Autometer 5 Sport-Comp 120 Mp

Product Overview

When it comes to the iconic look of a high-performance cockpit, nothing carries the prestige and reliability of the AutoMeter Sport-Comp series. The AutoMeter 5-inch Sport-Comp 120 MPH Mechanical Speedometer (ATM3994) is the gold standard for custom air-cooled Volkswagen builds, sand rails, and street-dominating dune buggies. Featuring the signature black face, bold white numbering, and a high-contrast red pointer, this gauge provides instant readability even in the harshest vibration environments. Whether you are tearing up the dunes in a Manx-style buggy or refining a custom Pro-Street Beetle, this speedometer delivers the professional-grade precision that AutoMeter has been known for since 1957. The 5-inch oversized diameter creates a commanding presence in your dashboard, ensuring that your speed and trip data are always front and center.

It is important to understand that this is a mechanical unit designed for serious custom applications. While it offers the classic mechanical movement that many purists prefer for its durability and "no-electronics-required" simplicity, it does feature a domestic-style 5/8-inch - 18 threaded cable input with a .104-inch square drive. This means it is not a "plug-and-play" replacement for a stock Volkswagen speedometer cable. However, for the dedicated builder, this gauge is the centerpiece of a high-end interior. It includes a resettable trip odometer, allowing you to track fuel stops or trail distances with ease. When you choose AutoMeter from Appletree Auto, you are not just buying a gauge; you are investing in a piece of racing heritage that is built to withstand the rigors of off-road abuse and high-performance street use.

Vehicle Fitment & Compatibility

This is a universal high-performance gauge designed for custom dashboard installations. While it is a favorite for the VW community, modification to the stock dash and a custom speedometer cable are required. It is commonly installed in:

• Volkswagen Beetle (All Years): Requires custom dashboard or oversized gauge pod.
• Volkswagen Karmann Ghia: Ideal for custom "three-gauge" performance layouts.
• Volkswagen Bus (Type 2): Frequently used in custom overhead or center consoles.
• Dune Buggies & Sand Rails: The industry standard for fiberglass Manx-style bodies and tube-chassis rails.
• Volkswagen Thing (Type 181): A rugged upgrade for modified military-style cruisers.
• Custom Street Rods: Perfect for any air-cooled build utilizing a domestic-style steering column or custom transaxle setup.

Technical Specifications

• Brand: AutoMeter
• Series: Sport-Comp
• Part Number: ATM3994
• Gauge Diameter: 5 Inches (127mm)
• Speed Range: 0 - 120 MPH
• Movement Type: Mechanical
• Input Thread: 5/8-inch - 18 Threaded Cable Input
• Drive Type: .104-inch Square Drive
• Face Color: Black
• Bezel Color: Silver / Brushed Aluminum
• Pointer Color: Fluorescent Red
• Lighting: Incandescent (Around the dial)
• Odometer: Integrated with Resettable Trip Meter

Expert Pro Tips from Appletree Auto

1. Solving the VW Cable Conflict

The most common question we get is, "Will this work with my stock VW cable?" The answer is no, but the solution is simple. Since the AutoMeter ATM3994 uses a domestic 5/8-inch threaded input, you will need to order a custom speedometer cable. You want a cable that features the standard Volkswagen "clip-on" or "screw-on" end for your front spindle (Type 1/3) or transaxle (Type 2), with the other end terminated in a 5/8-inch domestic fitting for the gauge. Many custom cable shops can build this for you in under 15 minutes if you provide the length. Don''t try to force the VW cable onto this gauge; you will strip the threads and ruin the precision movement.

2. Perfecting the 5-Inch Dashboard Cutout

Installing a 5-inch gauge in a standard VW dash requires precision. A stock Beetle speedometer hole is not the same size as this AutoMeter unit. If you are working with a fiberglass buggy dash, we highly recommend using a dedicated 5-inch hole saw and running the drill in reverse for the first few seconds to "score" the gel coatthis prevents chipping. For steel dashes, use a template and a nibbler or a high-quality hole saw with plenty of cutting oil. Ensure there is at least 3 inches of clearance behind the dash to accommodate the cable sweep, as mechanical cables do not like sharp 90-degree bends.

3. Accuracy and Tire Diameter

Because this is a mechanical speedometer, its accuracy is directly tied to your tire height and your transaxle''s drive gear ratio. If you have significantly upsized your rear tires for an off-road build, your speedometer will likely read slower than your actual speed. While modern GPS apps can help you "calibrate" your mental math, remember that mechanical gauges are calibrated for a specific number of cable revolutions per mile (usually 1,000 RPM at 60 MPH). If your speed is way off, you may need a ratio adapter (a small gearbox that sits inline with the cable) to correct the reading for your specific tire and gear combo.