Naturally aspirated engines are ones that don’t have turbo or superchargers, which are considered forced induction. Unfortunately, increasing horsepower and performance on NA (naturally aspirated) engines is a bit more challenging than on engines that come from the factory with a turbo or supercharger. With that being said, there are a number of good performance upgrades that can provide solid power gains to any NA engine.
This guide is going to cover the best upgrades and mods for NA engines. This is most relevant for trucks, American muscle, and JDM cars that are more performance oriented, but these are applicable to just about any engine out there.
NA Engine Mods for More Horsepower
- Exhaust Headers
- Cold Air Intake
- ECU Tuners
- Camshaft Upgrades
- Forced Induction
1) Exhaust Headers
When most people think about exhaust upgrades they think about a cat-back exhaust system. However, the best exhaust upgrade horsepower gains come from the headers rather than the tail-end of the exhaust. You’ll get a deeper exhaust note without a super aggressive increase in noise in addition to solid power gains.
Upgraded headers improves exhaust scavenging and reduces backpressure which result in increased performance. Headers typically provide anywhere from 10-30hp gains depending on the vehicle, whether you choose long-tube or short-tube headers, and go high-flow or catless.
Overall, this is the best exhaust upgrade on any naturally aspirated vehicle and usually provides the biggest bolt-on power gains out of any other mod.
2) Cold Air Intake
An upgraded intake system usually isn’t a huge power provider, but it is a worthwhile mod if you are searching for some extra power. Additionally, an intake will give better throttle response and provide some cool engine sounds.
The purpose of a cold air intake on an NA vehicle is 1) to increase airflow, and 2) to reduce intake air temps. The first is achieved by increasing the size of the air filter and piping and removing any restriction in the factory design. The second is achieved by relocating the air filter to a different part of the engine bay where it can draw it colder ambient air, resulting in lower intake air temps which also helps power gains.
Some intakes will yield 0hp while others can provide 10-15hp. It really depends on your engine and what other mods you have. Nonetheless, the power gains might be small but it is a simple upgrade than can yield some worthwhile results.
3) ECU Tuning
ECU tuning is probably the best mod for any NA engine. If not, it’s right behind headers. Tuners, chips, etc. provide power gains by connecting to the ECU and altering the factory tune. Various parameters like air to fuel ratios, timing, and so on are altered to increase performance. Tuners also usually have various different maps available for power, fuel economy, towing, and so on which makes them helpful and valuable for multiple purposes.
Power gains from tuners really depend on what existing mods you have and how tuner-friendly your engine is. Generally speaking, the more mods you have the more valuable/the better power gains you get from a tune. In general, you can expect to see power gains from 10-50hp+ depending on your engine and mods.
Custom tuning will always yield the best results. However, using off the shelf tunes will suffice until you have all your other mods done – otherwise you might have to get your car re-tuned if you go to the custom route and add more mods down the road.
4) Camshaft Upgrades
Camshaft upgrades are probably the most advanced mod on this list. This is really reserved for the American muscle cars and trucks. While you can upgrade the cams on just about anything, platforms like GM’s LS engines tend to be the biggest candidates for cam upgrades. For example, an LS3 camshaft upgrade can provide 88hp. While it might be LS3 specific, that article is a good piece for explaining the benefits of cam upgrades and all the considerations that go into picking the right setup.
Cams control the opening and closing of the intake and exhaust valves. Upgraded cams allow you to control valve lift and duration, each of which can have big impact on performance. We’ll save the technical details for later as cams are a very complex upgrade and there are a ton of other mods and considerations that go into this upgrade.
Depending on how aggressive of a cam setup you go, cams can result in power gains from 25hp upwards of 100hp+. Again, these are an advanced mod but one of the best way to get big horsepower gains out of NA engines.
5) Forced Induction
Chasing power on NA engines can get really expensive. Headers, intake, tuner, exhaust, throttle bodies, and so on and you can easily be $5k+ into performance mods to only gain 30-40hp. Therefore, if you want big power gains one of the best routes to look is turbochargers and superchargers.
Superchargers tend to be more popular for the large V8 American powertrains where turbos are more responsive to the JDM/tuner market. With that being said, both of these options are the best route to go if you are looking for 100hp+ gains. Power gains really depend on the setup, but this is really the only place to look if you want the big gains.
NA Horsepower Upgrades Summary
Naturally aspirated engines are all unique. The best mods truly vary from platform to platform, but generally speaking headers, tuners, intakes, cams, and forced induction are going to be the big players in NA performance gains. The first three are pretty simple bolt-ons whereas forced inductions and cam upgrades are a lot more advanced and will require a lot of researching and time to determine the best setup for your goals.