Intake plenum turtles - 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
  #1 (permalink)  
Old 06-05-2010, 11:40 AM
vortmax's Avatar
Last photo:
Join Date: Feb 2005
Location: Houghton, MI
Age: 35
Posts: 32
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Intake plenum turtles

I'm planning some intake work on my 3.9L magnum engine. Since there are no aftermarket options, I'm planning on modifying the stock manifold. The manifold is the beer keg style, which has a large plenum volume and a big flat bottom. It's fairly common for people to shorten the runners, clean up the casting marks and unshroud the injector bungs to pick up a few horsepower and move the powerband higher, but I recently talked with someone who built and installed a turtle to fill the plenum volume and help direct airflow towards the ports. He reported a good increase in low end torque.

His design is basically a long, tall triangle that splits the middle of the plenum, peaking 1" from the top with 1/2" space at the edges. I can post pictures later. I'm trying to figure out if the design can be optimized (different size triangle) or if an aftermarket turtle could be adapted and do a better job.

So all of you intake guru's, any rules of thumb about how to go about figuring this out? It might be easier once I get some pictures up of the manifold and the other turtle.

Reply With Quote Quick reply to this message
Sponsored Links
  #2 (permalink)  
Old 06-05-2010, 07:01 PM
techinspector1's Avatar
Last wiki edit: DynoSim combinations Last photo:
Join Date: Oct 2005
Location: Zephyrhills, Florida, USA
Age: 75
Posts: 15,461
Wiki Edits: 326

Thanks: 1,548
Thanked 2,080 Times in 1,609 Posts
In all my 50 years of reading and experimenting, I have never seen or heard anything about what laws of physics pertain to turtles. It is of interest to me though, just as anything automotive is of interest. I suspect that you are all alone in this endeavor though, except for the individual(s) you have identified.

Making different configurations and trying them might be facilitated by the use of a G-meter (accelerometer). Here's a link to an inexpensive home-made unit....

By the way, had some good friends named Zemke here in Arizona in the mid-70's. They were retired here from Houghton Lake, Michigan.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-05-2010, 08:09 PM
vortmax's Avatar
Last photo:
Join Date: Feb 2005
Location: Houghton, MI
Age: 35
Posts: 32
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Yea, manifold design does seem like a black art. I have a background in physics, and have researched it a little, and I still consider it over my head.

I guess at this point I'm looking for more wisdom than knowledge; even non-specific advice from those that have been there, done that, or someone to glance at the picture and recognize the manifold as being similar in design to a different one that maybe has an after market turtle available.

I'm actually up in Houghton (waaaay up in the UP), which is a few hours north of Houghton Lake, but you are by no means the first person to miss that distinction.
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
Oil consumption due to possible sucking oil from intake valley..signs ? y2k600f4 Engine 10 07-31-2010 04:40 AM
Edelbrock Performer vs. Stock Intake crussell85 Engine 8 04-03-2010 08:34 AM
Right cam for a 383? atomicrockerdude Engine 22 11-02-2009 12:13 AM
Intake alignment on SBC raised runner heads y2k600f4 Engine 3 09-18-2009 07:05 PM
Custom intake tube info (Cavalier, but good info for all) TheVis Engine 11 02-09-2007 04:44 AM

All times are GMT -6. The time now is 06:57 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.