Porting intake manifolds, is it a waste of time? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- 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
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 01-05-2005, 08:34 PM
Mad Maggot's Avatar
The lean mean donut machine
 
Last photo:
Join Date: Aug 2004
Location: Red Deer, Alberta, Canada
Age: 30
Posts: 386
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Porting intake manifolds, is it a waste of time?

I'm pondering whether or not to do some minor porting to my Edelbrock RPM Air Gap intake manifold in search of more upper RPM power. Is this worth the time in terms of power gains or is it just a waste of effort that will do nothing but make the manifold look better from the inside?
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 01-05-2005, 08:48 PM
TurboS10's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Auto Terms and Definitions Used in Modern Engine T... Last photo:
Join Date: Sep 2002
Location: Texas
Age: 36
Posts: 3,463
Wiki Edits: 2

Thanks: 0
Thanked 0 Times in 0 Posts
It certainly cant hurt to port match it to your heads. I dont remember from other threads what you have, but my Dart 230's were alot larger than my ports on my Victor Jr. intake. Plus being the EFI version I had big injector bosses sticking down. I decide it would be worth the few hours to port match and grind down the injector bosses. Like I say it cant hurt.

I found that a 1/2 inch drill and a HSS cutter worked very well on the aluminum. The slower speed seems to keep the cutter cleaner than trying to use a die grinder.

Chris
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 01-05-2005, 08:53 PM
Mad Maggot's Avatar
The lean mean donut machine
 
Last photo:
Join Date: Aug 2004
Location: Red Deer, Alberta, Canada
Age: 30
Posts: 386
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I took advice from an earlier thread on grinding aluminum and ordered a die grinder bit from Goodson. Man that thing chews fast and never clogs up either.

Just wondering, in addition to port matching the intake gasket area, is any work on the plenum going to help?
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 01-05-2005, 09:12 PM
TurboS10's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Auto Terms and Definitions Used in Modern Engine T... Last photo:
Join Date: Sep 2002
Location: Texas
Age: 36
Posts: 3,463
Wiki Edits: 2

Thanks: 0
Thanked 0 Times in 0 Posts
I would leave it be, but that is just me.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 01-05-2005, 09:13 PM
Mad Maggot's Avatar
The lean mean donut machine
 
Last photo:
Join Date: Aug 2004
Location: Red Deer, Alberta, Canada
Age: 30
Posts: 386
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Okalie Dokalie, guess I will just port match and that's it. Thanks for the info.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 01-05-2005, 09:20 PM
tornado-tech's Avatar
Member
 
Last photo:
Join Date: Aug 2004
Location: Kansas
Age: 46
Posts: 320
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Port matching the intake side of the manifold will definitely help upper rpm hp. If the intake is bigger than the head intake port, it will cause puddling though. If the intake is smaller than the head intake port, it will increase velocity of the a/f mixture. As far as the plenum, I'd leave it alone. If you get it too smooth, it will hurt atomization of the a/f mixture.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 01-05-2005, 11:01 PM
troy-curt's Avatar
Shop Owner And Troll Hunter
 

Last journal entry: Detailing Eng. Compartment
Last photo:
Join Date: Apr 2003
Location: Prairie Grove Ar.
Age: 75
Posts: 2,646
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
If it is a divided plenum, you can remove some of the top center and it will improve the upper rpm range. If it is an open plenum leave it alone.

Troy
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 01-05-2005, 11:18 PM
willys36@aol.com's Avatar
Hotrodders.com Moderator
 
Last wiki edit: How to rebuild a Rochester Quadrajet 4MV carbureto...
Last journal entry: How to change auto shift timing on 200R4
Last photo:
Join Date: May 2002
Location: Bakersfield
Posts: 8,372
Wiki Edits: 21

Thanks: 1
Thanked 3 Times in 3 Posts
It's best to buy the manifold that best matches the size of your runners. That way the whole manifold will be sized properly. Then as recommended above, do the port matching routine. And high speed grinders work great w/ carbide bits on aluminum if you use grinder's grease that totally prevents sticky aluminum clogging of the teeth Eastwood sells it. I have a tube that has polished three tranny cases, several intake manifolds, etc., etc., and still has many projects left. Probably a lifetime supply for a hobbyist.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 01-05-2005, 11:45 PM
Big Blocks Rock's Avatar
New Member
 
Last photo:
Join Date: Jan 2005
Location: In my own world
Age: 33
Posts: 15
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I have an add on question. I plan on working a Dodge 383 with MPI for the future, I'm planning on welding bungs onto a Edlebrock single plane manifold and matching it to a set of Edlebrock heads. I want to see if I can port the heads myself and I will match the heads and intake to the gasket. Question is, would I get any performance out of porting and polishing the single plane? I would think that it would. Most of the plenum will just be air, so I wont need the vaporization effect in that area. Oh almost forgot, I am looking at turbocharging it also. I feel that the smooth surface should help in the plenum, especially for the fact that it will be a positive charge. Any comments?
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 01-06-2005, 01:48 AM
bracketeer's Avatar
489 Lemans
 

Last journal entry: Street Legal
Last photo:
Join Date: Dec 2004
Location: Courtenay, BC, CehNehDeh
Age: 54
Posts: 2,139
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
two things

you can gasket match the heads and intake. or you can have them flowed together. but grinding away at them defeats edelbrock's expertise.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 01-06-2005, 06:39 AM
TurboS10's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Auto Terms and Definitions Used in Modern Engine T... Last photo:
Join Date: Sep 2002
Location: Texas
Age: 36
Posts: 3,463
Wiki Edits: 2

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally posted by Big Blocks Rock
I have an add on question. I plan on working a Dodge 383 with MPI for the future, I'm planning on welding bungs onto a Edlebrock single plane manifold and matching it to a set of Edlebrock heads. I want to see if I can port the heads myself and I will match the heads and intake to the gasket. Question is, would I get any performance out of porting and polishing the single plane? I would think that it would. Most of the plenum will just be air, so I wont need the vaporization effect in that area. Oh almost forgot, I am looking at turbocharging it also. I feel that the smooth surface should help in the plenum, especially for the fact that it will be a positive charge. Any comments?
I dont think there is any more need to polish the intake on a turbo application. However, I have read that a perfect turbo intake would have only an open plenium all the way to the valves rather than split ports. Personnally, I am not going to be the first person to try that

Chris
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 01-06-2005, 07:40 AM
willys36@aol.com's Avatar
Hotrodders.com Moderator
 
Last wiki edit: How to rebuild a Rochester Quadrajet 4MV carbureto...
Last journal entry: How to change auto shift timing on 200R4
Last photo:
Join Date: May 2002
Location: Bakersfield
Posts: 8,372
Wiki Edits: 21

Thanks: 1
Thanked 3 Times in 3 Posts
Quote:
Originally posted by Big Blocks Rock
I have an add on question. I plan on working a Dodge 383 with MPI for the future, I'm planning on welding bungs onto a Edlebrock single plane manifold and matching it to a set of Edlebrock heads. I want to see if I can port the heads myself and I will match the heads and intake to the gasket. Question is, would I get any performance out of porting and polishing the single plane? I would think that it would. Most of the plenum will just be air, so I wont need the vaporization effect in that area. Oh almost forgot, I am looking at turbocharging it also. I feel that the smooth surface should help in the plenum, especially for the fact that it will be a positive charge. Any comments?
I don't understand your statement "Most of the plenum will just be air, . . . .". Hopefully the plenum will be filled with a perfect mix of air/gasoline so the vaporization requirement will be the same as any other manifold. Smooth isn't necessarily desirable in intake manifolds. The turbulence caused by rough surfaces is useful in mixing and vaporizing the air/fuel mixture. If your car is a race car running @ 3000rpm and up, by all means get the single plane. However, if you want to do any amount of street driving, stick with the perfomace dual plane design.

On this subject, does anyone know if someone is still offering the 'extrusion' process where they force a paste loaded with carbide grit through a manifold, thus opening up the passages? It was hyped in the rod magazines for a time in the 90s and I have heard zero about it since.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 01-06-2005, 10:10 AM
Max Keith's Avatar
Member
 
Last photo:
Join Date: Jul 2003
Location: Fort Madison,Iowa
Age: 66
Posts: 2,391
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
polishing intakes

I highly advise against polishing intake runners both in the intake and the head. The problem with polishing them is that it allows the fuel air mixture to become unsuspended, costing a lot of HP. What you want is a florentine finish. Something to do with laminar air flow, and since Im not an aeronautical engineer, I wont try to explain it. What I do understand is that you need a certain amount of roughness in the surface of the runners and ports to keep the fuel air mixture suspended.

Polishing on the exhaust port side, however, is an excellent idea.
besides not needing the rough surface to keep the fuel air mix together, polishing the exhaust side reduces the ability of carbon etc to cling to the runners causing restriction.

I heard a lot of hype about extrusion several years ago, but the cost was so prohibitive, compared to any benefits. I think it kind of died on the vine.

You dont want to just go in and start cutting down the divider in a dual plane, indiscriminately.
There is an outfit in Wisconsin called Brezinski that specializes in doing this with factory steel intakes for stock car racing, where stock intake manifolds are required. They also do a lot of other internal work in the intakes.
Ive talked to them a few times. It takes a lot of time and work to get that just right.
Take too much and you mess up a manifold, take too little and youve done nothing.

Plenum chambers are a very finnicky area to play around in.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 01-06-2005, 10:42 AM
troy-curt's Avatar
Shop Owner And Troll Hunter
 

Last journal entry: Detailing Eng. Compartment
Last photo:
Join Date: Apr 2003
Location: Prairie Grove Ar.
Age: 75
Posts: 2,646
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Right, it's not for the novice. I've see a lot of butchered intakes at swap meets. The norm for the street on a duel plane is one inch deep and two inches long in the center of the divider. other than that it would take a lot of flow testing.

Troy
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 01-06-2005, 11:19 AM
Big Blocks Rock's Avatar
New Member
 
Last photo:
Join Date: Jan 2005
Location: In my own world
Age: 33
Posts: 15
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Thank you all for the extra advice.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

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:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

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



All times are GMT -6. The time now is 04:36 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.