6" vs 5.7" rod for 383?
Le Mans Master
Joined: Oct 2004
Posts: 5,841
Likes: 19
From: CLT, North Carolina
How much your piston weighs and the location of the ring package will make more difference than long vs short rods. If you did a back to back change in rod length (including pistons of course, all other things being equal) and graphed your results it would be very hard to see the difference. Makes better bench racing claims than providing actual gains.
Regards, Greg
Regards, Greg
Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
Originally Posted by rodj
But note a gap in suitable ratios between 9.8 and 11+ for 64cc heads which are some of the more common aftermarket chamber sizes used.
http://kb-silvolite.com/downloads/catupdate.pdf
http://www.probeindustries.com/Pisto...hev_383_ft.htm
http://www.probeindustries.com/Pisto...v_383_dish.htm
http://www.probeindustries.com/Pisto...v_383_dome.htm
Melting Slicks
Joined: May 2001
Posts: 3,270
Likes: 26
From: Winchester VA
Cruise-In V Veteran
Originally Posted by CFI-EFI
I have an engine with 5.85" rods. It has a 4.00" stroke and the oil rings do NOT encroach on the piston pin bores.
RACE ON!!!
RACE ON!!!
JE told Crower in order to get the CR I wanted and to have good sealing properties, we needed to shorten the rod. My head cc was already set in stone as was deck height, well aluminum anyway.
For the debate overall, I will say that in a recent engine building competition, the builders used short rods. The basic rules were, max cubes of 409 and had to run on pump gas. In order to run the max timing w/out detenation, a short rod was used to minimize piston time at tdc. A few of the motors were over 13:1 on pump gas.
Probably not practicle for street motors to run that close to the ragged edge, but nonetheless, there seemed to be some performance that could be found with the 5.7 rod, indirectly so.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
I believe this is just another example of what I call the "bigger is better syndrome".
I've found that many feel if a little is good, more is better. So if a 5.7" length rod is good a 6.0" rod has 'just got' to be better.
But what do I know!? LOL
Jake
I've found that many feel if a little is good, more is better. So if a 5.7" length rod is good a 6.0" rod has 'just got' to be better.
But what do I know!? LOL
Jake
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by JAKE
I believe this is just another example of what I call the "bigger is better syndrome".
I've found that many feel if a little is good, more is better. So if a 5.7" length rod is good a 6.0" rod has 'just got' to be better.
But what do I know!? LOL
Jake
I've found that many feel if a little is good, more is better. So if a 5.7" length rod is good a 6.0" rod has 'just got' to be better.
But what do I know!? LOL
Jake
"If some's good, more's better, and too much is just enough."
RACE ON!!!
