monster' form, naked chasis) that a friend of mine has that makes over 150hp, maybe it's not stock. So is it the ablility to put the power to the ground that the Ducati has, that makes it competitive in racing (WSB)?

FieroZ34

iTrader: (1)

I've got a whole bunch of those. They're pretty funny, even if not completely true...hehe

Your friend's bike must be modified a bit, because the highest power Duc is the one I quoted, the 999s. The racing part for sportbikes I'm not too familiar with, however I'm sure they give advantages to the V-twins, like perhaps a lower weight limit or something to that affect, because especially in racing, the advantage of having a 4cyl would be tremendous. Putting the power to the ground is much different in bikes than in cars. You don't really have to worry about wheelspin, because tthe tire is wide, made of great compounds, and all the bike's weight transfers on it upon acceleration. Thus bikes are far more likely to pull the front wheel up, which is the equivalent to a car spinning (Looks cool, but doesn't make you go fast). But the rider can shift his weight onto the front to help keep the wheel down. Also, I believe the racing bikes have traction control nowadays...Correct me if I'm wrong on that.

black_knight

iTrader: (1)

Not my point. My point is that you are concerned with weight, not liters as such. Focus on the words "as such." Fact is that while liters are sometimes a good predictor of weight, they are not always such. Especially in automobile engines with different configuration types.

I both agree and disagree. Inline configuration has some to do with it, but it is also because they are bike engines (i.e. small) that the proportion of valvetrain size to cylinder block size is different.

Sometimes. Not always. So it's misleading to say that less liters necessarily means a smaller/lighter package because that is just blatantly false. And the idea that HP/L is useful depends on that false assumption.

Huh. Well, you learn something new every day.

Nope. HP/size+weight is very important. They just use liters as shorthand but it is misleading. People should say what they mean.

Now it's my turn to correct your info: The LS2 weighs about 15 lbs less than the LS1. The LS7 weighs about 10 lbs more than the LS2. But those have more to do with the manifolds and accessories. The engines weigh about the same. And you can stroke any of them while keeping weight essentially the same. So NO, displacement does NOT equal weight. Not always. Therefore, you should not talk like it does. If you mean weight, say weight; not liters.

black_knight

iTrader: (1)

Dude... you completely misunderstood me. I wasn't talking liters as opposed to cu inches! (that was some other guy and he was kidding!) I was talking liters as in displacement! Please re-read my post with that in mind...