How can you increase horsepower on an engine through general modifications without modifying the internals of the engine?

Are there benefits or tradeoffs from doing so?

What kind of things could I modify?

  • Airfilter?

  • Intake tract?

  • Exhaust system?

  • Various ECU chips or an ECU replacement?

  • Rip out all the seats, spare tire and interior and throw them in a dumpster to lighten the car?

closed as too broad by vini_i, Zaid, Fred Wilson, Pᴀᴜʟsᴛᴇʀ2, Bob Cross Jan 9 '16 at 23:07

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    Without more specifics, this question is close to unanswerable. Some "bolt-ons" will destroy one engine while another will be much happier. The only trick to increasing the power to weight ratio that works for every car is to remove weight in the driver's seat. – Bob Cross Jan 9 '16 at 15:38
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    @BobCross - Awesome! So a Google Car has more horsepower?? :D – Pᴀᴜʟsᴛᴇʀ2 Jan 9 '16 at 17:07
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    I'm going on the Atkins Diet. It's cheaper than a programmable ECU but probably more expensive than a K&N free flow air filter. That should get me some pretty good horsepower :-) – DucatiKiller Jan 9 '16 at 20:16
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    Going on a diet means better power to weight ratio no matter what car you drive! I'd rather remap my engine personally... – Max Goodridge Jan 9 '16 at 20:19
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    Yes. We're happy to discuss really open ended topics like this in the chat. In the Q&A section, we're trying to pose questions that have a real answer. For example, if you were asking "Should I run 10+ PSI of boost on a 10:1 compression ratio engine?", we would say "probably not without doing a lot of extra work." – Bob Cross Jan 9 '16 at 23:09

Engine Remap

One way of increasing the power from your engine, depending on the car is to get your engine "remapped". This effectively means that your cars on-board computer (or ECU) has had its software changed and as a result the engine is told to produce more power.

It should also be noted that changing the software used by the car can also be referred to as chipping or flashing (the same as you might flash a new bios on a motherboard for your desktop computer).

Remaps come in stages. A stage 1 remap is only tempering the software in the car. Stage 2 may mean new exhaust system and/or other components. Here is an example of a stage 1 engine remap. You can enter your car in to that site if you'd like to see more specific details of the benefits of remapping your engine on your particular car.


  • More power (BHP)
  • A lot more power if your car has a turbo especially
  • More torque
  • Better engine efficiency (but not normally better fuel consumption due to the increase in power)
  • Often a sportier feel to the car


  • May be expensive
  • Other components may be built to cope with the extra power and torque unless they are also upgraded
  • You must notify your car insurance provider on most policies or you could risk not being covered in the event of an accident (at least in the UK)
  • It will void your warranty assuming you still have one (see note below)

Note: One interesting thing about that last point made was that a stage 1 remap normally consists of only a software change. What this means is that if you car to the official car dealership (with most manufacturers, I know this for a fact with VW) is that when you take it in for a standard service, your software changes will show up as an error and they will reset your software for you back to factory default as part of their service. This means that they have (accidentally) reinstated your warranty as there is now no evidence that you would have tempered with it to begin with!

Never service a car at the dealership unless you want to loose your remap!

Note: You may be surprised at the amount of car manufacturers that will reduce the power that an engine produces to improve fuel consumption as well as use that same engine on more of their cars. You can then make use of this extra power when you have your engine remapped.

Note: This is of course only applicable to engines that have an ECU of course.

Good source of images for a chip replacement.

  • One more con: this will likely void any warranty on the vehicle. Also, for more completeness, might want to add that this is often referred to as chipping or flashing the computer/ecu. Nice answer! – Lynn Crumbling Jan 9 '16 at 18:56
  • Thanks for reminding me about the warranty info! I have edited my answer to reflect your suggestions. – Max Goodridge Jan 9 '16 at 20:14

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