1-Output Improvement

This exhaust was designed in order to increase the engine output:

Photo Primary pipe, 4 branch manifold

Every cylinder outlet tube - primary tube - is 880 mm long. This is the optimal length considering the data from the manufacturer (length, bore, valve opening, etc.), and the available space inside the engine compartment.

Each pipe has the same volumic length, and neutral fiber. Identical lengths of primary pipes ensures an equivalent output for each cylinder, reduces fuel consumption, diminishes engine vibrations by approx. 60%, which leads to a higher level of comfort.

The 4 branch manifold – 4 primary pipes linked to a collector and to an outlet – enables a good mix of the gases, increases available torque and power.

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 to the exhaust.

Photo Cylinder head flange.

2-Le silencer

The silencer works along two principles :

A chamber made out of a drilled sheet of metal ensures the diffraction.

Padding around the relaxation chamber, made from layers of insulating material, enable the absorption.

The acoustic gain, of approx. 15%, due mainly to the loss of high frequencies, significantly improves the acoustics’ onboard.

3-Silencer mounting

The available space inside the engine compartment is not sufficient to receive the silencer: it is fastened under the cockpit.

The cylinder head flanges insure the rigidity of the collector’s fastening on the engine.

The engine mounted on silent blocks has a certain mobility compared to the cockpit, during cruising for instance.

All the conditions put together imply a specific stud, and the right build between the collector and the silencer.

Photo Screw and fastening bolt of the silencer Vertical tie rods Silencer clamp.

A twin ball joint pipe between the outlet pipe and the silencer compensate vertical and lateral movements

During manufacturing great care is taken for the sealing of the twin ball joint, without reducing the mobility

Small vertical tie rods link the silencer clamps with the cockpit. They compensate lengthwise movements of the silencer.

Structural elements which support the silencers are made out of 15CDV6T, which is used in aeronautics for mechanic-welded components. Surface treatment prevents them from corroding

Paulstra type supple ball joints enable a vibration free link up between the tie rods and the under cockpit supports.This combination of mechanical elements enables mobility between the collector and the silencer, limits mechanical constraints, and improves global reliability

Exhaust manifolds

Dismantle the original gas collector box.

Attach the primary pipes onto the cylinder heads, not forgetting the gaskets.

Fit the 4 branch manifold by matching the numbers engraved on the pipes and the lugs.

Put the screws and tighten.

Install the bracket attached the outlet pipe clamp, onto the engine casing.

2) Plug in the carburetor heating pipe onto the hot air box 18 which is attached to one of the primary pipes.

Silencer

Drill holes into the cockpit for the silencer mounting, following the information on the plans attached (ref : Monet 2 et Monet 4)

Install the support and silencer assembly under the cockpit

Fit the supple ball joint pipe 13 onto the outlet pipe 4, after having slid the silencer 9 to the back in its clamps. Be careful that both parts are properly pushed in. Tighten the fitting screw. Slide the silencer to the front, and fit it into the supple ball joint pipe. Tighten the fitting screw.Tighten the silencer clamps 10 and 11, after having checked the tie rods 12 are vertical.