Classic Inlines
603 W Pecos Ave
Mesa, AZ 85210

Using an Air Bypass Valve

When incorporating an air bypass valve into an induction system with individual butterflies, it is important to ensure that the air is evenly distributed between cylinders. To achieve even distribution we recommend that a suitable distribution manifold (see below) is placed between the bypass valve and the inlet tracts such that the tubes to each cylinder are all of the same length. The preferred position to introduce the air, particularly if the injector is not aimed directly at the back of the inlet valve, is near to the injector, thus providing optimum conditions for air/fuel mixing. Positioning the extra air inlet near the bottom of the tract should be avoided to prevent fuel flow-back under certain conditions.

Throttle bodies (including Direct-to-Head) which incorporate idle-bypass adjusters may be converted using a standard kit from Jenvey. The kit includes screw-in fittings to replace the adjusters, an air distribution manifold and 8mm (5/16") black nylon tubing for connection. The distribution manifold requires a ¼" BSPP female thread for attachment to the air valve. An adapter is available to convert the manifold to accept 19mm (3/4") push-on tube. Twin bodies without idle-bypass adjusters may be converted by carefully drilling through the starter hole provided with a 3.3mm drill. Other bodies (e.g. Single bore) require the manifold to be drilled and tapped to accept suitable fittings (see below) for the 8mm tube. Please see 'Pointers' above for the best position.

Connecting to the Air Bypass Valve
Some ABV's have a spigot, usually 19mm (3/4"), to which a hose may be attached. For these use our 19mm push-on adapter to connect the air distributor to the other end of the hose.
Most ABV's are designed to be bolted straight to a manifold and thus require an adaptor plate to be made. Tap this plate, in the appropriate position, with 1/4" BSPP thread to accept the Jenvey distributor.

Part Number
6 Cylinder Kit (1-DM3/222, 6-IBO1, 3-TN8060)
Air Distribution Manifold (1 per system)
Idle Bypass Insert (1 per cylinder)
Screw in Fitting (1/8" BSPT to 6mm ID tube)
Adaptor (manifold to 19mm push-on)
Black Nylon Tubing (8mm)

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