Go kart Horsepower Everything you Need to Know

A measure of how much work is done. Usually, a reference to output power by any engine or motor. When it uses energy to do some work.

There are many types of horsepower and their standards but in this article. I will usually refer to the horsepower produced by the engine, its unit is expressed in (HP).

This Power is ascertained by the rate at which the amount of work is done per time. It’s one of the greatest physics phenomena which drives our modern-day automotive industry.

The calculation regarding horsepower is quite a rather simplistic one. It is calculated through the amount of power need to move 250 Kg 0.3 meter in 1 second or the power it needs to move 15,000 Kg 0.3 meter in 1 minute (Sixty Seconds).

Hence this became a standard to measure horsepower around the globe. The term “Horsepower” was initially coined by Scottish inventor James Watt in the 1770s.

How Does Horsepower Work in Go kart?

In go-kart, there are two quantities to be noted first one is Horsepower and the second one is torque. Both are different, horsepower is the measure of work done by the engine, and torque is the measure of the amount of force applied to that work.

Any engine with higher horsepower will sustain a higher amount of work once the go-kart starts moving. While torque will get your go-kart moving quickly In alternative words. We can say that engines with higher torque and lower horsepower will feel more powerful than engines with low torque and higher horsepower when accelerating from a stop position. But once at speed, the higher horsepower engine will accelerate much faster.

Consider yourself buying a go-kart, would you compromise on performance, maybe not, hence horsepower directly speaks to performance.

Go Karts and Horsepower (Co-Relation)

There are many types of engines for go-karts. But most engines have an air-cooling system, an overhead valve, a vertical shaft, and various other features. I will see a typical four or two strokes engine that will have an output of around 3.5hp to 20hp. Depending on the type of Go kart it is meant for.

The engine reviews are dependent on the cost-to-performance ratio, features, and build quality of the go-kart. These will provide you with a data-driven informed decision on the kind of Go kart with specific horsepower I am looking for.

The weight-to-power ratio is also an important aspect in the designing phase of a go-kart. This acts as a sole element as to why despite having a small engine or less horsepower they can go really fast. So hence better top speed, more responsive handling, and faster acceleration are benefits most gained with a high power-to-weight ratio.

For a car with a power output of 400Hp and weighs 1400 kg, the power-to-weight calculation will be as follows:

400 / 1400 = 0.28

Closer to this number of 1.0, you can then assume that the car has power that is equivalent to its weight. If the ratio is higher number, we can gain more speed, hence the better it is for the Go kart.

Horsepower calculation for a Go kart is as follows, it can have two computations, one with Torque and the other with weight.

The torque mentioned above is the amount of force applied for the engine to do work which is multiplied by the Speed (RPM) of the Go kart. 5252 is another common constant if the speed is in rpm and torque is in ft-lbf. If the units are different then first, we must make the unit conversion.

Calculating Horsepower for Go Kart with Example

Let us now consider the following example for sake of understanding, the horsepower of a go-kart that moves with a speed of 550 revolutions per minute and has a torque of 80 pound-foot.

Solution:
Given parameters in the problem are:
Torque = 80-pound foot
Speed = 550 revolutions per minute

Now we may apply the Horsepower formula as below:
Horsepower = (Torque×Speed)/5252

Substituting the known values, we get:
Horsepower = (80×550)/5252
= 44000/5252
= 8.37 HP
Therefore, the horsepower of the engine of the vehicle will be 8.37 HP.

Go Kart Engines Horsepower and Ratios

I will list down a list of best Go karts engines based on some key features. Which include Max Horsepower output, Cost to performance ratio, Displacement, and engine type.

As a Go-kart engine is the source of power and I need to consider the best-performing engine that is the most efficient.

Serial No. Go Kart Racing Engines Key Features
01 Tillotson 212cc • Electric Start
• 9+ HP at 3600 RPM
• 212 CC Displacement
• 4 Stroke OHV
• Weight: 38lbs
• Max torque: 9.5-10 ft-lb at 2500 RPM
02 Predator 6.5HP • Great Entry Level Engine
• 6.5 HP at 3600 RPM
• 212 CC Displacement
• 4 Stroke OHV
• Weight: 37.5lbs
• Max Torque 8-8.2 ft-lb at 2500 RPM
03 Lifan LF 168F-2BDQ • Automatic Shutdown Engine
• 1600-Hour Engine
• 6.5HP at 3600 RPM
• 196 CC Displacement
• 4 Stroke OHV Engine
• Weight: 43 lbs.
• Max Torque: 7.5-8 ft-lb at 2500 RPM
04 BILT HARD 301cc • EPA Compliant
• 10HP Fuel Efficient Engine
• High-Performance Racing
• 301 CC Displacement
• 4 Stroke OHV Engine
• Weight 57 lbs.
• Max Torque: 13.28 ft-lbs. at 2500 RPM
05 Briggs and Stratton 550 series • Efficient size-to-performance ratio
• Fuel-Efficient Engine
• 3.5HP Engine
• 127 CC Displacement
• 4 Stroke OHV Engine
• Weight: 28.7 lbs.
• Max Torque: 5.5 ft-lbs. at 2500 RPM
06 Alpha Works 7HP • Engine Shutoff Function
• Transistorized Magneto Ignition (TCI)
• 7HP Engine
• 209 CC Displacement
• 4 Stroke OHV Engine
• Weight: 32.6 lbs.
• Max torque: 8.85 ft-lbs. at 2500 RPM

This Data analysis leads us to an important question of how fast a 5 HP engine can go. Well to answer that, we need to analyze gear settings and the type of chain drive.

Which depends partly on how it’s geared. As far as a ¼ gear ratio with a direct chain drive with an average 5hp motor would give you around 25-30 mph but if the Kart drives on a grassy surface it might ride on a maximum speed of 20mph.

Chain Sizes for Horsepower

To provide a more fruitful understanding of how speed works in Go Karts. I will provide an insightful understanding of Chain sizes ascertaining factors such as Pitch, Roller Width, and Tensile Strength.

A Go kart with a wronged size chain will lead to sprocket wear, chain stretching, and eventually chain break. So hence it would be wise to choose a chain that can handle your Go Karts engine power and make an informed decision according to the following data provided.

For a rule of thumb, Engine Power that is less than 20 HP should use chain codes of 35, 40, 41, or 420 roller chain but if the power produced is more than 20HP then a chain code of 50 or 428 roller chain should be used, These code specifications are mentioned in the following table.

Roller Width: Space between inner plates.
Pitch: Center to the center length between two pins.
Average tensile Strength (Lbs): Chain Codes, Pitch, Roller Width.

Chain Codes Pitch Roller Width Average tensile Strength (Lbs)
35 3/8″ 3/16″ 2,100
40 1/2″ 5/16″ 3700
41 1/2″ 1/4″ 2000
420 1/2″ 1/4″ 3700
428 1/2″ 5/16″ 4,200
50 5/8″ 5/16″ 6100

So, One of the Important questions we can ask ourselves is how to Identify our Drive chain. To answer this question I would like to show a picture and theoretical analysis of identifying our chain drives.

How to Identify Our Drive Chain

Measuring the pitch is the easiest way to tell them apart.

We want to define the pitch of the chain look at the first digit of the “chain size” in the roller chain, Pitch = (First digit x 1/8).

For example, the number 3 in the #35 chain tells us that the pitch is 3/8″ Similarly, 40, 41, and 420 have a pitch of 4/8″ and #50 have a 5/8″ pitch.

You can use any other tool from which you can measure the distance between the 2 teeth, one alternative to measuring the pitch can also be by using a wrench of 3/8” and 1/2”.

In order the tell the difference between chain codes 40 from 41 and 420, a measurement of the distance between the inner plates will do the trick.

Alas, order to differentiate between chain codes 41 and 420 can be done so by pin Diameter (41 chains have a slightly smaller pin diameter compared to 420 chains).

What is the Function of the Clutch and Torque Convertor in Go Karts?

The increase in rpm of an engine activates the medium to provide automatic transmission known as a clutch. However, the clutch should not be engaged when a Go kart is idle, the idle speed of an engine is around 1650 rpm.

Clutch can be evaluated on a number of factors like, build quality, material, type, and application. One thing to bear in mind is that they have a fixed gear ratio and will have an engagement range of 2000-2500 rpm.

Hence since there is a high engagement range so clutch go-karts are often used for racing purposes. They give a much snappier response and do well at a high torque range, much more noticeable at higher speeds.

But if you are considering a clutch for off-road go-karts. I might well ask you to reconsider the reason being, that off-road Go-karts have a tendency to experience low to medium torque ranges hence making the clutch an inefficient transmission and drastically reducing its time span with the additional problem of clutch slippage.

Related: Everything about go-kart transmission

So off roads are the place where torque convertor shines, consider torque convertor as a variable transmission connected to the side of the go-kart engine. They provide a variable gear ratio and can be considered ideal for low speeds, and inclined terrain.

Comparison Between Torque Convertor and Clutch

Each of the two transmissions has its own added advantages and depends on their nature of use. But there is a long drawn-out battle between go karts users in which transmission stands at the top between the torque convertor and clutch. In our showdown of a go-kart torque converter vs clutch, hence we will be analyzing both in the following table.

Torque Converter Clutch
System: Belt System: Chain
Gear Ratio: Variable Gear Ratio: Fixed
Efficiency: 80% Efficiency: <100%
Torque: Low end Torque: High End
Cost: Low to Medium Cost: Low (Single Disc)
Usage: Off-Roads Go Karts Usage: Racing Go Karts

Table: Torque Convertor and Clutch Comparison

No. Use Torque Convertor if: Use Clutch if:
1 You have an Off-Road Go Kart You have a Racing go Kart
2 You expect a lot of stops and go conditions You expect a lot of High speed
3 You have kids Driving the Go Kart You plan to race go-karts
4 You plan to drive it at low or medium speed You plan to Drive at High speed

Table: Uses of Torque Convertor & Clutch

How Much Horsepower Does a Go kart Need?

We need to look at a broader perspective of the world and there is no one particular answer, depending on the need of the user the amount of needed Horsepower can among Go karts, depending on the rider’s age, size of the cart, and whether its an indoor or outdoor model, usually from 4 to 16 horsepower.

Indoor Go Karts should be anywhere between 5Hp to 13Hp, and if you are a beginner a lower hp will help you adjust with speed acceleration.

Outdoor Go Karts such as professionals and Racing go-karts can have more than 20hp and can go really fast, considering Elevated terrain and muddy roads. Although most go-karts above 22 or 23 Hp aren’t allowed in many race courses.

Consider Your Go-Kart’s Weight for the Horsepower

For a rule of thumb, we can say that if a Go kart is heavier in weight, the higher should be the horsepower in order to compensate power-to-weight ratio, but there is a limit to how much horsepower you can have as you do not want to put a strain on your engine and a higher horsepower is not very helpful always.

So if you consider using an indoor track. I would advise leaning towards 10 to 13-horsepower go-karts. A 22HP Go karts are very rare and aren’t always beneficial in Racing due to added disadvantages like reducing engine life span and burning of tires.

Insightful Analysis Regarding Horsepower

So, to conclude my analysis I can say that an average Go kart has between 5 to 10HP, but professional Go karts that are meant for races can be one with higher Horsepower considering their need of use and the terrain they drive on and some can go even beyond 22Hp.

So the question to the answer that how much Horsepower is enough. It really depends on many factors and the need of use and according to that, any individual chose accordingly. But one should remember not to max out your Horsepower as it will reduce engine and transmission health and will burn out your tires more quickly.

My Recommendation for Go Karts Engine (Data-Driven Fact)

Tillotson 212cc Engine

Tillotson 212cc Go Kart Engine

I chose this engine because of its key features such as Hemi- portable and efficient design, 9+Hp Engine, Low weight to performance ratio, and High Torque.

It’s also very fuel efficient. Combined with a large fuel tank and a consumption rate of about a quarter gallon of fuel per hour (at half load). It can run for about many hours before it requires any refueling.

Lifan LF 168F-2BDQ Engine

Lifan LF 168F-2BDQ Go Kart Engine

I chose this engine because of its key features such as Automatic Shutdown Protection which adds Safety and protects the engine, 1600 Hour engine, Low weight performance ratio, Electric Ignition, and Fuel efficiency.

This Go-kart has a very durable and long-lasting engine and is one of its kind making it more efficient considering it is made up of cast-iron sleeves and automotive-grade parts.

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