Ceramic, metallic, DPF, GPF, SCR: converter types and what they are worth
The types of catalytic converters and exhaust filters, how to recognise each one, and which types carry the most precious metal.
· Catalytic Price
- Ceramic three-way converters are the most common type and usually the richest in precious metal.
- Metallic converters use a wound steel foil and carry less metal per unit.
- DPF and GPF filters trap soot; they carry less precious metal than a classic catalyst but keep real value when complete.
- SCR units work with AdBlue and carry little or no platinum-group metal.
Ceramic converters
The classic three-way catalyst: a honeycomb ceramic block coated with platinum, palladium and rhodium, inside a steel shell. Petrol cars usually carry palladium and rhodium; older and diesel units lean towards platinum. These are the most common units and, weight for weight, usually the most valuable. Browse ceramic converters.
Metallic converters
Instead of ceramic, the metals are coated on a wound stainless-steel foil. You recognise it by the shiny metal honeycomb visible at the ends. Metallic units are light and the foil carries less precious metal, so prices are set per reference after the foil has been checked. Browse metallic converters.
Diesel particulate filters (DPF)
A DPF traps soot from a diesel engine in a dense filter block, often silicon carbide, which looks darker and heavier than a catalyst. It carries less precious metal than a three-way catalyst, so the price per piece is lower, but a complete, unbroken filter still has value. Many modern diesel units combine a catalyst and a filter in one shell: both parts count. Browse DPFs.
Gasoline particulate filters (GPF)
Fitted to petrol engines since about 2018, a GPF does for petrol what the DPF does for diesel. Like a DPF it holds less metal than the catalyst that usually sits in front of it.
Diesel oxidation catalysts (DOC)
A small unit fitted before the DPF; it carries platinum and palladium and is often worth selling despite its size.
SCR units
Selective catalytic reduction treats nitrogen oxides with AdBlue (urea). SCR blocks carry little or no platinum-group metal, so most have a low price or a price on request.
Monoliths and loose ceramic
The bare honeycomb block without its shell, or the broken pieces of it, are priced on weight and content. Keep the pieces: they are worth more than people think, and far more than the empty shell.
Which is which?
Look at the ends: a fine white or grey honeycomb means ceramic; a shiny metal honeycomb means metallic; a dark, dense block with alternately plugged channels means a particulate filter. When in doubt, send us photos.
Questions & answers
Is a DPF worth anything?
Yes. A complete, unbroken DPF carries less precious metal than a catalyst, but it still has a real price per piece in the catalogue.
Are metallic converters worth less than ceramic ones?
Usually, because the foil carries less metal. Each reference has its own price, so check the code.