Turbo Accessories
T6 CARBON STEEL A36 TURBO INLET FLANGE 1/2″ HEAVY DUTY
KEY FACT
The T6 Turbo Inlet Flange is a 1/2″ (12.7 mm) Carbon Steel A36 precision-machined component designed for Precision 88mm/94mm, Borg Warner S400/S475, and Holset HX55. CNC laser-cut to ±0.003-inch flatness, ASTM A36 certified, and priced at $34.16 — in stock with same-day dispatch.
SKU: TIFT6CARBONSTEELHEAVYDUTY
It fits large-frame T6 turbos — Precision 88mm and 94mm, Borg Warner S400 and S475, and Holset HX55 — using the T6 4-bolt inlet pattern (4 × M12). Manufactured from ASTM A36 carbon steel and zinc-phosphate primed, it is the most cost-effective and weldable option — suited to builds that will be ceramic-coated after fabrication. The 1/2-inch heavy-duty thickness is recommended for diesel engines, large-displacement builds, and any setup with a rigid unsupported downpipe. Every flange is CNC laser-cut and surface-ground to ±0.003-inch flatness with bolt holes reamed to H7 tolerance, providing a gas-tight metal-to-metal seal without a gasket on properly prepared turbos.
✓ Free shipping on orders over $150
✓ Same-day dispatch on orders before 2 PM EST
✓ 30-day returns for unused items
✓ Pickup available in Miami, FL 33172 — by appointment
Technical Specifications
| Inlet Port Size | 4.09 × 3.19 in |
|---|---|
| Flange O.D. | 5.45 × 4.55 in |
| Bolt Pattern | 4 × M12 |
| Thickness | 1/2″ (12.7 mm) |
| Max Temperature | 982°C / 1800°F |
| Material | Carbon Steel A36 |
| Standard | ASTM A36 |
| Surface Finish | Zinc-phosphate primed |
| Flatness | ±0.003 in |
| Bore Tolerance | H7 reamed |
Material Comparison Guide
304 Stainless vs 316 Stainless vs Carbon Steel vs Inconel 625 — your selection is highlighted
| Specification | 304 Stainless | 316 Stainless | Carbon Steel YOUR SELECTION | Inconel 625 |
|---|---|---|---|---|
| Max Continuous Temp | 871°C (1600°F) | 925°C (1700°F) | 425°C (800°F) | 1093°C (2000°F) |
| Corrosion Resistance | Good | Excellent | Poor (needs coating) | Excellent |
| Weldability | Excellent | Excellent | Excellent | Good |
| Cost (relative) | $$ | $$$ | $ | $$$$ |
| Best For | Street / track | Marine / E85 / diesel | Budget builds / coated manifolds | Extreme boost / compound turbos |
| Standard | ASTM A240 304 | ASTM A240 316 | ASTM A36 | AMS 5666 |
| Recommended Gasket | Optional | Optional | Recommended | Optional |
Frequently Asked Questions
About the T6 Carbon Steel A36 Turbo Inlet Flange 1/2″ Heavy Duty
Does this flange fit my turbo?
Yes — the T6 inlet flange fits large-frame T6 turbos, including Precision 88mm and 94mm, Borg Warner S400, S475, and Holset HX55. It is not compatible with T3 or T4 footprint turbos.
Why should I choose Carbon Steel A36 for a turbo inlet flange?
Carbon steel A36 is the most weldable material and the lowest-cost option. It is the correct choice when the flange will be welded into a custom manifold that will then be ceramic-coated or powder-coated. It is not recommended for exposed installations.
Should I choose the 3/8-inch or 1/2-inch thickness?
The 1/2-inch (12.7 mm) heavy-duty thickness is correct for diesel engines, large-displacement V8 builds, and any application where the downpipe is rigid and places bending stress on the flange. For lighter gasoline builds, the standard 3/8-inch option saves weight and cost.
How do I install the T6 turbo inlet flange?
Clean the turbo inlet face and remove all old gasket material. Align the flange with the 4 bolt holes and thread the M12 bolts in finger-tight. Torque in a cross pattern to spec (M8: 18–25 Nm · M10: 30–40 Nm · M12: 50–65 Nm). A 1/16-inch Cometic MLS gasket is recommended on builds over 25 PSI.
Does this flange need a gasket?
A gasket is not strictly required — the face is ground to Ra 1.6 μm, which creates a metal-to-metal seal on most turbos. However, a 1/16-inch multi-layer steel (MLS) gasket is recommended for builds over 25 PSI boost or on turbos with minor surface irregularities.
What is the price of the T6 Carbon Steel A36 Turbo Inlet Flange 1/2″ Heavy Duty?
The T6 Carbon Steel A36 Turbo Inlet Flange 1/2″ Heavy Duty is $34.16 per piece with free shipping on orders over $150. It is in stock and ships same day when ordered before 2 PM EST.