does it?

 

It would effect piston dwell, but I think speed would be a derivative of stroke. Im too lazy to think about it, but there was a graph posted somewhere about pistons speeds on the various engines....

I dunno, Im thinking myself into a circle, someone chime in and correct me.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by notstock93 &raquo;</TD></TR><TR><TD CLASS="quote">
I dunno, Im thinking myself into a circle, someone chime in and correct me.</TD></TR></TABLE>

u telling mee bro? geesh


Ed-

 

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

u telling mee bro? geesh
</TD></TR></TABLE>

Que?

Anyway, I think max speed is stroke based, but mean pistons speed is influenced by rod/ratio.

 

Piston speed would be increased. If the piston dwells longer at the top, it has to go faster in the middle to complete the cycle at the same time. Kind of like getting a head start in a race but finishing the race as the exact same time as your opponent. The guy that left last had to go faster.

 

piston acceleration will be affected.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WestCoRacer &raquo;</TD></TR><TR><TD CLASS="quote">Piston speed would be increased. If the piston dwells longer at the top, it has to go faster in the middle to complete the cycle at the same time. Kind of like getting a head start in a race but finishing the race as the exact same time as your opponent. The guy that left last had to go faster.</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mmuller &raquo;</TD></TR><TR><TD CLASS="quote">piston acceleration will be affected.</TD></TR></TABLE>

Not quite and yes, but not by much in either case, barring really poor designs. A longer rod approaches the theoretical sinusoidal motion for the piston. A shorter rod resides at BDC longer and has slightly higher speeds and acceleration. Longer is better.

 

After tdc the long rod piston speed will be gained slower than a short rod engine in proportion to crank angle.
The short rod will have slower accelerating pistons speeds away from BDC; but piston speed will get faster the higher up the stroke compared to a long rod.

 

Yes, a B16's piston is going to be slower than a 6 cyl Turbo diesel 18:1 cr engine with a r/s of 1.0 or less.

 

if we agree that it increases acceleration, and speed is a part of acceleration then it does in fact increas max speed of piston travel.


Ed-

 

there was a post a while back about long stoke motors ect. here take a look tons of good info from very good people in the honda game. https://honda-tech.com/zero...age=1

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ModenaTwinTurbo &raquo;</TD></TR><TR><TD CLASS="quote">if we agree that it increases acceleration, and speed is a part of acceleration then it does in fact increas max speed of piston travel.


Ed-</TD></TR></TABLE>

I already answered that. The theoretical shortest rod length equals the stroke length. In that case, the piston travels from TDC to the "position" of BDC (not the actual BDC) in just 90 deg. of crank rotation instead of 180 deg. For 180 degrees of the crank rotation, the piston would not move at all. Therefore, it would accelerate and travel twice as fast as the theoretical infinite rod length, which has sinusoidal motion.

A longer rod is better.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dogginator &raquo;</TD></TR><TR><TD CLASS="quote">A longer rod approaches the theoretical sinusoidal motion for the piston. A shorter rod resides at BDC longer and has slightly higher speeds and acceleration. Longer is better.</TD></TR></TABLE>

 

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

I already answered that. The theoretical shortest rod length equals the stroke length. In that case, the piston travels from TDC to the "position" of BDC (not the actual BDC) in just 90 deg. of crank rotation instead of 180 deg. For 180 degrees of the crank rotation, the piston would not move at all. Therefore, it would accelerate and travel twice as fast as the theoretical infinite rod length, which has sinusoidal motion.

A longer rod is better.

</TD></TR></TABLE>

ahh
you the man bro thanks for the explanation


Ed-