Assuming you have two identical engines. Only difference being one has a rod length of 137.9mm versus the others of 137mm. Pistons are the same minus the changes needed to run the slightly longer rods.

What kind of changes on the dyno would you see?

 

Is this with keeping the same wrist pin location?

Id think the longer rod would slightly sideload the piston less so youd free up some friction at higher rpms. I think this would mean slightly more power up top(due to less piston sideloads) than the short rod engine...
Whatever it does, i imagine it would be very slight...
Thinking about trying it out?

 

short rod has 21mm
long rod has 19mm

Thinking, yes.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aquafina &raquo;</TD></TR><TR><TD CLASS="quote">short rod has 21mm
long rod has 19mm

Thinking, yes.</TD></TR></TABLE>

Pin DIA or compression height?

 

DIA

 

Can you give us a little mre on the set-up? IDK if your talking about using a smaller pin in the same location or pushing the pin up in the piston 2mm. Sounds very interesting. Are you looking into the GX piston and Rod?

 

Rod length is alot less important than people make it out to be. Unless you are talking about durability problems from a real long stroke and stock length rod. Otherwise, the 0.9mm won't even show up on a dyno nor IMO will it affect friction/longevity much if any. I think it will fall within the margin of error on a typical dyno--you won't notice it. F1 cars and sport bike run r/s ratios of 2:1+--that is an extreme example to allow the motor to live at elevated rpm without losing too much power to friction. Small amounts like the difference between 1:52 and 1:55 are so small as to be negligible.

 

good point

 

79mm
12.5:1
RM rods

 

Rocket makes custom rods?

 

No.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aquafina &raquo;</TD></TR><TR><TD CLASS="quote">Assuming you have two identical engines. Only difference being one has a rod length of 137.9mm versus the others of 137mm. Pistons are the same minus the changes needed to run the slightly longer rods.

What kind of changes on the dyno would you see?</TD></TR></TABLE>

You would see Zero ............

Dyno sheets would lay over each other ...

The LS rod to the .137 longer eagle You cant see much on that ... 1 and 2 in the upper

 

I'll take 1 and 2 since it is cheap to have the rods machined.

 

Cylinder head flow &gt; Rod Length

 

Robert will be taking care of that.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Aquafina &raquo;</TD></TR><TR><TD CLASS="quote">Robert will be taking care of that. </TD></TR></TABLE>



That **** needs to return my emails.

 

Give him some time, he's busy developing stuff.