Horsepower Review: Automatic vs. Standard Manual Transmissions

January 27, 2012

A simple horsepower review will reveal the facts regarding which kind of transmission is best for your car. It is common knowledge that cars equipped with an automatic transmission will get a lower horsepower rating and top speed, than a similar car equipped with a manual transmission. This is due to several factors such as design and weight, as cars equipped with an automatic transmission are marginally heavier than their manual counterparts.


Take the case of the 2010 Chevrolet Camaro SS. The automatic transmission model has 26 horsepower less than a manual equipped model. This is due to the fact that automatic transmissions work on the principles of pressure and resistance, which all have an effect on how an engine produces power. It is common knowledge that anything hydraulic in nature requires pressure to perform the specific function. If there is pressure, then resistance will ultimately follow.

Automatic transmissions rely on fluid pressure to properly engage or disengage the set of gears built in the system. The enormous amounts of pressure produce resistance on the engines flywheel, which in effect is connected to the torque converter of the automatic transmission. The torque converter is responsible for the pressure build up inside the transmission case. It is the resistance of the torque converter that bogs down the engine and giving a net loss of horsepower.


It is hard to fault the convenience that an automatic transmission may bring, especially with the advent of dual clutch technology as pioneered by Volkswagen AG. A dual clutch transmission offers the best of both worlds for the average driver, as it combines the fuel efficiency and performance of a manual with the convenience of an automatic, as there is still no clutch pedal to play with. Enthusiasts agree that DCT or dual clutch technology will pave the way for a new generation of automobiles. The TC-SST or twin clutch sport sequential shift transmission of the Mitsubishi Evolution X is lauded as one of best DCT transmissions in the business, and makes enthusiasts wonder on how a car so focused as the Evolution is now equipped with an automatic.

Horsepower Loss

It will all depend on how the manufacturers tune the specific vehicle. Emission laws are partly to blame for the blunt in engine pick up, as power plants are forced to comply with ever-changing laws and resolutions regarding clean air. It is safe to say that the older the car, the harder it is to tune and produce more horsepower if it is equipped with an automatic transmission. If the car is manufactured to be specifically equipped with an automatic transmission, then the manufacturer would have undergone ways on how to compensate the pressure and resistance that gives additional load to the engine.


Quick advancements in technology and engineering have given birth to the DCT, and is welcomed by manual and automatic fanatics alike. Cars such as the Audi R8, BMW M3 and Porsche 911 all have different versions of DCT and are all proving to be better, faster, more efficient and easier to use than their predecessors equipped with a manual (with the exemption of the Audi R8, of course.)

Related Questions and Answers

Are there any Fuel System Additives for Increasing Horsepower?

There are a number of fuel system additives marketed to increase a vehicle's horsepower. However, the claims of many of the products are disputed. In general, one shouldn't expect any fuel system additive to increase the horsepower in a vehicle. Although some fuel system additives may make the engine run more efficiently and cleaner, possibly maximizing its available power. Nevertheless, caution should be exercised with such products, as many experts agree that fuel system additives are the automotive equivalent of snake oil, and do not do what the companies promoted they claim they do.

If I Increase Engine Horsepower, will My MPG Go Down?

To increase engine horsepower, one increases the the amount of air and fuel used by the vehicle. Therefore, in most cases, increasing the engine's horsepower will negatively affect the cars MPG rating. The extent of the effect on fuel economy will depend on the amount of power added, as well as a number of other factors. Cars with low MPG ratings are generally cars that are very heavy or have very powerful engines. One could make additional changes to the vehicle when increasing the engine horsepower to offset any negative effects to its fuel economy.

What is the Most Popular Way for Adding Horsepower to a Car Engine?

There are a couple of popular ways of adding horsepower to a car engine. One method involves forced induction, which pushes more air through the engine, allowing it to produce more power. Two methods of forced induction are supercharging and turbocharging. Superchargers include their own compressor for adding air, while turbo systems rely upon exhaust gases. Horsepower gains of 10 to 20 percent or so are common with forced induction. Another popular way for adding horsepower is intensive engine modification. Such as increasing the engine's bore and stroke, which could increase its power output.

If I Improve Fuel Consumption, will that Lower the Engine Horsepower?

To improve fuel consumption does not necessarily mean one will also lower the engine's horsepower rating. Although reducing the horsepower will generally raise fuel economy, there are a number of ways to improve fuel consumption without affecting the engine's horsepower. For example, the EPA estimates that properly inflated tires could improve fuel consumption by 2-3%. This, of course, would have no impact on the car's engine horsepower rating. Other methods of improving fuel consumption without negatively affecting horsepower include adding an efficient air filter and driving more conservatively.

How are Motor Horsepower Ratings Calculated?

Motor horsepower ratings are calculated by machines known as dynanometers. These machines measure the engine's resistance and are able to compute the horsepower rating, as well as the torque rating. A dynanometer may measure the horsepower rating at the crank or at the drive wheels. When measured at the drive wheels, the horsepower rating tends to be lower, as some energy is lost through the transfer. Auto manufacturers generally perform these tests at the crank to determine a car's official horsepower rating. The amount of horsepower actually making it to the drive wheels tends to be a bit lower.

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