Brought to you in part by:

.

Shop Eastwood for your Auto Restoration Needs!


  Mustangsandmore Forums
  Ford Racing
  Header design formulas/charts?

Post New Topic  Post A Reply
profile | register | preferences | faq | search

UBBFriend: Email This Page to Someone! next newest topic | next oldest topic
Author Topic:   Header design formulas/charts?
DutchD58
Gearhead

Posts: 110
From: West Milton, OH
Registered: Jul 2000

posted 09-09-2001 11:43 AM     Click Here to See the Profile for DutchD58   Click Here to Email DutchD58     Edit/Delete Message   Reply w/Quote
Years ago (and I do mean years ago.....before wife v1.0) I had a number of formulas and charts that allowed an individual to design a set of headers based on displacement, RPM and exhaust valve size (primary ID/length and collector ID/length), or to determine the effectiveness of "off-the-shelf" headers for a particular application. I also know that there are a number of other factors that can come into play (valve timing, etc) in such an exercise.
Any of you folks have these formulas/charts at your fingertips that you could either post or e-mail my way?

Thanks,
Kevin

IP: Logged

TomP
Gearhead

Posts: 4780
From: Delta BC Canada
Registered: Dec 99

posted 09-11-2001 03:49 AM     Click Here to See the Profile for TomP   Click Here to Email TomP     Edit/Delete Message   Reply w/Quote
I don't believe its as exact a science as some folks would have you think. What you lose in one RPM range you gain back in another most of the time. You don't want tubes too small that restrict the ports, but an error on the too-large side isn't gonna hurt that much.

Looking at relatively unlimited classes where many cars run near-identical engines, such as the 500 cubic inch NHRA ProStock, you can find Tri-Y and 4 tubes designs in sizes from 2 1/8" to 2 3/8" and a wide variety of collector designs and sizes. All are pretty similar in performance.

IP: Logged

Moneymaker
Administrator

Posts: 19686
From: Lyons, IL, USA
Registered: May 99

posted 09-11-2001 12:18 PM     Click Here to See the Profile for Moneymaker   Click Here to Email Moneymaker     Edit/Delete Message   Reply w/Quote
Headers by Ed in Minn. has those formulas on line I believe. Most of the real race header manufacturers use all CAD equipment these days. Step headers make the most power and you really need a computer to determine the correct tube diameters and lengths for serious horsepower.

------------------
Alex Denysenko
Co-Administrator and Moderator
NHRA/IHRA/SRA member
NHRA and IHRA SS/LA National Record Holder '00 & '01
Fleet of FoMoCo products
Moneymaker Bio
US Class Nationals link

IP: Logged

DutchD58
Gearhead

Posts: 110
From: West Milton, OH
Registered: Jul 2000

posted 09-12-2001 05:17 PM     Click Here to See the Profile for DutchD58   Click Here to Email DutchD58     Edit/Delete Message   Reply w/Quote
Thanks guys. My needs and concerns probably aren't that critical compared to what you gentlemen are trying to accomplish during the racing season.
Right now I have a 2V headed Cleveland and want more, so I have been spending a great deal of time lately comparing various small-block stroker packages to 460 big-blocks for my '73 Torino. Cleveland and aluminum headed Windsor based strokers (392-408 cu.inch) look appealig from a size and weight perspective, but then I'm stuck using off the shelf headers with what may be marginal primary tube size (1 5/8"-1 7/8", depending on engine family and heads). Custom headers would be an option, but would add an additional $600-$800 to my budget.
A 460 with aluminum heads, water pump and intake would be do-able, but 1 7/8" tube headers are the only option for my chassis. Just trying to be thorough before I spend a dime.

Thanks,

Kevin

IP: Logged

Clevo377
Gearhead

Posts: 312
From: Blackburn, Victoria, Australia
Registered: Nov 2000

posted 09-13-2001 06:39 AM     Click Here to See the Profile for Clevo377   Click Here to Email Clevo377     Edit/Delete Message   Reply w/Quote
Kevin, I have a formula to determine peak torque RPM of a given pipe size that I got off a website a while ago. It is:
Peak torque rpm = Tube area x (88200)/(CID/8)
So for a 460 with 1 7/8 pipes (internal):
2.76 x (88200)/(460/8)= 4234 RPM

Food for thought
Paul

IP: Logged

F551
Gearhead

Posts: 172
From: Manitoba, Canada
Registered: Nov 2000

posted 09-13-2001 09:34 PM     Click Here to See the Profile for F551   Click Here to Email F551     Edit/Delete Message   Reply w/Quote
Hey Paul - great formula!
When we dynoed our 500 it made 651 ft/lb @ 4250 rpm with 1 7/8" headers.

------------------
Fred
68 Mustang 500CID/Powerglide - "No Tubs"
86 Mustang GT Cobra

IP: Logged

Clevo377
Gearhead

Posts: 312
From: Blackburn, Victoria, Australia
Registered: Nov 2000

posted 09-14-2001 05:57 AM     Click Here to See the Profile for Clevo377   Click Here to Email Clevo377     Edit/Delete Message   Reply w/Quote
Yeh! It seemed to work for me too. I got it from a series of online lectures given by the "Performance Professor". Was a really good site. Unfortunately it was taken over by someone else, and kinda went downhill (in my opinion). It's a paysite now

Paul

IP: Logged

n2oMike
Gearhead

Posts: 1511
From: Spencer, WV
Registered: Jan 2001

posted 09-14-2001 11:17 AM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
As real header builders know... actual construction is full of compromises. There's a LOT of stuff in the way that needs worked around. Too bad our "dream headers" aren't too often destined for "rail" cars, where there is unlimited room!

I'm sure that formula is for the INSIDE diameter of the header tube. Headers are generally sold by their OUTSIDE diameter. The thinner the tube, the larger the ID. Hooker Super Comps are generally pretty thin. You'll want to do some measuring before doing the math.

Good Luck!

------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/motorcitymustang/cmml/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367

IP: Logged

DutchD58
Gearhead

Posts: 110
From: West Milton, OH
Registered: Jul 2000

posted 09-14-2001 01:34 PM     Click Here to See the Profile for DutchD58   Click Here to Email DutchD58     Edit/Delete Message   Reply w/Quote
Thanks Paul, that's a good start for me!

Kevin

IP: Logged

All times are ET (US)

next newest topic | next oldest topic

Administrative Options: Close Topic | Archive/Move | Delete Topic
Post New Topic  Post A Reply
Hop to:

Contact Us | Mustangsandmore Front Page

Copyright 2003, Steve LaRiviere. All Rights Reserved.


Ultimate Bulletin Board 5.47d

Amazon Honor System Click Here to Pay Learn More

[Build a free Mustangsandmore.ws Home Page!]

[About M&M][Acronyms][Calendar][Chat][Classifieds] [Links] [Members' Pics] [M&M Mug Shots] [Tech] [ Mustangsandmore.com Bookstore] [Advertise on Mustangsandmore.com] [Mustangsandmore.com T-Shirts]