When you’re increasing the power output of a fuel injected engine, one of the things you’ll want to know is whether or not the current injectors still have the capacity to supply enough fuel. There are plenty of upgrades available, but knowing which ones you need is key to getting the performance you’ve built in.

Accel has released a new instructional video on this topic and we’re pleased to present it below. The same information is contained in their catalog, which can be downloaded from their web site, but often it helps to have someone walk you through it first.

You’ll hear mention of a couple of terms that you may or may not be familiar with. One is Brake Specific Fuel Consumption. This is a number that most people use estimates for and those values are provided in the catalog. Specific values can often be found by using an engine dyno, unless you’re already there, use the estimates.

A second term that may not be familiar is duty cycle, which is really nothing more than the per cent time that the fuel injector is open. There are good reasons for not maxing out the duty cycle, so Accel recommends a value of 80 to 85 percent.

Everything else in the video is pretty straightforward, so have a look and work through an example yourself. If you download the catalog here, head over to page 188 for all the details. After that, sizing fuel injectors correctly will no longer be a mystery.