This is really bothering me!!!!!

A friend and, i were discussing this point: How does the YZF 450 motor make about the same HP as a Raptors 660 motor? It is 210cc smaller and, has less valves yet it is on par w/ the HP?

Is it that the 660 motor has no "massaging" done and, the 450 motor does? I know you can bore and, cam and, port the 660 for more power but the 450 already has equal power so you can do these things to the 450 (i'd think) as well and, now it is even again.. With the 450 equalling the 660 power the 660 is always a step behind.. Is it that there is a lot of room for tweaking the 660 motor and, most of the room for tweaking is already done in the 450? Is it that the 450 is ported to the hilt and, has a maxed cam and, the 660 is built way more mild? Is the 450 making the power w/ higher compression? Is there a hidden "De-tuner" in the 600 motor that we don't know about?

I just don't understand how to recently new motors 3 years on the Raptor Motor and and, few months on the 450 and, they make nearly the same power while the 450 is nearly a 1/3 smaller? They both run pump gas, both are 4 stroke, why shouldn't the 660 be a 1/3 more powerfull?

Also why is the 450 motor so much more power full than the other 400 class machines? Is Yamaha just a way better engine designer than Suzuki, Honda, Polaris (500 Predator)? What are the differences in the YZF 450's motor and, say a Z400? I saw a article in DW and, the Stock 450 still beat a Z400 punched out to 440 and, hightened compression and, porting??? This is baffling to me!

I think this is cool because I'm a Yamaha fan but why didn't they do the "Same Technological Advances" on the 660? If I/We can find out what sets the 450 motor apart from the other motors out now we could have a YFZ 450 motor + 30% more power through size advantage.

Another example of this is Ricer Cars like Acura get 300+ hp out of a normally aspirated 3.2 liter engine and, there are tons of V8 motors out there that can't touch those #'s. I realize they have higher technology in the motors such as induction changes and computers but, those are way more advanced then our Quad motors.

Why is it that all the performance Co's make Big Bore Kits when the size obvoiulsy doesn't matter.. Is the Real Answer making a 660 into a 686, 707, 727 or, 8,000,000???? DON"T THINK SO. I think we need some Real Race Engineering Co's to analyse the internals more and, Skip the Bore it to the Moon Theory! Yamaha has done the R&D for us, we just need to apply the same priciples to the other motors. It is pretty obvoius that there are ways to make serious power w/o making the motors bigger, super high compression and more unrealiable than a factory Rocket like the 450!!!!

Can anyone clarify this?

 

The YFZ comes from the factory with higher compression (11:1 versus 9.6:1) and better porting. They spent ALOT more R&D on the 450 engine than the 660 becuase of its use in the dirt bike market. Also, if you don't think bigger is better, I will have to disagree. Bob Craycraft builds amazing Raptors. Guess which one is the fastest he has built? A 727! Know why? Because if two engines have the same great porting, cam, carbs, high comp, etc., the one with more displacement WILL make more power. I use to not be a firm believer in this but now I am. Of course I have my big bore in a bottle....[img]i/expressions/face-icon-small-wink.gif[/img]

Also, on your thoughts about car engines. The S2000 produces 240 hp out of 2 liters, or 120 hp per liter. The highest per liter HP output of any N/A production car (I think, it may have been passed here recently) Very impressive, and the car can be had for around $25K. However, to build a big-inch V8 to those numbers is very costly, though it can be done. In a Hot Rod article I was reading, they were marveled by a 565 ci V8 that made 1050 hp on pump gas. While those are awesome numbers, that is only 115 hp per liter, and the engine cost around $40K to have built! (don't quote me on prices, but I know it was outrageous). But still, which is more reliable, a 500 hp 4 cylinder, or a 500 hp big block? Hopefully you see where I'm coming from.

By the way, I am in no means trying to be a jerk, just like to have a respectful debate every now and then.

 

Well there's lots of reasons that the YFZ makes more "Horsepower" than the Raptor.

Horsepower is a mathematical calculation based on torque and horsepower at a particular rpm.
2 engines may make the same horsepower but can be considerably different in size.

The Raptor is a larger displacement engine...obviously. But... it is tuned to be more of a torque based engine... low rpm power in general

The YFZ is designed to be a high rpm engine and has a considerably higher rpm range to make it's power than a Raptor does.

Remember.... these are two totally different engines. If you would like... I can look up the horsepower figures and let you know how to get "Horsepower" figures based off of torque at a particular rpm.

 

One has to look at other things except size of the motor. One major difference between a raptor and the YFZ is the RPM they make their max HP. Raptors make HP at much lower RPM than a the YFZ. Stock Raptor produces max HP at about 6000 RPM, the YFZ at 8000. If you have the right motor, intake and exhaust setup right, you can make double the amount of HP that the YFZ currently have. One thing though. It will not make double the HP at the same RPM, but more like at double the RPM it currently makes HP. Take a 600 CC road bike for instance. About the same size as a raptor. How much HP do they make? Close to 100HP, but at 12 000 RPM, not like a Raptors 6000 RPM max HP.

Torque on the other hand is different. Bigger motors make more torque. So here size does matter. Don't think because you have a bigger motor it will make more HP than a smaller one.

If you like to learn more and what to play with things, read up about volumetric efficiency. See what the effect the cam, compression, air density and size of the motor have to do with HP.

I have a small excel spreadsheet that I made so if your interested PM me.

 

Some good points.

I don't want to turn into a this XXX Company make the Greatest, bestest, fastest big bore bla bla bla...

I just want to understand the hole idea that a 450 make as much power as a 660 because WHY?

The 450 uses pump gas so, is it safe to say that if you put a 11:1 (as opposed to 9:6:1) piston and, do "Better Porting" (450 Like) in a 660 Raptor it will make a 1/3 more Hp and, still be reliable and, run on pump gas?? Why doesn't everyone do it?

After all unless you make the Raptor 660 power plant have the (Mentioned above) HP to Engine Size Ratio as the 450 you will always be behind in the performace search!

Making the 660 bigger doesn't help cuz you could make the 450 bigger, putting in a 14:1 piston doesn't help cuz you can always do it to the 450 and, now your equal again. Your always on the short side!

I guess i'm saying how can you make the 660 have as high of HP Per Given cc as the 450. And, why isn't this the first thing performance people look at??

 

You're almost trying to compare apples to oranges here. You're talking about two totally different engine designs here. If you made a YFZ motor that was bumped up to the size of the Raptor (in every aspect) then you would be talking about some serious power. Other than that... you can't expect to get the superior power out of an engine that was not designed to make it!!

 

Ridley, sounds like you know a bit about this. And, I understand they are different.

That said, i wasn't saying i wanted a 80 HP Rappy. Just what would it take to get as close to the Power Ratio as you can to the Performance per given engine size of the yfz 450 to the 660.

The 450 is 32% smaller than the 660 so ... The 450cc gets you roughly 35 HP (for example), shouldn't 660 with simalar design get you 32% more = 46.2???? If you had a 450 design that was 660cc it should be 30% more powerfull... Being that that are different could you take the principles that make the 450 better and, apply them (((as much as you could))) to a 660 to get the Power to size ratio better???

I don't want a million dollar R&D for my rappy motor. I just want to know what makes the 450 more efficient so i can try to make my near it's power for it's size

Like I said above: If you equal the compression ratio on the piston on the 660 to 11:1 like it is on the 450 and, port it better (simalar to the 450) it should be better right??????

 

Good topic guys.

About the Smaller engines making as much hp as the larger engine's

Its easy to make HP out of a small engine, the first 50 hp is Easy to make, but when you start talking about BIG HP #'s the YFZ will top out at around 60-65hp period, it wont matter how big you bore it. But 60hp out of a FAST reving engine wil be like 80hp out of a slower big engine like the rappy. It is possible to get an honest 90hp out of a rappy(thiers your 1/3 power #)

But it is pretty much impossible fro a "big" displacment motor to ever match the Power ratio of a Small diplacement motor simply because the bigger the Componants are the more things like FRICTION,GRAVITY,and VELOCITY come into play. its not fair to compare Small engines to big engines in those terms.


However, In the end.....BIGGERisBETTER[img]i/expressions/face-icon-small-happy.gif[/img]

 

Ridley-
Well, I don't think you understand the point fully. The point is not for my Raptor or any other. It was more like a why not for any bike and, why are they all not done this way? Rappy's, Z400's, 400ex's, Predators, V Force 700's engineering is all inferior...! Must be a reason?

I will it admit it is was also to see if there are ways other than boring to get more power. And, why wouldn't everyone do it if there is rather do something as dumb as boring out your bike. Just to get a few more cc's when you already have 660 to work w/ and, making it an off size and, unreliable?!?!?

I liked all your points UNTIL you started in w/ the you can only get so much w/o boring... IF Size doesn't matter on the HP if it is engineered right?? IF 210cc difference (660-450) doesn't make a difference than adding 67cc shouldn't either to go to 727. That makes 0 sense. It makes less sense to say that X,Y,Z will give you 50-55HP but, if you go to the "Holy Grail" 727 kit you'll be at 70HP. So the hole therory of engine building you stated goes out the window when you claim 15HP out of 67cc bore??? Does the size matter or not then?

There is a lot more to those kits than boring and, i'll bet the boring has the lest effect but makes the Kit builder the most $ on Labor and, Parts!!!!!

and Ridley??,,,, It doesn't sound like from my post that i have the money? You can see my bank acount through my post? What does that have to do w/ an efficient high HP motor discussion anyway? I could go get a 727 tomorrow if it was reliable, i could ride it for 8 hours straight As i do at the dunes and, wasn't a drag only/one pass let it cool down, drive to NASA to get alcohol for fuel, hole in my pocket. Because I don't like to throw $ out the window............. In case you wanted to know.

I don't want to flame... I just wish we could get answers from some one like a Yamaha Engineer or, a Cumbustion Engineer at least. Something is not making sense..

 

Their are many ways 45 hp can be delivered. the YFZ motor delivers its hp in a much smaller Power band, which combined with its light wieght , close ratio tranny and wieght tranfer is a fast accelerating machine. a 45hp Rappy has more linear power, but wont accelerate as fast as the YFZ because of its broad power band , long trail gears and additional wieght.




As far as MOTOR agianst MOTOR, ask John Force what he would prefer to biuld! You wont ever see a 1.4L Mazda engine powered Dragster run 4.60 in the 1/4mile.[img]i/expressions/face-icon-small-smile.gif[/img]




BIgger.