Rod ratio - Page 2 - Hot Rod Forum : Hotrodders Bulletin Board -- Hot Rod Forum

Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
lost password?   |   register now

LinkBack Thread Tools
  #16 (permalink)  
Old 11-29-2005, 06:27 PM
smallblocker2's Avatar
L79 327 5SPD S10 '65GTO
Last photo:
Join Date: Apr 2005
Location: Langley B.C.
Age: 38
Posts: 250
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Induction signal that's too strong! Never heard that one before.

many of you have said that this debate will never be solved, that there are no true facts. I could go on to quote famous tuners, or something from the 100's of pages of literature I've read on the subject, But the general concensus seems to be that the longer rods make more power. Though small and not worth the effort, in most's opinion's. But more still.

Let's ask this question. If you could get a quarter inch longer rod, at the same price, pistons and all, would you? or not?

sorry if I sounded like a ***** saying it like that.


Last edited by smallblocker2; 11-29-2005 at 06:35 PM.
Reply With Quote Quick reply to this message
Sponsored Links
  #17 (permalink)  
Old 11-29-2005, 06:52 PM
Last photo:
Join Date: Sep 2002
Location: New Jersey
Posts: 416
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Thats exactly why I have a 1/4" longer rod in my 427,but again it depends on the application.If it meant running a narrow ring package in a street engine instead of a wider more durable package I would say no.If it meant putting the top ring less then .100" from the top of the piston on just about any engine I would say no.If it meant not being able to get an extra half inch of stroke in the engine I would say no.If it meant going over about 1.85:1 on the rod ratio I would say no unless it was some oddball exmaple of some super short stroke engine that would need 1000 gram pistons just to make it go together,and even then I would be skeptical.

As for induction signals,increasing the speed at which the piston moves away from TDC on the intake stroke causes the demand on the intake to be greater at this part of the cycle,while being weaker at the end of the intake cycle.This isnt good since this requires that the valvetrain be timed to get as much lift at the valve as possible at or around the time the piston crosses TDC to take advantage of the high piston speed,and it means that the slow approach to BDC will somewhat deminish to velocity in the port as the piston crosses BDC and will require an earlier intake closing event which limits RPM potential.This problem was a big issue when Comp eliminator drag engines had to run standard deck height blocks.These engines had a surplus of cylinder head and intake flow,but poor velocity because the ports were typically larger then optimum for these super destroked engines,The problem was made worse by the fact that the only was to get a sane piston weight out of a 3" stroke smallblock with a 9.2" deck height was to run 6" rods which created the induction pulse problems I mentioned above.The problem was further aggitaged be the fact that in order to get more signal up to the carb through the already too big indiuction system,builders took plenum volume out of the intakes which helped low speed signal to the carbs but caused reversion at high speeds.

Think of it like this,a 3" stroke or even 2.75" stroke Comp smallblock could easily run a 6.25" rod in a stock height block with no issues,and a 3.650" stroke 500 cube prostocker could easily run 6.800" rods in a stock height block with no compromise to piston design,but for the same reason
both classes use very expensive and very trick "low deck" blocks that let them use much shorter rods with these combinations.

3 hp per cube normally asperated on gas isnt something to scoff at the last time I checked.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Please select your insurance company (Optional)


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
tot rod mike c Hotrodders' Lounge 2 05-02-2007 12:40 PM
max compression ratio on 89 octane gemini86 Engine 31 07-01-2005 03:35 PM
detonation resistance, short or long rods? Old School Nut Engine 34 12-31-2004 12:23 AM
Transmission Information. M&M CUSTOM Transmission - Rearend 1 08-24-2004 03:15 PM
Q-Jet Metering Rod Idea Silver_Camaro Engine 6 09-16-2003 01:48 PM

All times are GMT -6. The time now is 04:54 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999 - 2012. All Rights Reserved.