Spark Exhaust dB Killer Rectangular 70 mm Open Universal G9920

The short rectangular insert. Seventy millimetres instead of a hundred and fifty, and a much larger opening — forty-seven by twenty-six against forty-one by fifteen.

Key Features

• dB killer for Spark rectangular silencers.
• 59.8 × 36.5 mm outer, 47 × 26 mm internal opening.
• 70 mm long.
• Open type, no perforation.
• Stainless steel, removable.
• Spark part number G9920, made in Mantova, Italy.

The Light Restriction

Compared with the long rectangular insert, this one barely narrows the exit: its opening is more than twice the area. What it does is take the sharpest edge off the note without costing the engine anything measurable.

That is the right choice when a machine is already close to a limit, or when the owner wants the exhaust civilised for a road ride rather than silenced for scrutineering.

Seventy Millimetres of Case

The other reason to choose it is space. Not every rectangular silencer has a hundred and fifty millimetres of straight section behind the outlet; a shorter insert fits where a long one physically cannot.

Measure before ordering. It is the one check that decides which of the two articles you need.

Two Inserts, One Family

Spark's rectangular cases take either this or G9915. The seat dimensions differ by less than a millimetre — 36.5 here against 35.8 there — so the outer body is not the distinguishing feature. Length and opening are.

Fitting

From the outlet, silencer in place, hand tools. A rectangular insert can only go in one way round, which removes the most common way of getting a db killer wrong.

Forty-Seven by Twenty-Six

That opening is close to the full section of the outlet, which is what makes this the light restriction of the two. Most of what it removes is the hard edge at the top of the range rather than the volume underneath it.

Legal Position

Where the silencer is homologated, the insert Spark supplied is part of the approved configuration and changing it puts the machine outside the certificate. Where the silencer is a racing article, no insert creates an approval. Both statements are worth reading twice before a technical inspection.