Also available: HO 4.000" Core (50002) | Fabricator 6-Pack (685002)
850HP OF EPA-COMPLIANT FLOW, CORE ONLY — G-SPORT GEN1 ADVANCED UHO CORE
The G-Sport Gen1 Advanced UHO (Ultra High Output) Catalytic Converter Core (85002) packs an 850hp-per-core rating into a bare 4.500" OD x 4.000" long canister built for full custom integration on 1996–2016 OBD1/OBD2 vehicles. The larger body carries substantially more substrate cross-section than the HO core, and the 300 CPSI cell density gives it the most open flow area in the Gen1 range.
This is the catalytic core only — transition cones are sold separately. The matching cone for a 4.500" OD body is the 3.000" Transition Cone (94530), or you can fabricate your own transitions.
The GEN1 Advanced series pairs GESi's proven S-Wound metallic substrate with their proprietary precious-metal wash coat, which typically keeps catalyst-efficiency check engine lights off on 2016-and-older OBD systems. Building a 2017 or newer vehicle? Use the Gen2 UHO Core (85200) instead.
FEATURES
- Rated up to 850hp per core — 4.500" body for maximum substrate flow area
- Core-only format for full custom exhaust integration — weld directly into your system
- 300 CPSI S-Wound metallic substrate — thinner cell walls than ceramic and a lower cell density for maximum flow
- Nickel-lined, furnace-brazed substrate locked to its stainless mantle — will not telescope or fail under boost
- 300 Series stainless steel construction; withstands exhaust temperature spikes up to 1,600°F
- EPA compliant — third-party lab tested (not CARB certified; not for use on emissions-controlled vehicles in California)
SPECIFICATIONS
- Sold As: Catalytic core only (transition cones sold separately)
- Body Diameter: 4.500" OD
- Overall Length: 4.000" (±0.125")
- Cell Count: 300 CPSI
- HP Rating: up to 850hp per core (per exhaust bank)
- Substrate: S-Wound metallic, furnace-brazed
- Material: 300 Series stainless steel
- EPA Compliant: Yes (not CARB certified)
- Weight: 2.52 lbs
- Connection: Welding Required
PERFORMANCE
In instrumented dyno testing with pressure probes upstream and downstream of the substrate, a properly sized G-Sport high-flow catalytic converter produced horsepower and torque curves identical to a straight pipe, with no measurable pressure drop across the core. Emissions reduction runs up to 99% for carbon monoxide, 98% for nitrogen oxides, and 95% for hydrocarbons.
APPLICATIONS & FITMENT
Choose the Gen1 UHO core for custom builds between 500hp and 850hp per exhaust bank on 1996–2016 vehicles. Past 850hp, the Gen2-only UHO+ 5.000" core (85500, 1,000hp) and UHOX 6.000" core (85600, 1,200hp) are compatible with all model years. Prefer a weld-ready converter with cones already installed? See the Gen1 UHO 3.000" (85032) and Gen1 UHO 4.000" (85042) assemblies. Gen1's extra flow also makes this core the recommended choice for the unmonitored secondary position in two-converter-per-bank systems — even on 2017+ vehicles with a Gen2 primary.
For the full selection guide, see Understanding the G-Sport Catalytic Converter Lineup and our G-Sport FAQ.
INSTALLATION NOTES
This core welds into your system via the 94530 transition cone or custom-fabricated transitions. For best catalyst light-off and CEL prevention, install it as close to the OEM converter location as practical — on custom systems, within 8"–24" of the turbo outlet or header collector. In dual-bank systems, run the same core model on both banks; mixing generations or sizes between banks can cause uneven backpressure and inconsistent O2 readings. Full best practices, common mistakes, and a pre-flight checklist are in our G-Sport Installation Guidelines.
Not sure which generation or output tier your build needs? Email us at support@aceraceparts.com with your platform, power goal, and tubing size and we will point you to the right part.