This exhaust manifold and silencer was designed to optimize each performance criteria:

The Exhaust :

- The original gas recuperation system has been replaced with a 4 branch manifold.

- By taking into account the engine’s characteristics (bore, stroke, opening and closing of valves…) and the available place inside the engine compartment, an optimal theoretical length was calculated for each primary pipe. To insure the same optimal output for each cylinder, each pipe has the same volumic length, and neutral fiber.

- An identical length of primary pipes ensures an equivalent output for each cylinder. This in turn reduces fuel consumption, diminishes engine vibrations, by as much as 60%,, which leads to a higher level of comfort inside the cockpit.

- Cylinder head flanges are made from 316 L stainless steel. Primary pipes and collectors are made from inconel 625 sheets. With a high thermal resistance, this alloy insures an excellent reliability for the exhaust system.

The Silencer

1- In order to keep the aero dynamical envelope as « clean » as possible, the silencer is integrated inside the engine compartment, in regards of the environment and the spatial availability.

2- The silencer works by diffraction, with a chamber made out of a drilled sheet of metal. The absorption is done through padding around the relaxation chamber, made from layers of metal sheeting. The acoustic gain, approx. 15%, is mainly due to the loss of high frequencies, which significantly improves the acoustics’ onboard.

3- This exhaust system includes a cabin heater, which is as efficient as two original cabin heaters, thanks to a higher thermal exchange surface.

4- Finally the manifolds and silencer are attached to the engine itself. This prevents having problems with the engine movement compared to the cockpit, which can sometimes induce abnormal wear and even breakage of the linking tubes, in spite of their mobility. Our exhaust system was designed and made thinking in terms of complimentarity, in order to have a homogeneous operating envelope. This is crucial in obtaining good reliability.

Before proceeding with the assembly of the manifold
– silencer package, you must :
- dismantle the lower engine cowling
- dismantle the boas which bring fresh air to the cabin and carburetor heating boxes.
- dismantle the gas control support plate.

1 The Manifold

- fix the primary pipes (2) onto the cylinder reach, without forgetting the gasket
- insert the auto-lock washers and slightly turn the nuts without tightening.
- Apply high temperature grease onto the 4 branch manifold fittings
- Fit the 4 branch manifold by matching the numbers on the flanges.
- apply the 3 M5 screws (14) and auto lock nuts (15)
- tighten the cylinder head flange bolts (1)
- tighten the manifold screws (14) then unscrew by a quarter turn.

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2 The Silencer
- unscrew the 4 crankcase screws where the silencer tie rods will be installed
- Fit the left silencer support assembly 708 710 703
- Fit the right silencer support assembly 705 707 701

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- Apply high temperature grease onto the silencer fitting. (7)
- fit the silencer.
- put in place the left inferior silencer clamp (704) by using two screws (716) and nuts (717)
- put in place the right inferior silencer clamp (702) by using two screws (716) and nuts (717)
- tighten all the screws - plug in the fresh air boa intake (713) onto the right cabin heater box (711)
- tighten the cerflex clamp (719)
- plug in the hot air boa (714) onto the left cabin heater box (712)
- install and tighten the cerflex clamp (719)
- plug the other extremity of the hot air boa (714) onto the cabin vent against the firewall
- install and tighten the cerflex clamp (719)
- plug off the other cabin vent on the firewall with the cabin heater plug (715)
- install and tighten the cerflex clamp (719)
- Apply high temperature grease onto the outlet pipe fitting (5)
- fit the outlet pipe (5) onto the silencer (7)
- slide the outlet pipe support clamp (720) until the fixing flange of the inferior left clamp. (704)
- fix the M5 screw (14) then the auto lock bolt M5 (15) and tighten.

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- plug in one extremity of the carburetor heating boa (17) onto the opening of the carburetor heating box (10)
- install and tighten the cerflex clamp (719)
- plug in the other extremity of the boa (17) onto the intake pipe.
- install and tighten the cerflex clamp (719)
- unplug the fuel tube
- protect the fuel tube with the sheath (16)
- put the fuel tube back without forgetting the gaskets. Tighten.
- attach the new gas control plate (18) on the original place.
- put the gas controls back on and tighten all the screws
- Check that all the fuel pipes or electrical cables are far away from the exhaust manifold(2). If not isolate with thermal protection every part that might be deteriorated or divert with a clamp.

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