Darton MID Sleeves for FA20 BRZ/FRS (800-890) Darton

Darton MID series sleeve kit for the FA20D/4U-GSE BRZ, FRS & 86 engines feature the greatest cooling capacity of any system. Allows even greater boost without unusual cam profiles to scavenge exhaust heat (helps control detonation). Even larger bore capability is now possible 86mm to 90mm MAX. Includes a full set of 4 sleeves.

Vehicle Fitment:
Subaru FA20D / Toyota 4U-GSE
2013+ Subaru BRZ
2013+ Scion FR-S
2017+ Toyota 86

Includes:
(4) Sleeves

Features:
• Improved block integral strength
• Improved cooling
• “Wet sleeve” replace-ability
• Increased horsepower output potential
• Superior oil and compression control
• Street or strip application
• Kits can be installed by your local machine shop
• Full installation manual with every kit sale
• High boost and horsepower potential · Superior cylinder sealing and ring wear
• Bulletproof Darton ductile iron, 130,000 psi tensile strength

More from Darton:
Many production cast iron and aluminum blocks suffer from a design weakness of cylinder stability by nature of poor support at the upper deck area. The manufacturing process of “cast in sleeves” provides for economy of scale in low horsepower engines, but does not accommodate high horsepower, high boost, or larger bore sizes.

Darton has engineered a superior solution by using a unique designed cylinder sleeve which when siamesed and nested, creates a solid deck of sleeve flanges held in tension, reinforcing the upper deck area and provides for in-field replacement with what we call Modular Integrated Deck (MID). In addition, Darton designs’ manage and enhance water flow from block to head to promote stability of cooling and all sleeves are of the “Wet” design.

The enhanced water flow in and around the flange area is possible because of ported water flow control engineering we call “swirl coolant technology”. This process begins with specific engineering models of respective cylinder head and combustion chamber designs and then we promote increased flow of water in those areas of the upper sleeve area subjected to the most heat. There is a different engineering model for each engine and cylinder design. While heat is generally considered to translate into energy, high resident heat in the combustion chamber can lead to detonation, the single highest cause of engine failure in the high horsepower regimes. High RPM normally translates into efficient scavenging of air-flow but during misfires or incomplete flame propagation, high cylinder pressures and temperatures are created. Our MID design compensates for this high resident heat soak condition.

In the normal dry sleeve installation the cooling medium, water, must transfer heat absorption through block material and sleeves, which may be dissimilar metals. When dry sleeves are pressed in with interference fit, the materials interface is not perfect which further exacerbates heat transfer. This thermal conductivity is inefficient and as more heat is generated, the combustion process is compromised. Even in wet sleeve designs of the past, water is never efficiently processed or flowed between the block and head to provide for maximum heat dissipation in the combustion chamber. Inherent in open or closed deck engine blocks of cast iron or aluminum is a certain amount of water stagnation. This is like pouring water through a funnel, there is really no flow or velocity until the water exits the spigot. In the case of blocks and heads, the casting ports are designed for ease of casting not efficient flow. Now with Darton’s “MID”, swirl coolant technology the cooling medium is ported and directed to significantly improve heat transfer where it is needed most, in the upper cylinder wall/flange area.