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Header building formula? #2815474
08/31/20 11:28 AM
08/31/20 11:28 AM
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MN
J
JERICOGTX Offline OP
master
JERICOGTX  Offline OP
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J

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MN
Is there an online program for figuring out the proper header size for an engine? Tried finding one, but not having any luck.

Thanks.


69 GTX 68 Road Runner
Re: Header building formula? [Re: JERICOGTX] #2815479
08/31/20 11:36 AM
08/31/20 11:36 AM
Joined: Jan 2003
Posts: 11,910
Marion, South Carolina [><]
an8sec70cuda Offline
I Live Here
an8sec70cuda  Offline
I Live Here

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Marion, South Carolina [><]
I seem to recall a bunch of people here using Pipemax.


CHIP
'70 hemicuda...8 sec street car
'69 road runner 440 w/ Indy SRs
'69 road runner 440-6, 4 speed...Dad's ride
'71 Demon 340 resto project
'06 GMC 2500HD LBZ Duramax...toy hauler
'16 Grand Caravan SXT...baby hauler
Re: Header building formula? [Re: an8sec70cuda] #2815498
08/31/20 12:03 PM
08/31/20 12:03 PM
Joined: Jan 2003
Posts: 8,735
MN
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JERICOGTX Offline OP
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JERICOGTX  Offline OP
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J

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MN
Originally Posted by an8sec70cuda
I seem to recall a bunch of people here using Pipemax.


For $150, I'll just SWAG it... Ouch.


69 GTX 68 Road Runner
Re: Header building formula? [Re: JERICOGTX] #2815499
08/31/20 12:05 PM
08/31/20 12:05 PM
Joined: Jan 2003
Posts: 17,679
Las Vegas
Al_Alguire Offline
I Live Here
Al_Alguire  Offline
I Live Here

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Posts: 17,679
Las Vegas
Someone here has pipemax, maybe Mr P?

Re: Header building formula? [Re: Al_Alguire] #2815542
08/31/20 01:46 PM
08/31/20 01:46 PM
Joined: Jan 2003
Posts: 2,829
Shelby Twp. Mi
HardcoreB Offline
master
HardcoreB  Offline
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Shelby Twp. Mi
I get one sized for you LMK via FB...I thought Wallace had one?

Re: Header building formula? [Re: JERICOGTX] #2815550
08/31/20 02:04 PM
08/31/20 02:04 PM
Joined: Oct 2007
Posts: 3,621
New York
polyspheric Offline
master
polyspheric  Offline
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Joined: Oct 2007
Posts: 3,621
New York
Primary ID?
Step?
Primary length?
How big is the exhaust valve?


Boffin Emeritus
Re: Header building formula? [Re: polyspheric] #2815722
08/31/20 11:25 PM
08/31/20 11:25 PM
Joined: Jan 2003
Posts: 5,776
Melbourne , Australia
LA360 Offline
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LA360  Offline
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Melbourne , Australia
Email me the details on the engine Jeff, and I will run it through Pipemax for you

la360racing@gmail.com

Cheers


Alan Jones
Re: Header building formula? [Re: LA360] #2815724
09/01/20 12:00 AM
09/01/20 12:00 AM
Joined: Jan 2003
Posts: 6,401
Minnesota
Hemi_Joel Offline
master
Hemi_Joel  Offline
master

Joined: Jan 2003
Posts: 6,401
Minnesota
I have pipemax but I'm not smart enuff to figure out how to open it. Bring a zip drive next time you come over.


[img]http://i.imgur.com/boeexFms.jpg[/img]
31 Plymouth Coupe, 392 Hemi, T56 magnum
RS23J71
RS27J77
RP23J71
RO23J71
WM21J8A
Re: Header building formula? [Re: JERICOGTX] #2815726
09/01/20 12:23 AM
09/01/20 12:23 AM
Joined: Jan 2003
Posts: 27,796
Oregon
A
AndyF Offline
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AndyF  Offline
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Oregon
How good do the headers need to be? If you are trying to grab every last erg of power then you'll need custom headers since none of the factory built headers have a perfect flange. If you are just building a bracket car then factory headers are fine. If you need to custom build headers for fitment reasons then factory style flanges are a decent place to start. If you want to have headers that help the engine make power then the flange and the first few inches of tubing should match the exhaust port exactly. Most off the shelf headers have a large step at the flange which kills velocity at exactly the wrong point. Get that flange correct and you've won a big part of the battle.

If you can have the first few inches of pipe off the head straight then you'll make more power. If you can use large radius bends you'll make more power. One or two step headers will make more power but cost a lot more money and time. I ran 2 inch dyno headers on my race 514 at 900+ hp even though the formula says I could've gone larger. The trick was that they matched the port very well and they were straight off the ports. The TTI headers I have on my Duster make very sharp bends right at the port. Those headers fit in the car but they cost the engine a bunch of power. Of course as Joe Sherman used to say, "I never found any power in the exhaust". Joe had more dyno pulls under his belt than most anyone in the business, header testing rarely finds much power. Power usually just gets lost on the exhaust side.

I've used PipeMax for years. It is a very useful program for a lot of reason other than header design. If you're serious about making power then PipeMax is a good program to have on hand. The cam portion of it is a little odd but the dyno prediction part of it is pretty good. I think it is built on a very solid math model.

Last edited by AndyF; 09/01/20 12:26 AM.
Re: Header building formula? [Re: AndyF] #2815727
09/01/20 12:32 AM
09/01/20 12:32 AM
Joined: Jan 2003
Posts: 27,796
Oregon
A
AndyF Offline
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AndyF  Offline
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Oregon
Burns is a good place to nose around for information: https://burnsstainless.com/blogs/articles-1/welding-exhaust-systems-part-4

Re: Header building formula? [Re: AndyF] #2815755
09/01/20 06:39 AM
09/01/20 06:39 AM
Joined: Jan 2003
Posts: 8,735
MN
J
JERICOGTX Offline OP
master
JERICOGTX  Offline OP
master
J

Joined: Jan 2003
Posts: 8,735
MN
Originally Posted by AndyF
Burns is a good place to nose around for information: https://burnsstainless.com/blogs/articles-1/welding-exhaust-systems-part-4


I read up on that yesterday. Good info. Thanks for the other info Andy. I plan on buying my stuff through www.racemufflers.com They make different 304 Stainless flanges for BB Mopar heads.


69 GTX 68 Road Runner
Re: Header building formula? [Re: JERICOGTX] #2815776
09/01/20 08:07 AM
09/01/20 08:07 AM
Joined: Sep 2008
Posts: 640
Florida
CJD AUTOMOTIVE Offline
mopar
CJD AUTOMOTIVE  Offline
mopar

Joined: Sep 2008
Posts: 640
Florida
Race Mufflers is Stainless Headers out of Minnesota. They have good US stainless tubing, Rath-Gibson, and their own mandrel bending machines. I use a lot of there tubing based on the quality and price. Burns also uses Rath-Gibson. It is more expensive from them, but the bend quality is also better. Not knocking on Stainless Headers, but the the bend legs are not 100% perpendicular to the radius. That is the difference in price between the two.

Burns has an excellent program, and if you purchase tubing or a flange from them, they will run it for you for free. It is a quite an involved questionnaire about your engine, so have flow numbers, cam spec's, engine spec's, vehicle spec's, etc, available.


Craig Scholl
CJD Automotive, LLC
Jacksonville, FL
www.CJDAUTOMOTIVE.com
904-400-1802

"I own a Mopar. I already know it won't be in stock, won't ship tomorrow, and won't fit without modification"
Re: Header building formula? [Re: AndyF] #2815782
09/01/20 08:19 AM
09/01/20 08:19 AM
Joined: Aug 2009
Posts: 1,057
Ohio
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jlatessa Offline
super stock
jlatessa  Offline
super stock
J

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Posts: 1,057
Ohio
Wow, is that ever a good read, thanks for the link Andy.

Joe

Last edited by jlatessa; 09/01/20 08:20 AM.
Re: Header building formula? [Re: JERICOGTX] #2815821
09/01/20 09:38 AM
09/01/20 09:38 AM
Joined: Oct 2007
Posts: 3,621
New York
polyspheric Offline
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polyspheric  Offline
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Posts: 3,621
New York
W/r/t exit angle of primary:
This presumes that the flange surface is actually perpendicular to the port axis, sometimes they're not.
Read Blair on this, the volume, strength, and direction of both pressure waves and actual gas in a V8 exhaust is utter confusion.
Many formulas end with "then make it 6" longer, and shorten by testing".


Boffin Emeritus
Re: Header building formula? [Re: polyspheric] #2815852
09/01/20 11:24 AM
09/01/20 11:24 AM
Joined: Jan 2003
Posts: 27,796
Oregon
A
AndyF Offline
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AndyF  Offline
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Posts: 27,796
Oregon
That is true. The exhaust flange on a Mopar is angled slightly so if you're building custom headers you have to decide if you want the tubes to be perpendicular to the flange or if you want to have the tubes continue the flow. The cheap and easy way to make headers is to make them perpendicular but that might not be the best way on a Mopar. The dyno headers I use have the tubes coming out of the flanges at a slight angle. Those headers really work well but I can't say they are the "most perfect headers ever". I've done my share of header testing and most of the stuff I see kills power but sometimes you'll find something that actually works pretty well. Schoenfeld dyno headers usually make really good power but of course none of them fit in a car. https://www.schoenfeldheaders.com/sprintdyno1.html

Re: Header building formula? [Re: AndyF] #2815894
09/01/20 02:26 PM
09/01/20 02:26 PM
Joined: Nov 2005
Posts: 14,947
85086
moparpollack Offline
Lil Herman
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Lil Herman

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85086
Get ahold of Harold at Furo racing

http://www.furoracing.com/headers.shtml


55 Pick up 56 Plaza 63 D100 step side 67 Coronet, 68 Roadrunner, 69 Super Bee, 69 Coronet 500 convertible, 70 Roadrunner Post, 79 D150 360, and a severe case of Mopar a,d,d
Re: Header building formula? [Re: moparpollack] #2816053
09/01/20 10:16 PM
09/01/20 10:16 PM
Joined: Jan 2003
Posts: 5,776
Melbourne , Australia
LA360 Offline
master
LA360  Offline
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Joined: Jan 2003
Posts: 5,776
Melbourne , Australia
Has anyone found somewhere that custom makes the megaphone for a collector? I remember finding a shop that did, but can't remember what they're called now. It wasn't the usual places like Burns, SPD, Performance Welding etc.


Alan Jones
Re: Header building formula? [Re: LA360] #2816115
09/02/20 07:06 AM
09/02/20 07:06 AM
Joined: Jan 2003
Posts: 2,829
Shelby Twp. Mi
HardcoreB Offline
master
HardcoreB  Offline
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Shelby Twp. Mi
Based on your 'goals' and combo pipemax generated 2 1/4" @34-36" and 4" coll @ 18"

Re: Header building formula? [Re: AndyF] #2816160
09/02/20 09:48 AM
09/02/20 09:48 AM
Joined: Nov 2003
Posts: 1,536
NW Indiana
F
fbs63 Offline
pro stock
fbs63  Offline
pro stock
F

Joined: Nov 2003
Posts: 1,536
NW Indiana
Wallace Racing has a calculator but PipeMax is the best.

Re: Header building formula? [Re: LA360] #2822036
09/17/20 06:53 PM
09/17/20 06:53 PM
Joined: Dec 2011
Posts: 51
Texas
Chief Offline
member
Chief  Offline
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Joined: Dec 2011
Posts: 51
Texas
Originally Posted by LA360
Has anyone found somewhere that custom makes the megaphone for a collector? I remember finding a shop that did, but can't remember what they're called now. It wasn't the usual places like Burns, SPD, Performance Welding etc.


Is this what you are looking for? I've used them several times, good stuff.
Cone Eng

Dave


Dave Covey
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