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Air and Fuel› Fuel Injection Systems and Components - Electronic

Thundermax

ThunderMax ECM for Magnetti Marelli

Name: ThunderMax ECM for Magnetti Marelli
Brand: Thundermax
SKU: 309-312

$1,056.28

SKU: 309-312

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$100 Minimum Order

Non-Returnable Item

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Moderate — 2–4 hours

Overview

The ThunderMax ECM is a performance-driven, award-winning Engine Control Module designed exclusively for Magnetti Marelli–equipped EFI Harley-Davidson® motorcycles. This unit is specifically designed for Magnetti Marelli–equipped EFI models from 1995–1998, offering modern tuning control and reliability. The kit includes wide-band oxygen sensors, a plug-in harness, AutoTune module, and a USB communication cable.

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The ThunderMax 309-312 ECM is a performance-driven, award-winning module built exclusively for Magnetti Marelli–equipped EFI Harley-Davidson® motorcycles from model years 1995–1998. It brings modern tuning control and enhanced reliability to these early-generation EFI bikes. This kit arrives fully assembled and includes wide-band Bosch 5-wire oxygen sensors (18mm), a plug-in harness, AutoTune module, USB communication cable, a speed harness, and a tip sensor. The ThunderMax system utilizes proprietary AutoTune technology in a closed-loop control system to continuously adjust and perfect the air/fuel ratio in real time. It features fueling points mapped every 1.5° of throttle and every 256 RPM, along with a built-in barometric sensor for automatic altitude and ambient air compensation. Riders can utilize pre-loaded basemaps or fine-tune AFR maps, ignition timing, startup fuel, idle speed, rev limits, and speedometer calibration via the downloadable ThunderMax software. This product is intended for "RACE READY" vehicles only and is not legal for sale or use in the state of California or on any pollution-controlled vehicle. The ECM utilizes 18mm O₂ sensors, and if using a factory exhaust with 12mm ports, 18mm bungs will need to be welded in (bungs not included). The system comes with a 3-Year Factory Limited Warranty and is 100% engineered and made in the USA.

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

Brand	Thundermax
Part Number	309-312
Category	Air and Fuel

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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.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

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