I just dont get it!

[sportbikeryder]

its all in RPM difference . example in lay terms , alot of semi trucks have 700 hp motors ( at 3000 rpm ) but could not run anywhere close to a 700 hp ( @ 7000 rpm ) rat motor in the same car weighing the same . its all about rpm. thats just one aspect and does not apply to every motor .

Really? Alot of trucks have 700 Hp? Must be a bunch of Yuppies with too much money ordering trucks with way too much power where you live

Why would it not run as well? It may run BETTER since it has a power band that is usable rather than peaky.

Power is power. Most bikes / cars do not have a transmision capable of holding the engine at its peak power though, rather have to move through a set gear spacing. This is why snowmobiles work so well with a CVT style clutch as they keep the engine right in the power band.

[craigntx]

I understand the rotating mass ..etc I just dont see why the Busa motor being so much larger and the cylinder head flowing more(I'll check on the velocity ,but Im sure (Busa)it has more and the #' arent close) want make more HP ?? Take a 500 inch big block (Built,good heads..etc and a 350 Built ...etc Theres no comparison in HP ...

Guess i'll just sell my busa and get a zx10...LOL

when my '07 busa was stolen (my 3rd busa) i got the zx10.
not dissapointed one bit

[O.T.]

Really? Alot of trucks have 700 Hp? Must be a bunch of Yuppies with too much money ordering trucks with way too much power where you live

Why would it not run as well? It may run BETTER since it has a power band that is usable rather than peaky.

Power is power. Most bikes / cars do not have a transmision capable of holding the engine at its peak power though, rather have to move through a set gear spacing. This is why snowmobiles work so well with a CVT style clutch as they keep the engine right in the power band.

This is Texas if you don't have a 700hp truck your going to get drug. A lot are in the 10's at the track.

Then again with the 700 hp engines the gas is going to be a lot lighter than a diesel.

[sportbikeryder]

Why would you want 700 hp in texas? Are there even any hills?

[speed]

well we have everything in texas . maybe the mountains are not quit the altitude but the grades are just as steep . 700hp @ 3000rpm is not the same as 700hp @ 7000rpm . the reason up port ur head is to gain rpm . anybody can build rotating assy. with big cubic inchs but good port work on a smaller motor will go as fast or faster because of rpm . It is better to make torque at high rpm than at low rpm, because you can take advantage of *gearing*.
RPM IS THE DIFFERENCE


Torque * RPM

------------ = Horsepower

5252

[speed]

Torque x RPM divided by 5252 = HP

[Hit Man]

hp = torque x rpms/ 5252. Big motors dont need to turn that many rpms to make the same hp. An all out 347ci can make 900 hp @ 9500 rpms. If you want 900hp but less wear and tear build a 557 ci and turn it to 6500 rpms with less compression. Spin a 557 to 8500 rpms and it will make well over 1000hp with the supporting parts.
The 1000cc motors are race motors from the factory and have radical cam profiles compared to sport touring busa engines. A busa can make the same power at a lazy 9800rpms. Build both motors with the same compression and the same target rpm range (9800) and it won't even be close. Smaller motors must work harder to reach the same hp #s.
This is all in theory and relative to the combinations. A 1.5L f1 engine can make 900hp, but @ 19,000 rpms.Build a 1397 just as radical as a 200hp 1000 and it will make more than 200hp. A 200hp 1397 is built for longevity not balls to the wall racing. The torque should help it run a good # with less gear. 200hp 1000s can't leave any stone unturned and must use rpms to make power with less mechanical advantage (displacement). Most people wanting a hp number would start with a larger engine for cost reasons.

[sportbikeryder]

. It is better to make torque at high rpm than at low rpm, because you can take advantage of *gearing*.
RPM IS THE DIFFERENCE

Horsepower is Horsepower dude.

You are thinking about torque. A harley that makes 120 ft-ls torque verses a usa that makes 120 will have MUCH less power than the busa. You can make whatever torque you want with gearing. You can't make horsepower. If you could make the horsepower at a very low rpm. you woudl be better off just from a gear efficiency standpoint as you could run single or double reduction instead of triple (typical sportbikes use triple reduction gearing, primary, transmission, and final drive).

If you build a 170HP harley motor and a 170 hp busa motor and run them down the track with the same total weight, they will both trap at roughly the same speed provided they are setup with the right gearing (minus the aerodynamic difference).

[speed]

well said HitMan . Sportbikeryder u dont have a clue ! 600's are half the size of most harleys and make no torque by comparison . which one is faster ???

[O.T.]

well said HitMan . Sportbikeryder u dont have a clue ! 600's are half the size of most harleys and make no torque by comparison . which one is faster ???

And which one is heavier. Weight is the factor in that race.

[sportbikeryder]

well said HitMan . Sportbikeryder u dont have a clue ! 600's are half the size of most harleys and make no torque by comparison . which one is faster ???

The 600...and if you gear it, it has the same or more rear wheel torque as a harley. You can change gear ratio's all day on a harley and it won't have the same horsepower as a 600....that is what I am saying.

BUT, if you build a 105 HP harley prostreet it will run the same as the 600 at the same total weight.

You cannot change horsepower with gearing, but you can change rear wheel torque to whatever you want.

[Hit Man]

Gearing gives mechanical advantage to low torque engines like gears on a 12 speed bicycle, but a 600 can't make 120ft lbs of torque. The time measured between 1500rpms and 16,500rpms will be storter if you were to clock it in seconds on a geared bike.Less torque needs more gear, more torque needs less gear, because it will hit the limiter too early and "nose over".
Weight is another story, it will take a lot more power for that harley to mph with a 600.

[eeyore]

just to sound in on a few basics

Torque is generaly a end result of displacement

Torque is Measured

Horsepower is caculated

HP = rpm x T(torque)/5252(constant)

Summery, the smaller displacement motors making the same HP are simply doing it at a higher RPM

[kiwi]

The 1000 is probably pulling 2000 rpm more, which will go a long way in compensating for its lack of size.