I'm afraid I don't understand the "shorter connecting rod" business.

See if I have this straight. If we assume that the engine has been stroked and not bored, it means that the piston must travel a further distance within the sleeve in order to generate additional power.

But if you shorten the connecting rod, aren't you just defeating the purpose of lengthing the stroke, and ending up back where you were in the first place?

 

You shorten the rod, which lengthens the piston stroke - this instantly enlarges the volume of the combustion chamber. More fuel and air can be ignited per compression stroke et voila - more energy is produced.

 

Not necessarily softer in a negative way - this is classic European tuning - relatively soft springs, big tires, very sophisticated shock damping - it makes for better handling on real-world roads as opposed to billiard tables, and the fatter tire patch should ensure lateral accel stays good. It may not be all things to all people, but a blanket condemnation based on one word is a bit over the top...

 

i wish everyone would just kick back and stop speculating...just wait til the damn car comes out..(just look at Mazda,AFTER they release the car they realize mistakes on the numbers they put out)..lets just see what happens.just my .07cents

 

Sweet!! Wonder if I can swap some of my 02 parts for the new 04 parts......

 

hey guys, my name is sara (skreemn's daughter) and i'm a sales consultant at a honda dealership. these pics are 100% real, we just got our MY04 Facts Books from honda and the info in there matches these pics. the new S2 is 25lbs heavier (probably because of the new 2.2 and the 17 inch wheels), .6 inches taller and now has 161lb.-ft. of torque. however, the largest gain of torque from the 03 was 15 lb.-ft. the hp is still 240 (published) but Honda claims that you actually gain a little horsepower thru the powerband that they decided not to disclose for some strange reason. the gear ratios have changed a little bit from last year also. they made the doors skinnier for .5 inches of increased elbow and shoulder room yet the passenger volume was decreased. the stabilizer bars are shorter to compensate for the larger wheels, about 2 inches in the front and 4 in the rear. you now also get larger brakes in the rear too, increasing the previous 11.1 inch rear brakes. new color: rio yellow replacing spa yellow and now you can get the red interior with the new yellow.

this has probably already been told to everyone but i didnt read all of the pages
thanks for reading.


oh, and no MSRP from honda yet.
-sara

 

Hi Road Rage,

No offense here but you're a bit confused on this one. The length of the con rod has "nothing" to do with the stroke. The length of the stroke is defined only by the crankshaft. The farther the distance from the centerline of the crank to the centerline of the crankshaft throw (the part the con rod is bolted to), the longer the stroke will be. Also, keeping the stroke the same and shortening the con rod doesn't increase the volume of the cylinder. What is does do is lower the compression ratio and that's going to reduce potential power output, not increase it.

What Rick and I were discussing is the ratio of the length of the con rod to the length of the stroke. The shorter the con rod, the greater the angle it much achieve when the crankshaft throw is 90 degrees from top or bottom dead center. Keeping this angle to a minimum is preferable but that can lead to an overly tall engine at it's extreme so, as with all mechanical things, some compromises are made.

Assuming that all Honda did was put a different crankshaft in the S2000's 2.0 engine without changing anything else, the longer stroke would be pushing the piston into the cylinder head or compression ratios would go through the roof and we'd be driving the first (that I know of) diesel powered sports car!

So, they shorten the con rod so that head clearance and compression ratios are maintained as before. The result is an increase in torque because the longer crank throw offered more leverage to turn the crankshaft and a decrease in potential max rpm because of increased piston speeds (for a given rpm) and, as Rick pointed out, an increase in certain engine stresses due to the increased angles experienced by the con rod during the cranks rotation.

Hope this made some sense,
Drive Safe,
Steve R.

 

Really??

So now we can get a Ronald McDonald car but not Monte Carlo Blue?

American Honda...you guys are on top of things.

 

Just in case Honda is reading this... this is SARCASM.

 

[QUOTE]Originally posted by Intrepid175
[B]Assuming that all Honda did was put a different crankshaft in the S2000's 2.0 engine without changing anything else, the longer stroke would be pushing the piston into the cylinder head or compression ratios would go through the roof and we'd be driving the first (that I know of) diesel powered sports car!