What is the A/R ratio and why does it matter?

The A/R ratio (Area/Radius) of a turbine housing determines the flow rate of exhaust gases through the turbine wheel. A 0.64 A/R ratio, like in this housing, generally promotes faster turbocharger spool-up, meaning the turbo reaches full boost at lower engine RPMs.

What does 'Hi-Sil' cast iron mean for this housing?

Hi-Sil cast iron is a high-silicon content cast iron alloy. This material is well-built for turbocharger applications because it offers excellent resistance to thermal shock and high temperatures, helping to prevent cracking or warping under demanding conditions.

Why can't this part be shipped to California?

This turbine housing is not CARB (California Air Resources Board) approved. This means it does not meet California's strict emissions standards, and therefore, it cannot be legally shipped to or used in California.

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Specifications

Brand: Garrett
Part #: 827690-0003

Garrett GT28R Turbine Hsg Kit O/V T25 / 5-Bolt 0.64 A/R (Hi-Sil) (Special Order -Minimum Order Size)

Name: Garrett GT28R Turbine Hsg Kit O/V T25 / 5-Bolt 0.64 A/R (Hi-Sil) (Special Order -Minimum Order Size)
Brand: Garrett
SKU: garrett-garrett-gt28r-turbine-hsg-kit-o-v-t25-5-bolt-0-64-a-r-hi-sil-special-ord-t14-41085
Price: 410.30 USD
Availability: InStock

$410.30

Only 1 left in stock

Garrett GT28R Turbine Hsg Kit O/V T25 / 5-Bolt 0.64 A/R. Special order item, not CARB approved.

Key Features

Fits Garrett GT28R turbochargers.
Features an external wastegate port for boost control.
Includes a T25 or 5-bolt flange for exhaust manifold compatibility.
Has a 0.64 A/R ratio for quicker turbo spool.
Constructed from durable Hi-Sil cast iron for high-temperature resistance.
Part number 827690-0003.

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About this part

Product Details

This is the Garrett GT28R Turbine Housing Kit with an external wastegate port, designed for T25 or 5-bolt exhaust manifolds. It features a 0.64 A/R ratio, which helps to spool the turbocharger up quicker for improved throttle response, especially in lower RPM ranges. The housing is constructed from Hi-Sil cast iron, a well-built material known for its durability and resistance to high temperatures commonly found in turbocharger applications.

This kit is a special order item and may have a minimum order size, so please check before purchasing. It's important to note that this part is not CARB approved and cannot be shipped to California due to emissions regulations. This housing is intended for custom turbocharger builds or upgrades where precise control over boost and spool characteristics is desired.