building custom headers



building custom headers

Postby grumpyvette » December 22nd, 2008, 6:33 pm

theres a great deal of useful info in these links , and sub linked info so don,t skip over them without looking thru carefully, as theres years of experience to be gained

at times you need to do some minor fabrication to get things to fit & function, so having a welder and knowing where to get header flanges helps, but some careful measuring will yield surprising results at times, like BIG BLOCK CHEVY HEADERS CAN BE MODIFIED TO FIT A 500 CADDY ENGINE
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you might want to install a 496 big block chevy in a 1969 AMX, and a DANA 60 rear differential, that will require a bunch of carefully measured custom fabricated custom components, something any true hot rodder can do with the correct tools like a decent welder and access to a mill,but you won,t find the parts required in any catalog.
if you have ever done the math required to calculate the ideal header dimensions for a serious big block engine youll find most headers would require longer header primary tube lengths, closer to the 36"-39" length and using the 3.5"-4" collectors at least 18"-22" long that are rather easily built with the side exhaust design but almost always too restrictive to fit for clearance issues with an under the car exhaust.
or put a different way, the basic lay-out of a properly designed side exhaust lends itself more easily to a max effort exhaust,provided you junk or replace the highly restrictive inserts and replace them with some other option
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http://forum.grumpysperformance.com/viewtopic.php?f=56&t=2350


http://forum.grumpysperformance.com/viewtopic.php?f=80&t=793&p=30576&hilit=+side+pipes#p30576

http://forum.grumpysperformance.com/viewtopic.php?f=56&t=9296&p=33590#p33590

http://forum.grumpysperformance.com/viewtopic.php?f=56&t=7831&p=26979&hilit=+side+pipes#p26979

http://forum.grumpysperformance.com/viewtopic.php?f=56&t=495

http://forum.grumpysperformance.com/viewtopic.php?f=56&t=185

http://forum.grumpysperformance.com/viewtopic.php?f=56&t=1166
http://www.coneeng.com/collector_components.html

http://icengineworks.com/Catalog2012Ed2 ... sionLR.pdf

http://www.wallaceracing.com/header_length.php

http://www.wallaceracing.com/header_length.php

http://www.jefflilly.com/fabrication/he ... brication/

http://maxracesoftware.com/pipemax36xp2.htm

viewtopic.php?f=56&t=1303&p=16831#p16831

http://www.icengineworks.com/icewmain.htm

http://www.hotrod.com/techarticles/hrdp ... ipe_dream/

http://www.hotrod.com/techarticles/hrdp ... ipe_dream/

http://www.stainlessheaders.com/headerfabrication

http://www.metalgeek.com/static/cope.pcgi

http://www.superchevy.com/technical/eng ... index.html

http://www.bgsoflex.com/bestheader.html

http://www.carcraft.com/techarticles/he ... usion.html

http://www.centuryperformance.com/exhau ... g-137.html

http://www.mandrel-bends.com/catalog/ma ... -gauge-74/

viewtopic.php?f=56&t=185

http://www.carcraft.com/howto/ccrp_0803 ... _list.html

http://www.spectrum5racing.com/Technica ... erRevA.pdf

http://victorylibrary.com/mopar/header-tech-c.htm

http://www.pontiacracing.net/js_header_length1.htm

http://www.mk5cortinaestate.co.uk/calculator5.php

http://www.carcraft.com/howto/ccrp_0803 ... index.html

http://www.carcraft.com/howto/0304_head/index.html

http://www.centuryperformance.com/exhau ... g-137.html

http://stockcarracing.automotive.com/49 ... sions.html

http://www.carcraft.com/techarticles/11 ... ndex2.html

http://www.stainlessworks.net/cart/pressrelease.php

http://www.jefflilly.com/Fabrication/Fa ... t/page.htm

viewtopic.php?f=56&t=352

http://victorylibrary.com/mopar/header-tech-c.htm

http://store.racing-solutions.org/

http://store.summitracing.com/largeimag ... OK-2956HKR

http://www.burnsstainless.com/MergeColl ... ctors.html

http://www.stahlheaders.com/Frame%20Flanges.htm

http://www.stansheaders.com/gm_flanges.htm
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IF your are unfamiliar with SMURF TUBE ITS USED FOR ELECTRICAL CONDUIT
now obviously the exhaust lego kit the links point too, is a better route but I never knew they existed until recently and their kit of fabrication parts, is very expensive..
Ive done this many times its not that hard. here is what I do, get some of that plastic smurf tubing in the 2" diam. size and some ceiling hanger wire and some of that hard set construction insulation foam. now weld 1" stubs of the exhaust tube to the header flange exhaust ports and bolt it to the cylinder heads. clamp the collectors to a 6 foot section of 2x6" wood and jack it up solid under the car (collectors not touching the car anywhere)to position them where you want them under the car, now cut (8) sections of smurf tubing too about 36"-42" long(theres a formula to figure the exact length)slide 4-6 pieces of ceiling suspension wire in each tube with the ends looped over inside the tube. now starting with the upper inside collector position and the rear exhaust port, bend and fit the smurf tubing to fit, the next forward exhaust port goes to the lower inside collector port the next exhaust to the upper outside collector port and the furthest forward to the lower outside collector port , once they are all bent to fit shoot the tubes full of hardening construction foam, let it harden and then pull each individual tube off one at a time and duplicate it in steel tubing, by cutting and welding sections and dozens of trial fits before you permanently weld ANYTHING!(or have your local muffler shop duplicate it,.. MOST WON,T AS ITS VERY LABOR INTENSIVE) this method REALLY makes the fit and try time minimal.(YES ITS STILL A ROYAL P.I.T.A.) and assures equal length tube headers.SMURF TUBE is flexible plastic electrical conduit that's normally BLUE or ORANGE and COMMONLY called smurf tubing by contractors its a plastic version of that metal GREENFIELD tubing that electrical contractors use but its cheaper and easier to work with, it resembles a canister type vacuum cleaner pickup hose but stiffer, its available at big hardware stores,and electrical supply houses dirt cheap in 10' lengths about $6 each or less you will need (3)BTW the 4-6 wires act like re-bar in concrete, the loops keep the wires from moving in the foam while their encased in the construction foam, the hard plastic foam is what keeps it stiff and no it will not be exact you will still need to tweak it to get it to fit but it will speed up the process of making the tube pattern shapes. just keep in mind that you can buy headers fairly cheaply (under $300 in many cases) for most cars its when you go and get an odd ball combo this comes in handy, like putting a 502bbc in a 57 vette or a 392 hemi in a 63 falcon.
IN MANY CASES A SIMILAR CARS HEADER CAN BE USED AND ONLY ONE OR TWO PRIMAIRY TUBES NEED RE-ROUTING

example , my 383 vette has a cam with exhaust cam timing that opens at 83degs bbdc, thats 97 degs atdc, http://dab7.cranecams.com/SpecCard/D...1=Display+Card
Bore: (Inches) 4.03"<BR>Exhaust Valve Opening Point: (Degrees ATDC) 97 degs
Peak Power RPM: 5500rpm Calculated information appears below
Header Pipe Diameter: (Inches) 1.84"<
Header Pipe Length: (Inches) 37.65
Collector Diameter: (Inches) 3.5
Collector Length: (Inches) 18.82
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: building custom headers

Postby grumpyvette » December 30th, 2008, 9:13 am

as a tool junkie.....damn this looks nice (would be nice to be filthy rich....would it not!)so you could afford to put 3" stainless exhaust like this on all your cars
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A CORRECTLY TUNED SET OF HEADERS , MATCHED TO A CORRECTLY DESIGNED CAM TIMING HAS A SIGNIFICANT EFFECT ON INTAKE FLOW AND CYLINDER SCAVENGING EFFICIENCY
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HAVING DUAL X PIPES MIGHT SEEM REDUNDANT BUT ITS PROVEN TO INCREASE CYLINDER SCAVENGING, NO HEADER CAN FUNCTION WELL IF ITS GOT BACK PRESSURE, RESTRICTING EXHAUST FLOW
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HEADERS LIKE THIS SET PICTURED ABOVE< ARE VERY POORLY DESIGNED, AND ALMOST WORTHLESS, AS THEY WILL DESTROY THE SPARK PLUG WIRES WITH HEAT RAPIDLY

THE MOST COMMON SCREW-UP Ii SEE IS GUYS HAVING IGNITION WIRE THAT GETS MELTED ON HEADERS, ITS THE HEADER DESIGN MORE THAN ALMOST ANY OTHER FACTOR THAT CAUSES THIS, SO BEFORE BUYING or FABRICATING CUSTOM HEADERS TRY TO FIND A SIMILAR SET THATS BEEN INSTALLED AND CHECK THE PLUG & WIRE CLEARANCE/ACCESS, OR THINK THRU EASY ACCESS DURING THE FABRICATION, doing that, so you can avoid badly designed headers, can save you years of grief, obviously the picture above shows badly designed headers and the picture below much better plug access
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http://www.amazon.com/Jet-414459-HVBS-7MW-Horsepower-Horizontal/dp/B00004T9KT/ref=pd_cp_hi_1?pf_rd_p=413863601&pf_rd_s=center-41&pf_rd_t=201&pf_rd_i=B00004T9KU&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=10SC7YMAV2V2GDZSN2M4

http://vansantent.com/tube_bending_mach ... chines.htm

http://www.asedeals.com/tubing_benders.html

http://www.stainlessheaders.com/headerfabrication

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If you can,t find a decent quality header there are ways you can build a custom set-up, just a suggestion.........build a custom set exactly to the correct length for your application, with the correct collector.
obviously youll want to do a few basic calculations and realistically assess your intended power and rpm range
but don,t get crazy, a good set of full length commercial headers may give you 70%-90% of what a custom header that costs three times as much will give you, especially if your using an exhaust system and its restriction to flow behind the collectors

you start by clamping the collectors where you want them after measuring to allow room for the correct primary tube length, and bolting the header flanges to the heads with the engine in the car, read thru the inks for ideas

theres readily available calculator info in the links posted below so take the time to read thru the linked info and sub links as it can save you days of work and a bunch of cash
theres pre-cut header flanges

http://www.summitracing.com/parts/HOK-11622HKR/
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theres pre-welded collectors, its really not all that difficult

http://www.summitracing.com/parts/FLO-C134218234/

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http://www.summitracing.com/parts/DTC-80-01514C/
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IT would be hard to significantly improve on this basic lay out
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LINKS YOU'LL WANT TO READ

http://www.carcraft.com/techarticles/11 ... ndex2.html

viewtopic.php?f=56&t=185

http://www.stansheaders.com/gm_flanges.htm

http://www.piletips.com/Weld_Chill_Rings.htm

viewtopic.php?f=56&t=352

viewtopic.php?f=56&t=789

viewtopic.php?f=56&t=496

viewtopic.php?f=56&t=2870


knowing a few constants in engine pressure and flow helps


an engine usually requires approximately 2.257 cubic feet per minute per horsepower to maximise intake flow and exhaust flow at about 115 cfm per square inch

so assuming your building a 500 hp engine / 2 (divided by 2 as there's normally two header collectors on a v8) we have 250hp per header collector, (open header collectors) multiply that by 2.257 cfm and you see you need 565 cfm and divide that by 115/square inches and we see we need a 4.9 square inch minimum exhaust collector pipe, per side (open header collectors).

as a cross check 500hp /8=1129/8=142 hp per header primary , 2.257 x 142/115=2.76 sq inches 0r a header primary a bit larger than 1 3/4 and smaller than 2" or a 1 7/8 to maximize peak hp, per header primary, but keep in mind you'll spend most of your time below peak rpms so a slightly smaller 1 3/4" primary on a street strip engine that sacrifices a bit of peak hp for better mid rpm torque makes sense, and once you install longer exhaust pipes and mufflers you'll need to step up the exhaust pipe size cross section past the header collectors or they will tend to be restrictive at the minimum size the formula predicts
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viewtopic.php?f=60&t=1958

viewtopic.php?f=60&t=72


I got asked if swapping to custom header collectors was worth the effort and if 4-2-1 collectors worked?

Ive done it easily a dozen or more times and its never HURT, a few times it failed to produce noticeable gains but most of the times it improved low and mid rpm torque and broadened the torque curve, many factory headers are too short to provide ideal power curves, obviously do the math and measure first, because getting it correct helps, getting it wrong just costs money and takes time and probably ruins your current headers, BTW a TIG welder and BACKING the weld with shield gas helps.
keep in mind its not likely to be a huge improvement, your likely to gain 20-30 ft lbs in low rpm torque and 5-7 hp in the mid rpms, but peak hp might even fall 3-4 hp, but your average torque generally improves and picking up a 0.10 in the 1/4 mile is not UN-common in my experience, and don,t make the common mistake of cutting off the old collector and welding on the new extended collectors without carefully checking angles and clearances under the car, its amazing the number of guys that never think about clearance and routing issues until after they weld on extended collectors

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heres a few pictures of 4-2-1 collectors off the internet
summit sells these
you ideally want to have a 4-2-1 config to maximize the engines power potential with the exhaust primairy tube size just a bit larger that the heads exhaust port size, with each step up in diam, in a 4-2-1 config header where two smaller tubes join a larger remain as small as practical while still allowing the twin feed pipes to fit into the larger pipe they feed into,thus the internal area of a 1.625" primary pipe, (as an example ) is about 2.01 sq inches, so at least in theory a 2.25 inch diam could be swaged to fit and allow the twin 1.625' primary to feed, but in reality the 2.5" is going to be more practical taking the tubing wall thickness into account, Id then feed both those into a single pipe of the smallest practical size that will physically fit

http://www.summitracing.com/parts/FLO-C134218234/
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I generally just buy the set of these and weld them on,to the primaries cut to 36"-38" as it saves a great deal of work and the results have proven to be similar, ideally the two collectors feed into an (X) pipe with fairly long tail pipes as this seems to help the torque curve be a bit broader , even if it does cost a few peak ft lbs
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CORSA came out with a more efficient DUAL (X) PIPE exhaust and headers for the c7 corvettes, the increased scavenging effect of dual (X) pipes is something I've promoted for decades
MY c4 vettes exhaust looks similar to this
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Ive always been amazed at the number of guys who think the only options they have in components , they can use on a car, involve buying and installing parts listed in a catalog.
adding a dual (X) to the exhaust system has proven to reduce the decibel level and spread the torque curve on several corvettes, Ive done that mod to the exhaust on,as it tends to increase the cylinder scavenging efficiency,and reduce the exhaust back pressure, and I read that modifying headers in a similar manor is worth .05 seconds on several cars, so don,t think a bit of thinking outside the box as they say won,t pay off in a bit more power or power over a wider rpm band.

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http://www.pfyc.com/pc/C75003/C7EXH/Cor ... ngray.html

http://www.pfyc.com/pc/C75005/C7EXH/Koo ... ngray.html

heres the new corvette dual (x) pipe
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https://www.youtube.com/watch?v=f61NC3It8Jc

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http://www.summitracing.com/parts/FLO-C134218234/

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http://www.burnsstainless.com/2into1.aspx

http://forum.grumpysperformance.com/viewtopic.php?f=56&t=961

http://forum.grumpysperformance.com/viewtopic.php?f=56&t=1303

http://forum.grumpysperformance.com/viewtopic.php?f=56&t=1166&p=8363&hilit=sugar+paste#p8363
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: building custom headers

Postby grumpyvette » October 23rd, 2010, 8:33 pm

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Posts: 14105
Joined: September 14th, 2008, 1:40 pm
Location: florida

Re: building custom headers

Postby grumpyvette » November 28th, 2010, 8:30 am

http://www.popularhotrodding.com/tech/0 ... index.html

theres more info in the article but these bits may help
http://www.spdexhaust.com/

http://www.mandrelbendingsolutions.com/ ... ipe/Detail

PRIMARY PIPE DIAMETER FACTORS
The primary header pipe diameter is determined using basic engine mechanical specifications, such as: Bore Stroke Compression Ratio Valve diameter Cam specifications (lift and duration) Target rpm range
0310Phr Burns 03 A Z

PRIMARY PIPE LENGTH
"The overall length of the primary header pipe is governed almost exclusively by the target engine's rpm range, which is dependent upon wave tuning. Typically, a lower engine rpm range likes a longer primary pipe, while a high rpm engine prefers a shorter primary."

SECONDARY PIPE DIAMETER
While typical off-the-shelf street 4-into-1 headers do not have secondary pipes, Burns' research has proven repeatedly that his Tri-Y designs make more overall power over a broader rpm range. While traditional lines of thought have street enthusiasts knowing Tri-Y pipes make more bottom-end torque, further research by Burns into the design have resulted in headers making more power all across the rpm range. With more components as part of the Tri-Y design, more tuning possibilities exist, and therefore more potential lives within.
0310Phr Burns 04 Z

"The secondary pipe diameter is determined by considering both pressure waves and reflective waves throughout the system. Since the pipes are paired according to the firing order, these waves can work together or against each other. Naturally, our designs work with the waves to increase the efficiency of the header, using the wave pulses to help pull gases from the engine.

"There are two basic kinds of waves we're dealing with. First, there are pressure waves. The pressure wave travels the length of the primary pipe in a 4-into-1 header, then is reflected from the collector where the area changes from the small-diameter primary into the larger-area collector. A reflection of negative pressure goes back up the primary pipe.

"In a Tri-Y design, the pressure of additional area changes (where the primary pipes become secondary pipes) produces additional reflections, so the Tri-Y must be designed in a different manner with respect to wave control. Given this, the area of the Tri-Y header between the first and second collectors becomes critical, and tuneable. The entire header is affected by this crucial length of pipe, and can be fine-tuned accordingly through proper sizing for optimal broad-range performance.

"The 4-into-1 pipe is also affected by altering pipe lengths, of course. But, without these secondary pipes it is impossible to tune with the same level of precision as with the Tri-Y headers. It's for this reason we prefer the Tri-Y design in most applications. The tuneability is so much more accurate, we're able to find more power over a broader rpm range. This is especially critical in engines expected to work well over a wide rpm range, like street machines."

Another huge reason for the move to Tri-Y headers is weight savings. Burn's claims most of their Tri-Y headers weigh in at about _ the weight of comparable 4-into-1 pipes for the same application, due to the smaller pipe diameters used throughout similar applications. Also, with less internal volume than comparable 4-into-1 headers, the Tri-Y equipped engine is typically more responsive. Tri-Y designs require physically smaller collectors as well, contributing further to space and fit concerns, and adding further to crisp engine responsiveness.

COLLECTORS
"There is much power to be found in researching collector design and size. The optimal collector is determined by several variables, and it's engineering interacts with the entire exhaust system. The internal volume, the outlet size diameter, and the angles at which the pipes come together within the collector are all factors that must be maximized for the header to perform to its full potential."

1 - Primary Pipe Entry Size
"Our computer model design program determines many of these hard dimensions based on data gathered over many years, including the length and diameter of the primary or secondary pipe entering the collector."

2- PRIMARY PIPE ENTRY ANGLE
"The pipe entry angle is typically between 10-20 degrees, with most pipes being right at 15 degrees. The cone (or goilet) formed between the pipes as they transition from primary to collector is formed as a consequence of these angles, nothing more. The mass of gases moving through the pipe does not want to change direction, so keeping these "pyramid" cones true to the pipe entry angle helps smooth the transition from the relatively small volume of the feed pipe to the larger volume of the collector."
0310Phr Burns 06 Z

3 - COLLECTOR OUTLET DIAMETER
"The collector outlet diameter is the most critical dimension in the header. It's what makes the merged collector work the way it does. Each collector we sell is custom-sized to each customer's engine, and there's no real 'formula' to get a broad-based general determination for street machines. As a rule, the overwhelming majority of aftermarket headers designed for the street market have way too big of a collector outlet diameter. Most street guys are losing power because of badly designed, manufactured, or engineered street headers. There is much room for improvement here."
0310Phr Burns 05 Z

4 - OVERALL COLLECTOR LENGTH
"Overall collector length is not critical. Once the other variables in the header design have been determined, the collector ends up being as long as it needs to be. We've found no benefit in lengthening or minimizing this dimension. It's more important to properly engineer what's going on inside the merged collector, and let the length determine itself once all the other important factors are optimized."
0310Phr Burns 07 Z

AFT OF THE COLLECTOR
One of the growing areas of research at Burns is the critical area just aft of the all-important collector outlet. Burns' dyno research led him to begin experimenting with interchangeable venturis, which slip into receivers just aft of the collector. While these prototype dyno parts were initially crafted to assist Jack in determining the critical overall collector diameter size, he soon realized they could be a marketable product. His initial "DynoSYS" product for dyno research evolved into a line of interchangeable sleeves called the Burns Tuneable Exhaust Collector, or BTEC for short.
0310Phr Burns 08 Z

The BTEC system has shown capability to alter the entire power curve of the engine. By changing only the insert, racers can change the entire tune on their engines to fine-tune for track conditions, weather, or driver preferences. Mostly used by drag racers, many in Pro Stock, the BTEC system offers enthusiasts a glimpse into the future of header design. While the drag racers have already embraced the benefits of BTEC, a number of road racers are beginning to experiment with the system as well.

Burns is also working with stealthy reverse-cone megaphones, which perform a similar task. While much information regarding the use of his reverse-cone megaphones remains secret, street enthusiasts should understand the use of these products is still primarily confined to open (unmuffled) exhaust systems. Therefore, there is little to be gained at this point in time from digging deeper into the design. In the future, products like this may impact the street market, but at this time they are purely race-only parts.
0310Phr Burns 09 Z

X-PIPES
One area street machine enthusiasts are aware of is the evolution of the X-pipe. Early on, connecting the left and right halves of a true-dual exhaust system with an H-pipe resulted in measurable benefits. This theory evolved into the X-pipe, which allowed both left and right portions of the exhaust system to share some common flow area and resulted in even greater gains in power with a notable reduction in exhaust noise. This win-win situation prompted Burns to research even further, and his X-pipe designs stand among the finest and most-effective in use today.
0310Phr Burns 10 Z
Here's a look at a typical...

read full caption
0310Phr Burns 10 Z
Here's a look at a typical NASCAR Winston Cup header, as designed and manufactured by Burns Stainless. Naturally, construction is all stainless steel, each pipe is researched for optimal performance, and many portions of the pipe are interchangeable for fine-tuning. This is a GM SB2 header; Ford- and Mopar-based headers are quite similar.

"Our X-pipes are designed for maximum inertial flow, and unlike other X-pipe designs, exhaust flowing through our X-pipe sees a minimal direction change. By minimizing the entry and exit angles of the X-pipe, we were able to limit the restriction through the unit, and find more efficiency. Exhaust flow does not like to change direction, so this is only logical.

"Most of our race customers still do not use X-pipes, but interestingly most of the NASCAR Winston Cup teams use them in their restrictor plate cars. For a street enthusiast, they are highly recommended."







WHICH STAINLESS TO USE?

Within the 300 series of stainless steels, there are four types that are suitable, available and cost effective for the racer. These are 304, 316L, 321, and 347.

321 and 347 are known as stabilized grades of stainless. These are alloyed with either titanium (321) or columbium (347), both of which have a much stronger affinity for carbon than does chromium at elevated temperatures. This eliminates carbide precipitation leaving the chromium where it belongs for corrosion protection...remember our discussion of intergranular corrosion? Both 321 and 347 are top choices for exhaust headers, especially turbocharger systems and rotary engines. Since 321 is much more available than 347, that leaves 321 as the first choice, with no sacrifice in needed qualities.

316L is an extra low carbon (ELC) grade of stainless that has only .03% carbon, making less carbon available to precipitate with the chromium. It is used extensively in marine exhausts where salt water corrosion mixed with diesel exhaust particulates and electrolysis create such a horrible environment that even other grades of stainless cower and run away!

304 is the most inexpensive and available stainless in the 300 series. It is suitable for normally-aspirated header applications, and has been successfully used by many racing teams. It does not have the high temperature fatigue resistance that 321 does, but is considerably less costly and much more available. Most 304 tubing these days has the dual designation of 304/304L.

Practically speaking, there are overlapping applications of 304 and 321 stainless in header construction, but knowing you've got the insurance of the aircraft-grade 321 for the job is definitely worth consideration of the extra cost... if your application requires it.

Stainless steels come in both tubing and pipe sizes. Since certain pipe sizes are almost identical in dimension to tubing sizes, pipe may sometimes be substituted for tubing, and vice versa. Numerous wall thicknesses are available, but for headers, normally .049" (18-gauge) to .065" (16-gauge) is used.

Different specifications are used to meet particular requirements for the military (MIL), the American Society of Testing Materials (ASTM), and the Society of Automotive Engineers (SAE). Examples of what to look for when you order stainless tubing are as follows:

ASTM A-554 304 stainless is a welded mechanical tubing used primarily for ornamental purposes. It is not fully annealed and is work-hardened slightly in manufacturing. It has good column strength and good bendability. ASTM A-269 304 stainless is a general service commercial specification that is higher quality and is fully annealed for better ductility. It is available in both welded seam and seamless, and is a good spec for the racer to use. We have not seen any difference in longevity between welded seam and seamless stainless tubing in header use, but there is a substantial cost difference. The column strength is not as good as A-554, but it has excellent bendability with a higher cost due to the full annealing.

MIL-T-8808/8606\MIL-T-6737 321 stainless are military specifications for aircraft tubing. Suffice it to say that some MIL-specs are not necessarily better or even as good as some ASTM standards. There is no particular magic here.

There are as many uses for stainless steel as there are projects in the shop. There is nothing else that transmits an image of quality and skill to the majority of fabricators than a cleanly constructed stainless steel project. Whether it is a set of headers, intake stacks, or even a stand for one's dyno engine cooling fan, stainless steel has such great mechanical properties that its use should be considered for many projects beyond exhaust systems."
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headers with this basic lay out produce both good peak hp numbers and a wide torque band

http://www.carcraft.com/techarticles/he ... usion.html
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: building custom headers

Postby grumpyvette » December 4th, 2010, 3:41 pm


READ THRU THIS

http://www.circletrack.com/enginetech/c ... index.html

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like most things EXPERIENCE HELPS, but if you mock up whats needed its not going to be difficult to do.
generally you carefully measure, the length and angles and buy a few pipes to cut and weld and use a pipe expander
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http://www.spiderautomotive.com/benttubing.html

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to make one end female so you can slip the normal pipe inside a slip fit giving you some leway on exact length.

viewtopic.php?f=56&t=1166

http://victorylibrary.com/mopar/header-tech-c.htm

http://headerdesign.com/

A GREAT DEAL of the results will depend on the exhaust header design,MOST commercial headers are designed with low cost and ease of installation in mind rather than max scavaging and max HP. KEEP IN MIND the main function of headers is to increase the efficincy of the SCAVAGING of the spent gases in the cylinder and help draw in the following next fuel/air charge in the intake runner of that cylinder,thru the use of timing negative pressure cycles,and reversion pulses in the exhaust port, but the exhaust restriction level behind the headers can kill most of the potential results from even the better designs, ANY SIGNIFICANT RESTRICTION TO FLOW AND RESULTING BACK PRESSURE WILL HURT YOUR RESULTS ,if your not willing to change the whole system to optomize the results , and lower the restriction to flow past the collectors on those headers, then a stock or modified stock or shorty headers will be a decent choice, if the FULL LENGHT HEADERS are MATCHED to a full length, 3" exhaust with an (X) that will significantly lower the restriction to flow rates. the stock corvette exhaust manifolds tend to be far better than most stock exhaust manifolds but they still fall far behind what a decent set of full length headers and a low restriction exhaust will do for your cars power.
design the system correctly and you can significantly increase the exhaust scavaging of the cylinders and increase power,do it wrong and youll hurt power.

http://store.racing-solutions.org/

http://www.sjdiscounttools.com/waebpt01.html

readings above about 1.5 psi usually indicate a restriction thats costing you power.

the main IDEA is to REDUCE restriction and EQUALIZE the flow, AND INCREASE the CYLINDER SCAVAGING to help power by increasing the cylinder filling efficiency. side benefit is usually a more mellow exhaust tone
lets say your car has two 2.5" exhaust pipes, blending the flow thru use of an (X) doubles the area and cuts the restriction almost in 1/2, plus if designed correctly it helps scavaging, a single 2.5" pipe cross section is approximately 4.9 SQ" a single 3" has approximately 7 sq inches of cross sectional area, so adding an (X) effectively reduces the restriction almost in half but stepping up the size and adding an (X) beyond the header collectors does far more at reducing the restiction

THE (X) BY FAR is more effective, the (H) may equalize the pressure to a great extent but the (X) blends and exqualizes the flow, READ THRU THE LINKS AND PAY ATTENTION TO THE MATH

http://www.uucmotorwerks.com/html_product/sue462/backpressuretorquemyth.htm

http://victorylibrary.com/mopar/lcb-c.htm

http://victorylibrary.com/mopar/header-tech.htm

http://forum.grumpysperformance.com/viewtopic.php?f=56&t=1730

http://www.pontiacracing.net/js_header_length1.htm

http://www.engr.colostate.edu/~allan/fluids/page7/PipeLength/pipe.html

http://auto.howstuffworks.com/question172.htm

http://www.superchevy.com/technical/engines_drivetrain/exhaust/0504sc_header/index.html

http://www.carcraft.com/techarticles/header_basics/index.html

you can easily meassure this, get a pressure gauge and drill a 1/8" hole in the exhast behind the headers and bring the engine up to full throttle with the gauge attached, (I usually suggest running thru the gears on a semi hard accelleration test run with a partner in the pass seat watching the gauge readings, with a temp test line to the gauge running into the cab thru a window.

whats the differance?
lets say for the example the exhaust pulse is a quart to water moving at several hundred feet per second, but unlike water it can be compressed,since the exhaust pipe inside dia. is set the length of the pulse or slug of exhaust exiting the engine every 90 degrees of rotation (v8) has inertia/energy/mass, if it passes a right angle low pressure exit point, at first it flows into both routes but as the mass passes the opening a slight negetive pressure forms and it reverses and the flow changes, put a vacuume gauge on the (h) and it vibrates, wildly.
install an (X) and the flow from both sources is FORCED to BLEND, line up, equalize and BOTH sections of the up stream flow benefit from the
as each inertia/energy/mass, and slight negative pressure that forms, but its far more equalized. gases unlike liquids will expand to fill any void.
put another way if one side was pumping out dark green water and one side was pumping clear, an (H) would have dark green exiting one side and light green exiting the other, an (X) would have both sides an equal, slightly lighter green flow .now at low rpms , or with a smaller than ideal pipe dia. thats no big deal, but at high rpms, BOTH the SCAVAGING of the cylinders your trying too scavage enhances the effect and the reduction of the restriction to flow tends to be better with the (X) put a vacuume gauge on the (X) and it vibrates. but not to nearly the same extent, and the changes in pressure reading remain more consistant

BUT,DON,T be thinking that either is a mandatory huge improvement, it may or may not help the power, the degree of restriction, displacement, compression ratio, cam timing and the efficiency of the headers has a good deal to do with your results, and sticking restrictive mufflers on past the (X) or (H) can effectively kill most of the potential benefits
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: building custom headers

Postby grumpyvette » August 5th, 2011, 2:59 pm

these pictures might help


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http://www.icengineworks.com/icewtools.htm

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IF YOUR WELDING STAINLESS USE A MINIMUM 16GA 18 GA is too THIN, FOR STAINLESS HEADERS OR EXHAUST PIPE, AND DON,T FORGET TO PURGE THE BACK GAS WHEN WELDING , and 321 is superior to 304 stainless
http://www.kengineering.info/header%20f ... rticle.htm

http://www.stainlessheaders.com/index.aspx

http://www.magnumforceracing.com/store4/ubends.htm

http://www.holley.com/types/Miscellaneo ... onents.asp

http://www.jegs.com/p/Hooker-Headers/Ho ... 6/10002/-1


IF YOU WELD STAINLESS EXHAUST PIPE without a back flush you can get weld crystallizing or SUGARING , an ARGON back flush and taping both ends to exclude oxygen helps reduce this significantly as will tig paste

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http://www.solarflux.com/Pages/Productinfo.html
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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: building custom headers

Postby grumpyvette » December 14th, 2011, 11:16 am

http://www.hotrod.com/techarticles/hrdp ... ipe_dream/
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There are twisted individuals out there who don't want to put a Chevy in a Chevy and others who think the factory engine location doesn't always cut it when striving for improved engine fitment and the ideal front-to-rear weight bias. Either scenario leads to a place many of us never want to go when working with an oddball engine and chassis combination-the realm of the custom header build. Time-consuming, frustrating, and ultimately very expensive, custom pipes are the bane of every hot rodder's existence, unless he owns a tube bender and has a knack for geometry. Even then, every header-building artist still has a scrap pile of tube sections that didn't quite fit the project they were intended for. Wasteful. That nonsense ends today. Go ahead, stuff a BMW V12 into a Nash Metropolitan or slide your Hemi backwards in the chassis a few inches. With Icengineworks' precision header modeling system, even the novice fabricator can design and build his own pipes correctly the first time.

The kit is composed of rubber connectors that fit into a header flange to give a starting point for your primary pipe build. Interlocking plastic tubing sections of varying angles are marked to indicate the direction and orientation of one section to the next. You can literally twist together the primary pipes, snaking them around your project car's steering shaft, gearbox, firewall, control arms-whatever gets in the way. Once you settle on a header design, you can measure exactly how long the primary tubes are (the centerline length of each tube) and where to make the bends on a tubing bender. Or if you're on a budget and don't have a bender, you can simply buy tubing donuts or mandrel-bent, U-shaped lengths of tubing, and the modeling kit will show you exactly where to cut each tube so you can weld all the individual sections together to make your custom header. An included jig makes cutting the tubing on a vertical bandsaw easy enough for almost anyone to build his own pipes without making an expensive pile of scrap. The kit is as pricey as a set of coated headers but pays for itself the second time you use it.
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: building custom headers

Postby grumpyvette » July 8th, 2014, 3:16 pm

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: building custom headers

Postby grumpyvette » March 12th, 2015, 12:34 pm

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: building custom headers

Postby 87vette81big » March 12th, 2015, 1:07 pm

Be a fun project to take on someday building custom headers for myself Grumpy.
Time is limited and funds not there.
For now adapting headers to fit is what I have done.
Cut & move header tubes.
Welded myself.
#1 Reason I abandoned the Corvette Racecar project.
I have 2 sets if Hooker #4202 Race headers for the 1970 Trans Am.
I know they perform.
2" primary & 3-1/2 collectors.
Tuned Nice. Near equal lengths.
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