Also available in: 6.000" Body / 3.000" Inlet-Outlet (12230)
HIGH-FLOW EXHAUST CLEANUP FOR CUSTOM DIESEL BUILDS — G-SPORT DOC (DIESEL OXIDATION CATALYST)
NOTE: G-Sport DOCs carry a lighter loaded catalyst and are not EPA compliant. They are intended for custom and motorsport diesel applications where emissions compliance is not required.
The G-Sport DOC (12030) is a Diesel Oxidation Catalyst: the diesel-specific member of the G-Sport line, built to clean up diesel exhaust on custom and competition builds. A 3.000" inlet/outlet welds into common diesel downpipe and exhaust tubing, and the 200 CPSI S-Wound metallic substrate keeps restriction low on high-flow diesel systems.
WHAT IS A DIESEL OXIDATION CATALYST?
Unlike the three-way catalysts used on gas engines, a DOC is an oxidation catalyst built for the lean exhaust of a diesel. Its precious-metal coating oxidizes carbon monoxide and unburned hydrocarbons — the compounds behind diesel smoke smell and haze — into carbon dioxide and water as exhaust passes through. The result on a custom diesel build is a noticeable cleanup in exhaust odor and visible emissions without the flow penalty of factory aftertreatment, in a compact weld-in package built on GESi's proven S-Wound core and stainless construction.
FEATURES
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Diesel-specific oxidation catalyst — targets CO and unburned hydrocarbons in lean diesel exhaust
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200 CPSI S-Wound metallic substrate — low restriction for high-flow diesel systems
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Nickel-lined, furnace-brazed core with Double-Lock canning — the substrate cannot telescope or fail under boost
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300 Series stainless steel construction inside and out; withstands spikes up to 1,600°F
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Not EPA compliant — for custom and motorsport diesel applications only
SPECIFICATIONS
- Type: Diesel Oxidation Catalyst (DOC)
- Inlet/Outlet: 3.000"
- Body Diameter: 4.000" OD
- Overall Length: 7.250" (±0.125")
- Cell Count: 200 CPSI
- HP Rating: N/A (application-rated, not horsepower-tiered)
- Substrate: S-Wound metallic, furnace-brazed
- Material: 300 Series stainless steel
- EPA Compliant: No — custom and motorsport diesel applications only
- Weight: 2.86 lbs
- Connection: Welding Required
APPLICATIONS & FITMENT
Built for custom and competition diesel exhaust systems — race trucks, pullers, off-road rigs, and custom builds running 3.000" tubing where factory aftertreatment has been replaced and compliance is not required. Running larger tubing or wanting maximum substrate area? The 6.000"-body DOC (12230) carries a much larger core with the same 3.000" inlet/outlet.
For the full G-Sport range, see Understanding the G-Sport Catalytic Converter Lineup and our G-Sport FAQ.
INSTALLATION NOTES
This is a weld-in unit for 3.000" exhaust tubing. Install with leak-free joints, downstream of the turbo where exhaust temperatures remain high enough for the catalyst to work effectively, and with adequate clearance from wiring and heat-sensitive components. Full best practices are in our G-Sport Installation Guidelines.
Not sure which DOC suits your diesel build? Email us at support@aceraceparts.com with your platform, tubing size, and how the truck is used and we will point you to the right part.
