Also available in: 3.000" Inlet/Outlet (12030) | 6.000" Body / 3.000" Inlet-Outlet (12230)
HIGH-FLOW EXHAUST CLEANUP FOR 2.500" DIESEL SYSTEMS — 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 (12025) is the 2.500" version of the 12030 Diesel Oxidation Catalyst — the compact member of the diesel line, sized for smaller-displacement diesels and tighter exhaust routing. The 2.500" inlet/outlet welds into 2.500" tubing, and the 200 CPSI S-Wound metallic substrate keeps restriction low while cleaning up exhaust odor and haze on custom builds.
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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Compact 2.500" inlet/outlet — the smallest DOC in the line, for tighter routing and smaller-displacement diesels
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200 CPSI S-Wound metallic substrate, nickel-lined and furnace-brazed with Double-Lock canning
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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: 2.500"
- 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 running 2.500" tubing — smaller diesels, swaps, and off-road rigs where factory aftertreatment has been replaced and compliance is not required. Running 3.000" tubing? See the DOC 3.000" (12030), or the 6.000"-body DOC (12230) for maximum substrate area.
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 2.500" 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.
