So I saw a hayabusa put down 215 to the wheels with a 1400cc stroker kit, cam, ported head and I was just wondering why we can't get a 1600cc to put down that much power on pump gas. I know there is less drivetrain loss, but I mean dang, how many b16's even break 180(dynojet)?

I mean what do guys really think is holding back these motors? Too small of a bore? Not enough rpm? Head doesn't flow enough? Or is it all in cam timing?

Also, how do street bikes turn such high rpm, but you never see one burning oil?

I've wondered this forever, just finally decided to post it. Looking forward to seeing what you guys think

 

motor design, its pretty close to a f1 motor, if you look at the graph all the power is pretty near the redline w/o much tq. lond rods+short stroke= higher rpm breathing. plus the have itbs, and pretty low rotational mass (the reason for no tq)
put that motor in a car and it might not perform as you might expect.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2000ekhatch &raquo;</TD></TR><TR><TD CLASS="quote">motor design, its pretty close to a f1 motor, if you look at the graph all the power is pretty near the redline w/o much tq. lond rods+short stroke= higher rpm breathing. plus the have itbs, and pretty low rotational mass (the reason for no tq)
put that motor in a car and it might not perform as you might expect.</TD></TR></TABLE>

low torque can be partially fixed with a steep final drive, which you would need anyway b/c of the high rpm you would be capable of turning.

I'm sure that motor wouldn't perform that great in a car, but I mean it's only 1400cc. I'm just trying to find out how they make more power than b16's(even one's with ITB's) with a solid 200cc less displacement.

So why do you think they don't blue smoke like b-series are notorious for?

 

Long rod = low piston speed

low piston speed = less friction = less heat which ultimately leads to less oil consumption- this would be my guess. But it is just a guess.


Modified by asubennett at 12:48 PM 6/24/2004

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by asubennett &raquo;</TD></TR><TR><TD CLASS="quote">Long stroke = low piston speed

low piston speed = less friction = less heat which ultimately leads to less oil consumption- this would be my guess. But it is just a guess. </TD></TR></TABLE>

long stroke=high piston speed

I know that most street bike engines are way oversquare, so are you saying that the short stroke reduces piston speed which is easier on the internals? Either way, they still turn wayyy over 10k.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lube &raquo;</TD></TR><TR><TD CLASS="quote">So I saw a hayabusa put down 215 to the wheels with a 1400cc stroker kit, cam, ported head and I was just wondering why we can't get a 1600cc to put down that much power on pump gas. I know there is less drivetrain loss, but I mean dang, how many b16's even break 180(dynojet)?

I mean what do guys really think is holding back these motors? Too small of a bore? Not enough rpm? Head doesn't flow enough? Or is it all in cam timing?</TD></TR></TABLE>

Bottom line is engine speed. The busa's don't create much torque, but when your turning 14,000-16,000 rpm or whatever those things turn, and your head allows you to breath effeciently up there, then you are going to produce some serious power, bottom line. The lack of lowrpm torque trying to move a 2200lb+ car around would simply be undrivable.

You get a B16 to breath effeciently at 15,000 rpm and you will be pumping out 240whp easy.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BryanPendleton &raquo;</TD></TR><TR><TD CLASS="quote">


You get a B16 to breath effeciently at 15,000 rpm and you will be pumping out 240whp easy.
</TD></TR></TABLE>

yea, and you wonder why bike motors have short lives.. you gotta rev the **** out of them

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BryanPendleton &raquo;</TD></TR><TR><TD CLASS="quote">Bottom line is engine speed.</TD></TR></TABLE>
I agree most definitely. You have to be able to maintain a reasonable torque curve and VE that high up and rpm will do the rest. Everything else mentioned is in support of that bottom line.

 

Yeah, when a bike only weighs a few hundred pounds, it's engine can get away with ****-poor low-rpm (read: &lt; 6,000 rpms) performance & still be plenty quick down there. So they sacrifice lots of low-end for a ridiculously redline & top-end power. Can't get away with that in a car (as much).

Another factor is that a bike engine doesn't need to last 200,000 miles like a modern car engine.

 

if you ever have the chance to see in side any sport bike motor there awsome....*** stated above there almost f1 engines...i had a 88 600 nija and rebuilt it ..i twas like looking at a small honda motor ....but seriously here ...they can idel at 1000 to 1500 rpm with no problems (cuse the short stroke)the cams are pretty big considering the size of the motor .....(thats why they make no low end power ...they all run stupid compression..usually over 12:1...combine that with lots of fuel and a ton of revs (plus awsome breating heads and ITBS)youve got your self a powerfull motor up high

 

A lot of the principals and techniques that are now popular commonplace in Honda engines have been long integrated into sport bike engines (and sometimes from the factory).

Look at the clover leafed combustion chambers, ITB's, contoured piston domes, strutted and coated piston skirts, etc. on the new 600RR and ZX-6RR. See the new Sport Rider magazine featuring the most recent 600cc shoot-out that introduces the new ZX-6RR. The new ZX-6RR has a class high 13.5:1 compression ratio while everybody else is still at 12.5:1 to 12.0:1.

It's nice that bikes in the class have switched to EFI. I like EFI.

The gearing and tall rpm band helps too with having such a small motor and low torque curve.