Ultimate Harbor Freight Go Kart Engine Cost $8,725 to Build and It Started With a $950 Predator 670
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Building a fast go kart on a budget is one thing. Spending nearly $9,000 on a Harbor Freight Predator engine is something else entirely. Yet that is exactly what happened with an extreme Predator 670 project that pushed the limits of what this popular V twin platform can become.
The builder started with a standard $950 Predator 670 engine but replaced or upgraded almost every major component. The final cost reached around $8,725 after taxes and shipping, making it one of the most expensive Predator engine builds ever documented.
Predator 670 Build Goes Far Beyond a Budget Project
The Harbor Freight Predator 670 has earned a reputation among DIY builders because it is affordable, easy to maintain, and simple to install in many custom projects.
However, this build completely changed the engine’s original purpose. Instead of keeping costs low, the project focused on exploring the maximum potential of the Predator platform without worrying about the budget.
The result is a heavily modified turbocharged engine packed with premium aftermarket parts that would normally be found in much larger performance builds.
Every Major Upgrade Added to the Predator 670
The original engine was only the starting point. Almost every internal and external component received an upgrade.
Some of the biggest modifications include:
- Holley Sniper EFI system with proprietary USB cable
- Upgraded performance camshaft
- Garrett GT1241 style turbocharger with oiling accessories
- Billet pistons
- Billet connecting rods
- Billet flywheel
- Alternator kit
- Electronic ignition system
- Ported and milled cylinder heads with O ring modification
- Billet valve covers and rocker arms
- Fuel cell
- AN fuel lines
- Intercooler core
- Custom exhaust manifold
- Intake adapter
- Heavy duty valve springs and retainers
- Intercooler piping kit
- Silicone couplers and additional fittings
- Boost reference fuel pressure regulator
- High performance fuel pump
- Chromoly pushrods
By the end of the build, very little of the stock engine remained untouched.
Predator 670 Build Cost Breakdown
| Component | Estimated Cost |
|---|---|
| Predator 670 Engine | $950 |
| Holley Sniper EFI System | $1,400 |
| Performance Camshaft | $530 |
| Turbocharger | $400 |
| Turbo Oiling Accessories | $140 |
| Billet Pistons | $460 |
| Billet Connecting Rods | $290 |
| Alternator Kit | $400 |
| Billet Flywheel | $380 |
| Electronic Ignition | $340 |
| Cylinder Head Work | $300 |
| Billet Valve Covers and Rockers | $270 |
| Fuel Cell | $200 |
| AN Fuel Lines | $200 |
| Intercooler Core | $160 |
| Exhaust Manifold | $140 |
| Intake Adapter | $130 |
| Valve Springs and Retainers | $125 |
| Intercooler Pipe Kit | $110 |
| Pipe Couplers and Fittings | $120 |
| Fuel Pressure Regulator | $75 |
| Fuel Pump | $70 |
| Chromoly Pushrods | $65 |
The parts alone total approximately $7,225.
Once taxes and shipping costs are included, the complete investment climbs to roughly $8,725.
Turbo Setup Will Run Lower Boost
Interestingly, the builder already owns a supercharged Predator powered go kart.
For this new turbocharged setup, the planned boost pressure will be around 12 psi, slightly lower than the 14 psi used on the supercharged version.
No official horsepower figures have been released yet because the engine has not been tested on a dyno. As a result, its real world output remains unknown.
Could You Build Something Faster for Less Money?
From a value perspective, probably yes.
With nearly $9,000 invested, it would be possible to build a more powerful ATV engine or even purchase an entire performance vehicle that produces more horsepower.
Even the builder admits that this project was never about saving money. Instead, the goal was to see how far the Predator platform could be pushed while keeping its simple mounting design and easy serviceability.
Sometimes automotive projects are less about logic and more about curiosity. This build is a perfect example of that idea.
Why the Predator 670 Remains Popular
Despite this extreme project, most enthusiasts continue to choose the Predator 670 because of its practical advantages.
Some of its biggest strengths include:
- Affordable initial purchase price
- Widely available replacement parts
- Simple maintenance
- Easy installation in custom projects
- Strong aftermarket support
Those qualities make it one of the most common engines for go karts, mini bikes, and custom off road builds across the United States.
Final Thoughts
The Predator 670 started life as an affordable utility engine, but this project proves it can become something entirely different with enough time and money.
At a final cost of around $8,725, it is no longer a budget build by any definition. Still, it showcases what is possible when performance takes priority over practicality.
For most enthusiasts, buying a faster engine would make more financial sense. But for builders who enjoy experimenting and pushing mechanical limits, projects like this continue to inspire the automotive community.
Sources & References
1. Harbor Freight – Predator 670 V Twin Engine (Official)
Harbor Freight Predator 670 Engine
Official Harbor Freight website featuring Predator engines, specifications, pricing, and product details.
2. Holley Performance (Official)
Official source for the Holley Sniper EFI system and other performance fuel injection products.
3. Garrett Motion (Official)
Official manufacturer of Garrett turbochargers and turbocharging technology used in performance applications.
4. The Drive
Automotive news publication that reported on the extreme Predator 670 engine build and its estimated cost.
5. Harbor Freight Tools (Official Homepage)
Official retailer of Predator engines, tools, and equipment widely used by DIY builders in the United States.
6. Holley EFI Technical Resources
Official technical resource for Holley EFI products, installation guides, and performance information.
7. Garrett Turbo Technical Information
Garrett Turbo Technology Center
Official technical information on turbocharger design, performance, and engineering.
8. Predator Engine Community (Unofficial)
EC Carburetors Predator Engine Guide
Popular aftermarket resource covering Predator engine upgrades, tuning, and performance parts.
Frequently Asked Questions
How much did the Predator 670 engine build cost?
The complete project cost reached approximately $8,725 after including the price of the engine, aftermarket performance parts, taxes, and shipping charges.
What was the starting price of the Predator 670 engine?
The build started with a stock Harbor Freight Predator 670 V twin engine that costs around $950 before modifications.
Why did the total cost become so high?
The builder upgraded almost every major component with premium aftermarket parts, including electronic fuel injection, a turbocharger, billet internals, upgraded cylinder heads, custom fuel system components, and supporting hardware.
Which major upgrades were added to the Predator 670?
The engine received a Holley Sniper EFI system, turbocharger, billet pistons, billet connecting rods, billet flywheel, upgraded camshaft, electronic ignition, intercooler, custom exhaust manifold, fuel cell, chromoly pushrods, and several other performance upgrades.
How much did the performance parts alone cost?
The aftermarket components and upgrades totaled approximately $7,225 before taxes and shipping were added.
How much boost will the turbocharged Predator 670 run?
The planned turbo setup is expected to operate at around 12 psi of boost, which is slightly lower than the builder's existing supercharged Predator engine running at 14 psi.
Has the turbocharged Predator 670 been dyno tested?
No. At the time of the build update, the engine had not been tested on a dynamometer, so official horsepower and torque figures were not available.
Could a more powerful engine have been built for less money?
Yes. The builder acknowledged that a more powerful ATV engine or even a complete performance vehicle could have been obtained for a similar or lower budget. The project focused on exploring the limits of the Predator platform rather than achieving the best value.
Why is the Harbor Freight Predator 670 popular among builders?
The Predator 670 is popular because it is affordable, easy to install, simple to maintain, widely available, and supported by a large aftermarket parts industry.
Is an $8,725 Predator 670 build practical for most enthusiasts?
For most builders, investing nearly $9,000 into a Predator engine is not the most practical choice. However, projects like this demonstrate the engineering potential of the platform and inspire custom performance enthusiasts.
