Drivetrain› Automatic Transmissions and Components

Circle

258mm Pro Series Torque Converter for 4R100/E4OD

$2,549.00

SKU: 31-13-05

Special Order
Special Order
Ships in 4–6 weeks
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Overview

The Circle D 4R100/E4OD Pro Series torque converter is a 258mm unit designed for high horsepower applications. It features a smaller 10 1/4" core for improved launch and good top-end efficiency.

Construction includes 100 square inches of clutch lining for WOT lock-up, furnace brazing, and hand TIG welding. It also utilizes Torrington bearings, a billet front cover, and a billet piston. The impeller hub is flanged for durability, and the assembly is hand-assembled to exacting tolerances. This converter boasts a lightweight yet strong design.
Show original supplier description
The Circle D Specialties 258mm Pro Series 4R100/E4OD Torque Converter is engineered to enhance the performance of Ford transmissions, particularly for applications like the turbo Lightning where improved launch is critical. Its 10 1/4" core size facilitates a quicker launch while maintaining efficient top-end performance. Constructed with a focus on durability and performance, this torque converter boasts 100 square inches of clutch lining for robust Wide Open Throttle (WOT) lock-up. The construction utilizes furnace brazing and meticulous hand TIG welding. Key internal components include Torrington bearings and a billet piston, complemented by a billet front cover for added strength. The flanged style impeller hub enhances anti-flex durability, ensuring reliable operation under demanding conditions. Each converter is hand-assembled to precise tolerances, resulting in a lightweight yet exceptionally strong unit. Buyers can select from various stall speed options, ranging from 2500 RPM to 3700 RPM, and choose between the 4R100 (6x11.375") or E4OD (4x11.375") bolt patterns. Additionally, options for a mechanical diode sprag are available for enhanced performance characteristics. Due to the custom nature of this product, it is custom manufactured with a production time of 5-6 weeks.

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

Fitment

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Specifications

BrandCircle
Part Number31-13-05
CategoryDrivetrain
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Returns & Fitment

Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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