65mm Billet 12AN Turbo Drain Oil Flange

Stop fighting ill-fitting drain flanges. This precision billet 12AN turbo drain flange is machined to match the bolt centre of mid-frame and large-frame turbochargers right out of the box.

Why Builders Choose This Flange

Purpose-Built Fitment

Machined to the bolt centre used by mid-frame turbos — 50mm (1.97") — and large-frame turbos such as the S400 — 50.8mm (2.00"). Bolt centre is the distance from the centre of one drain pad bolt hole to the centre of the other. Measure yours with calipers before ordering, because mid and large frame sit only about 1/32" apart.

65mm (2.56") Drain Length

The 65mm figure is the length of the drain — how far the drain body stands off the flange face before your hose connects. This is the middle of the three lengths we offer, with enough standoff to clear most obstructions without adding bulk. Also available in 35mm (1.38") for tight installs and 100mm (3.94") when you need to reach past a manifold, frame rail, or block accessory.

12AN Port for Maximum Oil Return Flow

A 12AN male port delivers a larger oil return passage than common -10AN alternatives, helping keep oil moving freely back to the sump and reducing the risk of centre-housing oil pooling, whether you are running a journal-bearing or ball-bearing unit.

Precision-Machined Sealing Surface

Billet construction means every sealing surface comes off the machine clean and true, giving you a reliable, leak-free interface between your turbo and your drain line with no chasing warped or porous castings.

Straight-Forward Installation

The direct bolt-on design fits without modification to your turbo's centre housing, making it an easy drop-in addition to any build, including street performance, track, or high-output applications.

Made by BSI Inc.

Produced by Black Sheep Industries, this flange is available with domestic North American pricing and shipping, with no expensive cross-border freight or surprise duties eating into your build budget.

Not sure which drain you need? See the S400 Turbo Oil Drain Guide for bolt centre measurement, length selection, and full sizing charts in metric and US standard.

FAQ

What turbochargers is this 65mm billet 12AN turbo drain flange made for?

It is machined for mid-frame and large-frame turbochargers — a 50mm (1.97") bolt centre on mid frame and 50.8mm (2.00") on large frame.

What does the 65mm refer to?

65mm (2.56") is the length of the drain, meaning how far the drain body stands off the flange face. It is a clearance and routing choice, not the bolt centre or the port size.

What is bolt centre?

Bolt centre is the distance from the centre of one bolt hole to the centre of the other on your turbo's oil drain pad. It identifies the frame class: 38mm (1.50") small frame, 50mm (1.97") mid frame, 50.8mm (2.00") large frame.

Does the 12AN port improve oil return flow?

The 12AN male port provides a larger oil return passage than common -10AN alternatives, helping oil move freely back to the sump and reducing the risk of centre-housing oil pooling.

Is this flange suitable for journal-bearing and ball-bearing turbos?

Yes. It can be used whether you are running a journal-bearing or ball-bearing unit.

Does installation require modifying the turbo centre housing?

No. The direct bolt-on design fits without modification to your turbo's centre housing.