Stock Two-Valve intakes are...
Stock Two-Valve intakes are made of plastic and feature long runners. They work fine with bolt-on items, but once you turn up the power, the manifold becomes very restrictive.
This month, we'll take a look at the new TFS Two-Valve intake manifold and unlock the mystery behind the aluminum. The Internet and various magazines have been buzzing with truths, half-truths, and flat-out incorrect info on this new intake manifold. We first saw the piece at the Performance Racing Industry show (commonly called PRI) in Orlando, Florida, where it was announced with great enthusiasm. After several delays in production, the intake manifold slowly hit the market this past summer. Still, with back-orders and long wait lists, there wasn't much data from other shops for us to study. However, thanks to Mike Dezotell of Dez Racing, we were able to test an intake without the required wait time. He had ordered an intake a while back to test in-house, and TFS delivered it just before we went to press with this issue. Finally, we were able to independently test this new intake manifold.
As we mentioned earlier, all of the parts have to work together in order for a combination to produce the power it was intended to. Generally, long-runner intakes work great in the low and midrange, and short-runner manifolds are better for producing power higher in the rpm range. Many of the Two-Valve intakes feature short runners, which moves the powerband up too high for most street engines. In short, the stock intake, with some minor enhancements, works pretty good up to about 400-450 hp.
Dezotell holds up the lower...
Dezotell holds up the lower manifold, exposing the guts of the intake. The runners are much shorter than stock.
Due to the variety of rumors and assumptions about this manifold, we chose to go with a middle-of-the-road Two-Valve engine. The test subject, belonging to Keith Johnson, has a stock engine that breathes more air thanks to a ProCharger P1SC (12 psi of boost), Anderson Ford Motorsport cams, a TFS upper plenum (with stock intake), a BBK 70mm throttle body, Bassani shorty headers, an x pipe system, an axle-back exhaust, and a Tremec transmission with a Centerforce DFX clutch. In this trim, the car produced 441 rwhp and 413 rwtq.
Some of the rumors stated this intake was more suited for a car that has ported heads and makes far more power. Johnson's ride didn't have heads, but the airflow through his engine has been enhanced with the camshafts, exhaust, and blower. Logically, the next step is to add a set of ported heads to the fold, so upgrading the intake is easy to do and will suit him better in the future. We wanted to test the theory of this intake gaining power with ported heads only, and this car was perfect.
 Our first thought when looking...  Our first thought when looking at the topside of the lower manifold was, LS1 intake. Given TFS' involvement in the LS1 market, we wouldn't be surprised if some characteristics were carried over to this intake. |  Fittings, plugs, vacuum ports,...  Fittings, plugs, vacuum ports, EGR valve, and other parts are swapped onto the TFS intake before it's dropped onto the engine. |  Machie torques down the bottom...  Machie torques down the bottom cover to the lower intake manifold. |
 The upper plenum is ready...  The upper plenum is ready for action. TFS stated that a Track Heat upper manifold is due to be released this winter. It will use a single-blade throttle body. |  The stock and TFS intake openings...  The stock and TFS intake openings are identical; the cross-section is 1 1/2 inches, while the width checks in at 1 3/4 inches. That means if you run ported heads, you should consider port-matching them to the intake. |  Two people were needed to...  Two people were needed to drop the intake in place. Having two sets of hands helps clear stuff out of the way. |