.....quoted here to get answers. The above is not my statement, but I am now curious.....

 

Yes they would have made more torque with a longer stroke, but they couldn't really recommend a 9000rpm redline as a result.

 

The S2000 got a R/S ratio of 1.81

 

pretty close to an ideal ratio of 1.75

 

isn't the B16A2 1.74???

 

yep...it's a motor with ideal bore/stroke ratio.

 

please explain where this ideal 1.74 Bore/Stroke ratio came from - and who says its ideal

 

Check out http://www.theoldone.com/archive/
.
But Ideal.. What is ideal anyways?
And what's not?.. hmm... ..

 

ideal means a perfectly square bore to stroke. When the bore to stroke is ideal, the stresses on the crank/rod/piston assembly are the lowest.

 

we are talking about the rod to stroke ratio. a square bore and stroke means they are the same measure, like 86mm x 86mm like the K20. oversquare means a bigger bore than stroke, undersquare longer stroke than bore. THERE IS NO ideal bore to stroke ratio: F1 cars have a bore/stroke ratio over 2:1, and are designed by geniuses from the ground up to be the highest NA ouput engines in the world. The Honda Insight, the most efficient car in the world, has a bore to stoke ratio of 0.88:1.

Higher revving MODIFIED engines have shorter strokes to allow lower piston speeds and acceleration with longer con rods, and have larger bores to compensate for the displacement loss without significantly increasing reicprocating weight. Bigger bores allow bigger valves for better VE at higher engine speeds.

 

its rod length to stroke dimeter, the bore has nothing to do with it...if you bore out a b16 to 84mm, you get almost 1.8L but still maintain the 1.75 r/s ratio.

 

Yes i know....but he was talking about bore/stroke ratios, and I was talking about the insignificance of them.

I mentioned MODIFIED engines that are de-stroked (allowing longer rod) and bored to compensate displacement for the shorter stroke. I was describing the total engine package.

 

With a higher R/S ratio you get lower crank to rod angles(good for motor as less side loading on piston results in less wear), and high rpm breathing capability improves.

 

can u bore a b16 out to 84 mm without resleeving it?

 

Hell no! 82mm bore MAX without resleeving... That's a thin-walled cylinder too... Don't even think about FI on it then...

Most people just keep the b16 head and use the b28 block, route oil lines for vtec, and done!