Given the over 50 years of development time, you might think that every possible variation of small-block Chevy intake manifold has been done. When Air Flow Research decided to introduce a line of intake manifolds to complement its industry-leading cylinder heads, as you might imagine, innovation was a key objective. Here the company looked at the latest trends in OEM manifold manufacture, and the direction was clearly spelled out. Composite construction from polymer materials has entered the forefront, replacing traditional cast construction for this vital piece of the engine’s airflow system. The end product of this effort is AFR’s new Titan series of intake manifolds.
Why composites? Constructing a manifold from polymers offers technological advantages over a sand-cast component. For openers, because the polymer materials are molded in permanent dies, the precision of manufacture is substantially improved. What we get is a more consistent net shape to blueprint specifications, eliminating the inconsistencies of casting flash and core shift. The process produces identical parts every time, with smooth and clean surfaces throughout. This ensures that each runner will deliver the performance that it was designed for, without the variations that can rob horsepower. While composite material in the manufacture of intake manifolds seems to have many production advantages, the aftermarket has been slow to follow the OEMs in using this technique. The fact is that the tooling for such intake manifolds requires a much higher initial investment than that for a sand-cast aluminum component, making such a product a risky venture given the scale of aftermarket production. AFR showed the dedication to this technology that has made it a reality.
Just based upon the benefits noted above, composite manifolds seem to have enough going for them to be worth considering; however, this material has other advantages that make it naturally well suited to manifold construction. Of course, the obvious trait here is weight reduction. The composite material and construction techniques result in a manifold that is roughly half the weight of its aluminum counterparts, and when performance is the watchword, weight matters. Considering that the weight is ultimately removed from a high up and forward location on most vehicles, that is an advantage that translates to both straight line and handling applications.
A key innovation with the AFR Titan manifold system is the universal baseplate assembly. O
Less weight is a good thing, but we are saving the best for last, and that is the thermal properties of the composite material. Herein lays perhaps the key performance advantage of the polymer manifold. It is no secret that a cooler induction charge of air/fuel is one that packs more combustibles into the cylinder and makes more power. Everything from cool cans to iced-down intake manifolds is employed on the track in an effort to shave temperature from the charge in search of more power. In fact, at the AMSOIL Engine Masters Challenge event, some competitors go to extreme lengths to insulate the intake manifold from engine heat. The reality is that aluminum is a material that is a remarkable conductor of heat, literally soaking heat from any available source and rapidly discharging it to the mixture. This is why aluminum is a favored material for heat exchanges such as automotive radiators. This counterproductive trait of aluminum is one of the things that we have had to live with in intake manifold applications.
Sealing is taken care of by molded rubber seals. These are reusable and extremely effectiv
In contrast, a polymer material is a natural insulator, often used as the basis for insulating spacers and heat barriers. With a polymer manifold the heat transfer into the air/fuel mixture is dramatically reduced, allowing the latent heat of vaporization in the manifold to do its magic to cool the intake charge. In theory this characteristic leads to more power, and in a high-performance application, that is the ultimate goal. Tests at AFR show that the Titan polymer manifold runs 30 degrees cooler than conventional aluminum manifolds.
Just based upon the material, a favorable case can be made to recommend the AFR intake manifolds, but the innovation didn’t stop there. The engineers at AFR looked to add other design features that take this manifold system to the next level. The most striking of these features is the two-piece construction, consisting of a separate baseplate and spider assembly. The baseplate mounts to the intake valley, and houses the distributor and water crossover, while up top the runners and plenum are built into a separate spider molding. This configuration allows the spider to be removed or swapped without disturbing the distributor or draining the coolant.
The fittings going to coolant are corrosion-resistant brass alloy, double O-ringed to the
With the spider in place, a variety of top configurations can be easily bolted into place.
We completed the installation with a Holley 950 HP carb. The dual-plane exhibited very str