Header modeling kits from icengineworks help car builders and professional shops design and pre-fit full-size 3D model headers that can be easily reconfigured until a perfect fit is realized. This allows engine builders to construct the best possible header based on proven mathematical principles and the known dimensional requirements of their particular application. Duplicates to fit specific engine and chassis requirements can then be fashioned from metal tubing. The kits contain a complete set of actual-size ABS plastic modeling blocks shaped exactly like header tubing of the appropriate size. The blocks come in straight sections and curved sections that provide three- four- and six inch radius bends along the tubing centerline depending on the kit. Regardless of diameter, each straight block is one inch long and each curved block is also one inch long along its own arc centerline. The interlocking snap-connectors are of common size so you can even model stepped headers by snapping together pieces of differing diameters.
Individual modeling blocks are color-coded and labeled with their outside diameter and in the case of curved sections, the centerline radius of the bend. Indexing alignment arrows and rotational reference tick marks are molded into each piece for convenient computation of the degree of twist at any point in the design. Keep track of your primary length simply by counting the number of 1-inch segments in your design. Note that the two sections shown here each consists of three pieces.
To model a new header you snap the blocks together in any desired combination; rotating the curved pieces as required to make any required radius or direction change. You can construct a full-scale 3D model header that exactly fits your engine and chassis combination with easy access to spark plugs and appropriate clearance for engine compartment obstacles such as frame rails, starters, fuel pumps, alternators, power steering units, clutch linkage and other engine accessories. The process enables speedy corrections to meet your exact requirements as you refine your design. Individual pieces are marked on both ends with indexing arrows and tick marks so you can duplicate various sections in metal using appropriately cut lengths of straight, J-bend or U-bend tubing. The tick marks are spaced thirty degrees apart providing exact positioning references for transferring your designs to metal. Wherever you can keep the arrows aligned you can easily duplicate selected sections in metal with minimal tubing cuts. If you reverse direction for a new curve the alignment arrow for the next segment should be 180 degrees from the previous piece in order to achieve the fewest numbers of cuts in metal. If you twist a segment so that the arrows are not aligned you will have to add a cut in the metal tubing at that point to accommodate the new direction. The tick marks help you keep track of the degree of rotation whenever you are unable to keep the arrows aligned. As you evolve your design you will likely discover that there is more than one way to accomplish it. You can swap straight pieces and curved segments of differing radius to work your way around engine compartment obstacles while preserving approximately equal length primaries.
The correct header flange with appropriately sized starter tubes installed is required to start the modeling process. Each modeling kit comes with starter tube adapters that mate the modeling blocks to the starter tube.
When designing for a race car you’ll be targeting specific lengths and diameters to accommodate wave tuning in the engine’s application specific power band. The blocks allow you near infinite degrees of freedom to accomplish this with perfectly equal lengths or in some cases purposely unequal lengths on selected cylinders where you may be tuning to accommodate unequal length primary runners as found on most commercially available fixed dimension intake manifolds. In either case you can accomplish unlimited revisions in a short period of time without wasting any material. When you are satisfied with you design, you can break each primary down individually to match it in metal while the rest of your model remains intact on the engine. As you fabricate each section in metal you can check it on the model to verify accuracy. If you plan to make more duplicates, you can use the model to build a jig.
Regardless of the outside diameter, every individual modeling block has the same size snap connector so pieces can be mixed to model stepped headers if required. Support kits are also available so you can purchase extra blocks of any size to accommodate odd applications that may require more length or additional bends.
The only other requirement is a pair of the correct header flanges with short starter tubes or stubs installed. The starter tube adapters make the connection to the stubs via a rubber washer that expands as you tighten a bolt in the first modeling block. The beauty of this system is that it offers unlimited freedom to rotate extend or shorten any segment into the desired shape, length and direction to suit your exact requirements. This makes it particularly easy to model your way around various chassis obstructions and still achieve a near equal length header with perfectly aligned joints and bends. Each kit comes with design sheets illustrating J-bends and U-bends already broken into 1-inch segments. When you complete your design, simply count the segments on each primary and tick them off on the design sheet to determine how many bends you need to purchase.
With the header flange installed, the first modeling block is installed on each starter tube using the supplied Allen wrench to tighten the internal expansion washer. When properly tightened, the washer will retain the modeling block and still permit rotation to facilitate appropriate positioning of the first block, particularly when you start with a curved segment.
The company also offers separate fabrication aids in the form of a special aluminum pivot table and associated tube-cutting spacers of various radii for making precise tubing cuts that are always perpendicular to the tubing centerline regardless of radius. This permits your metal cuts to match the circular precision of the modeling blocks so you can fit the metal pieces together with extreme accuracy for precision welding. These components work with any ten inch or larger vertical band saw equipped with a rip fence. Other fabrication aids include clever tack welding clamps that grasp both pieces of tubing and lock them in perfect alignment for tacking. For those with no welding skills it is possible to piece together a complete set of headers using the clamps and then take the assembly to a qualified specialist for welding. Once you have created the ideal model header and transferred it to metal, you can break down the model and store the kit until the next header project comes along.
As you begin the modeling process you get a feel for the initial bends and packaging requirements. The system is infinitely adaptable so you can shape and reconfigure as many times as necessary to achieve the required header dimensions and appropriate fitment within the chassis.
The math involved is simple; consisting primarily of counting segments and noting the degree of twist and the appropriate lengths and radii. Of course you are limited to the available radii in the kits, but that is suitable for 95 % of all header building requirements and is further augmented by the ability to rotate individual pieces to the desired direction. The icengineworks kit has the potential to eliminate much if not all of the frustration of custom header building while allowing you to construct headers that functionally match the dimensional requirements of your specific racing application.
Icengineworks also makes the pivoting band-saw table and appropriate radius cutting spacers to accurately position your u-bends for cutting. The spacers enable cuts that are perfectly perpendicular to the centerline radius of the tubing, thus ensuring perfect alignment for minimal flow restrictions and ease of welding.