Turbo Accessories
T4/T6 COMBO 304 STAINLESS STEEL TURBO INLET FLANGE 3/8″ STANDARD
KEY FACT
The T4/T6 Combo Turbo Inlet Flange is a 3/8″ (9.5 mm) 304 Stainless Steel precision-machined component designed for both T4 and T6 footprint turbos using a single dual-pattern flange. CNC laser-cut to ±0.003-inch flatness, ASTM A240 304 certified, and priced at $52.00 — in stock with same-day dispatch.
SKU: TIFT4T6STAINLESSSTANDARD
It accepts both T4 and T6 bolt patterns in a single piece (8 × M10/M12), eliminating the need to source two separate flanges across a mixed-platform build. Manufactured from ASTM A240 304 stainless steel, it resists oxidation to 871°C (1600°F) — the industry-standard specification for street and track turbo builds. The 3/8-inch standard thickness suits the vast majority of passenger car and light truck builds. 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 | 3.32–4.09 in |
|---|---|
| Flange O.D. | 5.45 × 4.55 in |
| Bolt Pattern | 8 × M10/M12 |
| Thickness | 3/8″ (9.5 mm) |
| Max Temperature | 982°C / 1800°F |
| Material | 304 Stainless Steel |
| Standard | ASTM A240 304 |
| Surface Finish | Ra 1.6 μm mill finish |
| 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 YOUR SELECTION | 316 Stainless | Carbon Steel | 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 T4/T6 Combo 304 Stainless Steel Turbo Inlet Flange 3/8″ Standard
Does this flange fit my turbo?
Yes — the T4/T6 combo flange supports both T4-footprint (Garrett T04E, Precision 6262) and T6-footprint (Precision 88mm+, BW S475) turbos using its dual bolt pattern. It is not compatible with T3 or V-Band turbos.
Why should I choose 304 Stainless Steel for a turbo inlet flange?
304 stainless is the best all-round choice for most turbo builds. It resists heat to 871°C, welds easily, and costs significantly less than 316 or Inconel. It is ideal for gasoline engines running standard pump fuel or E30 and below.
Should I choose the 3/8-inch or 1/2-inch thickness?
For most builds, the 3/8-inch (9.5 mm) standard thickness is sufficient. Choose the 1/2-inch heavy-duty option only if you have a diesel engine, a large-displacement V8 with a rigid downpipe, or a setup that places significant cantilever stress on the flange joint.
How do I install the T4/T6 Combo turbo inlet flange?
Clean the turbo inlet face and remove all old gasket material. Align the flange with the 8 bolt holes and thread the M10/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 T4/T6 Combo 304 Stainless Steel Turbo Inlet Flange 3/8″ Standard?
The T4/T6 Combo 304 Stainless Steel Turbo Inlet Flange 3/8″ Standard is $52.00 per piece with free shipping on orders over $150. It is in stock and ships same day when ordered before 2 PM EST.