Relatively Simple & Less Expensive Options:
* Cold Air Intake: Replacing the restrictive factory air intake with a cold air intake system improves airflow to the engine, leading to a slight horsepower and torque increase. This is usually a relatively inexpensive modification.
* Performance Exhaust System: A less restrictive exhaust system (headers, cat-back exhaust, or a combination) will allow exhaust gases to escape more freely, improving engine breathing and potentially yielding a noticeable horsepower gain. This is more expensive than a cold air intake but still relatively affordable compared to other options. Check your local regulations for exhaust system legality.
* Tune/ECU Flash: A custom tune or reflash of the engine's computer (ECU) can optimize fuel delivery and ignition timing based on the other modifications you've made. This is crucial if you've added a cold air intake or exhaust system. This requires specialized equipment and knowledge and may necessitate a dyno tune for optimal results.
More Involved & Expensive Options:
* Performance Cam Shaft: A performance camshaft with more aggressive lift and duration will improve the engine's breathing and power output, but it's a more involved installation that may require other supporting modifications (springs, pushrods, etc.). This significantly alters the engine's characteristics and may reduce low-end torque.
* Headers: Long-tube headers significantly improve exhaust flow, but they're often expensive and can be challenging to install in some vehicles. They may also require other modifications like an O2 sensor extender.
* Cylinder Head Work: Porting and polishing the cylinder heads can improve airflow, but this is an advanced modification requiring specialized tools and expertise. It's a relatively expensive procedure.
* Forced Induction (Turbocharger or Supercharger): This is the most significant and expensive way to add horsepower. It involves adding a forced induction system to increase the amount of air going into the engine. This is a major undertaking requiring significant mechanical knowledge or professional installation and can put extra stress on engine components.
Important Considerations:
* Reliability: More aggressive modifications increase the strain on engine components. Regular maintenance is crucial, and some modifications might reduce engine longevity.
* Emissions: Some modifications might not comply with emission standards in your area. Check your local regulations before making any changes.
* Driveability: Significant horsepower gains can alter the car's driving characteristics. Some modifications might make the car harder to drive smoothly at low speeds.
* Cost: Always factor in the cost of parts, labor (if you're not doing the work yourself), and potentially dyno tuning.
Recommendation:
For a 1992 Cadillac DeVille, starting with a cold air intake and performance exhaust system (perhaps with a tune) is a relatively cost-effective way to achieve modest horsepower gains without major engine work. If you're aiming for substantial power increases, forced induction is the most effective but also the most expensive and complex route. It is strongly recommended to seek out the advice of experienced mechanics and Cadillac specialists before undertaking extensive modifications.
