Does anyone remember what the stock rod to stroke ratio is on the h22 motors thanks

 

1.58

https://honda-tech.com/zerothread?id=549372

 

isn't the optimum rod to stroke ratio 1.75?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jdmcivicferio &raquo;</TD></TR><TR><TD CLASS="quote">isn't the optimum rod to stroke ratio 1.75?</TD></TR></TABLE>

yes, but not every engine has it. B20 is worser than 1.58.

B16 is the closest of all the Honda Engines.

 

so technically if you put a deck plate and got longer rods, the motor would work my effeciant

 

yes.

 

R/S of f20?
And you can replace the rods and crank of the h22 with the f20 ones, and have the same R/S ratio right?? ie deck hieght is the same. Thats my next mod. But what are the rod legths and crank stroke of the f20??

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LudeHatchH22a &raquo;</TD></TR><TR><TD CLASS="quote">R/S of f20?
And you can replace the rods and crank of the h22 with the f20 ones, and have the same R/S ratio right?? ie deck hieght is the same. Thats my next mod. But what are the rod legths and crank stroke of the f20??</TD></TR></TABLE>
The F20 has a shorter stroke (88mm) & longer rods (145mm) - a r/s ratio of 1.648:1.

 

yeah good luck finding f20 crank and rods

 

It is much more complex that just being more efficicent by running longer rods, having this lower rod to stroke ratio allows for a high vacuum pressure in the first 90 degrees of the intake cycle which which is good for low rpm power, but of course this same speed occurs during the first 90 degrees of the combustion cycle, in fact is it so fast that towards the higher rpm range the speed of the piston will actually outrun the flame front so your power will die off not to mention the greater friction because of the loads on the side of the cylinder walls and bearings due to the piston wall to rod angle,

however going to a longer rod will not magically increase the efficiency of your engine because the piston speed will be lower and it will not create a quick vacuum which result in a loss of bottom end power due to reduced air velocity but you will see a large increase in top end power back the piston will linger at TDC for longer because of the lower piston speeds which will give you higher cylinder pressure for a longer period of time and it will also reduce the load on the cylinder walls and bearings which will enable you to use a piston with a smaller skirt which will let it be even lighter and have less friction, there is alot of other modifications you would have to make to take full advantage of this top end power, for most people I think it would be best to stick with your stock R/S

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by satan_srv &raquo;</TD></TR><TR><TD CLASS="quote">yeah good luck finding f20 crank and rods</TD></TR></TABLE>

Exactly what he said. Better bet is to buy a whole F20B longblock or swap.

 

Why doesnt anyone ever get custom rods/pistons to change the r/s ratio??

 

It's a big expense for a marginal improvement. The most you're gonna be able to get on the stock stroke is about a 3 or 4mm increase in rod length - r/s ratio goes from 1.58 to 1.62 . . . whoopee.

 

haha well thats a big improvement