What does the A/R ratio on a turbine housing mean?

The A/R ratio, or Area/Radius, on a turbine housing indicates the size of the exhaust gas passage relative to its distance from the center. A higher A/R like 1.28 generally means a larger passage, which helps the turbocharger breathe better at higher RPMs and can lead to more top-end power, though it might slightly delay initial spool-up compared to a smaller A/R.

What is the benefit of a divided turbine housing?

A divided turbine housing separates the exhaust gas pulses from each cylinder bank. This design helps prevent exhaust pulses from interfering with each other, leading to more efficient turbocharger operation, improved response, and potentially lower exhaust manifold backpressure.

What material is this turbine housing made from?

This Turbosmart turbine housing is constructed from cast iron. This material is chosen for its ability to handle the extreme heat and pressure generated by exhaust gases in a forced induction system, offering good durability and thermal stability.

Turbosmart Turbine Housing T4 Divided 1.28AR TS-19TH80C-D412

Name: Turbosmart Turbine Housing (80mm) T4 Divided 1.28AR
Brand: Turbosmart
SKU: turbosmart-turbosmart-turbine-housing-80mm-t4-divided-1-28ar-t14-960298
Price: 589.49 USD
Availability: BackOrder

Turbosmart Turbine Housing (80mm) T4 Divided 1.28AR

$589.49

On Backorder — Expected to ship by May 9, 2026

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

Turbosmart Turbine Housing (80mm) T4 Divided 1.28AR

Key Features

Turbosmart 80mm turbine housing for custom turbo builds.
Features a T4 divided inlet flange for efficient exhaust gas management.
Includes a 1.28 A/R (Area/Radius) ratio for balanced spool and top-end power.
Constructed from durable cast iron to withstand high temperatures and pressures.
Not CARB approved; cannot be shipped to California.

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Product Details

If you're building a custom turbo system or upgrading an existing one, selecting the right turbine housing is key to matching your turbocharger's performance to your engine's needs. This Turbosmart 80mm turbine housing, designed for a T4 divided inlet with a 1.28 A/R ratio, is built for serious performance applications where precise boost control and efficient exhaust gas flow are critical. It's a well-built component that helps you fine-tune your turbo's spool characteristics and top-end power delivery.

This housing features a robust cast iron construction, chosen for its durability and ability to withstand the high temperatures and pressures found in forced induction systems. The 80mm internal diameter is suitable for a range of turbocharger sizes, while the 1.28 A/R (Area/Radius) ratio offers a balance that promotes strong mid-range power and helps the turbocharger maintain boost at higher RPMs. The divided T4 inlet design is important for managing exhaust pulses, which can lead to improved turbocharger response and reduced exhaust manifold pressure compared to undivided setups. This attention to detail in its design helps ensure consistent performance and longevity.

When setting up a custom turbo system, the turbine housing is one of the most impactful choices you'll make for how your engine performs. This Turbosmart housing is a solid option for builders looking for a reliable and effective component to complete their turbocharger assembly. Remember that this part is not CARB approved and cannot be shipped to California.