Increasing the compression ratio of a naturally-aspirated engine increases its thermal efficiency. To avoid being deceived, you need to take the time to understand the effects of raising or lowering an engine’s compression ratio. The primary concern with higher compression ratios is the increased likelihood of detonation. The opposite occurs when the compression ratio is increased to 10.5- or 11.5-to-1. If you’re sending the archives to someone else, or you’re posting them online, you’ll probably want to use a format that the recipients can access with less fuss. Less fuel is required for each horsepower generated. First, we installed Bastion and compressed its folder — about 863 MB in size of music, graphics, executable files, and various different types of documents: Next, we compressed Hotline Miami, which is 654 MB of data: The winner by pure compression is 7z, which isn’t surprising to us. If you have an All-Motor setup, you can use the following chart to estimate the impacts of a compression ratio change. For compression ratios between 8.0-to-1 and 12.0:1, the higher compression ratio engine will make more power when the boost is between zero and 20psi. How to Change the Theme and Accent Color of Instagram DMs, How to Record Shows and Movies on YouTube TV, How to Get Cycling Navigation Directions in Apple Maps. We’ve included a chart showing the power change to be expected if you started with a 9.0-to-1 engine and you considered going up to a 10.0-to-1 or 11.0-to-1 engine or going down in compression to an 8.0-to-1 and 7.0-to-1 engine. If the means used to achieve this ultra-high compression ratio reduces the combustion efficiency (percentage of air-fuel mixture burned in the cylinder), a slightly lower compression ratio that doesn’t have this impact will be ideal. He's written about technology for nearly a decade and was a PCWorld columnist for two years. While the engine would be more fuel efficient with a higher compression ratio, a ¼-mile course without pit stops wouldn’t benefit. This reduction in volumetric efficiency is the result of having less unswept volume that could be filled. We will get into this in more detail later, but the important thing to remember is that increases in boost pressure reduce the ideal compression ratio. What you feed your engine has a direct effect on ideal compression ratio. We stuck with popular applications at their default compression settings to simplify things. For a drag application where you aren’t spending any time at low boost levels, a low compression ratio is more likely to be ideal. While the charts can help provide direction, nothing beats actual testing. Current IndyCar engines are good examples of high compression ratio, forced-induction engines. We’re happy with our overall results, but you might see different results when compressing different types of data. We’ve seen 7z come on the top of file compression benchmarks time and time again. Instead, these effects are rooted in science. There is also a slight reduction in exhaust energy with a higher compression ratio. If your application desires more power off-boost and up to about 20psi, raising the compression ratio should be considered if the fuel to be used has the knock-resistance required. Games incorporate graphics, music, text files, executables, and various other different types of files, so they’re a good real-world dataset with various different types of files. When looking at the impact to power output, one needs to adjust for the impact made by the change to the engine’s volumetric efficiency. 7z is the least supported — it’s not integrated into any operating system, so you’ll have to install an application to open .7z archives. How to Create and Manage To-Dos in WhatsApp Using Any.Do, © 2020 LifeSavvy Media. Nitrous Oxide? If you work with Mac or Linux, you could use a .tar format instead. Depending on the application, it may be. Setting up an engine to run E85 instead of pump gas expands the range of possible compression ratios that can be run. Since less energy is wasted to the cooling system, the amount of temperature increase in the cooling system during a full-throttle pull will be less on a higher-compression engine than one with a lower compression ratio. Unfortunately, being able to run a higher compression ratio doesn’t mean that is the ideal compression ratio. Long before forced-induction found its way onto factory engines, high-compression pistons were one of the original go-fast upgrades. By submitting your email, you agree to the Terms of Use and Privacy Policy. While everyone is familiar with the poor judgment that can result with a person consuming alcohol, few understand that allowing an engine to consume alcohol-based fuels also opens the door to some bad judgement. Compression ratio isn’t the only factor, of course. Here is something that may surprise you. The silver line represents the original compression ratio of 9.5-to-1. The lower compression engine will also make less power below the 20psi boost pressure mark. In racing series where reducing fuel consumption provides a competitive advantage, running a higher compression ratio that sacrifices some power at higher boost levels, but delivers better fuel economy, might be the way to go. WinZip also didn’t beat out the integrated Windows support for creating Zip files by that much. The boost levels that will be set will also factor into the ideal compression ratio. Since we launched in 2006, our articles have been read more than 1 billion times. All compression benchmarks are rough. But a 9.0:1 engine will make more power than an 11.0:1 engine from about 22psi to 30psi. Look on a forum, blog, Instagram or YouTube account and you can find a number of “engine builders” sharing their thoughts and feelings on the best compression ratio for a particular engine or application. If an engine is going to run on an exclusive diet of racing gas, compression ratios can be higher than pump gas. How-To Geek is where you turn when you want experts to explain technology. What is wrong with raising the compression ratio on an engine that runs ultra-boost levels? What Does “ITT” Mean, and How Do You Use It? Instagram Question | E85? Stay tuned. But, if you want the best compression ratio possible, 7z is the way to go. Compare and evaluate the two engines to see which delivers better results. The original OEM compression ratio of your engine is the ideal compression ratio for the engine. In addition to understanding the effects of raising or lowering an engine’s compression ratio, you also need to understand how fuel octane, alcohol percentages, type of fuel injection (port or direct), boost levels and types of driving will factor into selecting the ideal compression ratio for your application. Notice, the higher the compression ratio increase, the higher the performance gain at these low boost levels. In addition to understanding the effects of raising or lowering an engine’s compression ratio, you also need to understand how fuel octane, alcohol percentages, type of fuel injection (port or direct), boost levels and types of driving will factor into selecting the ideal compression ratio for your application.