UNDERSTANDING THE NUMBERS BEHIND COMPRESSION IGNITION
Diesel guys are numbers guys whether they know it or not. You’ll see the Big Three touting numbers in all their ad campaigns—best-in-class towing, most torque, highest horsepower. In a day of small-turbo economy cars, diesel numbers are almost always big. For many aftermarket enthusiasts, 500 rear-wheel horsepower and 1,000 lb-ft of torque are sort of the starting performance benchmarks. Whether you’re good at math or not, numbers infiltrate virtually every aspect of the diesel market—so let’s have a look at them! We promise to try and keep it basic.
Almost all the diesel engines we work with in the performance industry are large, but if there’s a displacement you can’t place (or if you’re talking to an old hot rod guy) you can mix liters and cubic inches by taking the size in cubic centimeters (5.9L for instance = 5,900cc) and dividing it by 16.38. This gives us 360.2 cubic inches. That means an 8.3L (8,300cc) is 506 cid, and a 1.9L TDI is a tiny 116 cubic inches. It may be off by a decimal place or two, but comparing cubic inches to cubic centimeters can be helpful in everything from calculating airflow to sizing turbos, since most American hot rod math is non-metric.