Nothing will have your engine running rough faster than the wrong choice of fuel injectors. Not only that, you risk ruining your engine altogether if you make the wrong decision. So it’s important to understand the factors you need to consider when deciding which fuel injectors are right for your setup.
Bigger is not always better
It’s easy to fall into the trap of thinking that bigger fuel injectors equal more power, but unless your engine is set up to deal with the extra fuel, you’ll be on a fast track to trouble. The excess fuel will flood the engine and it either won’t run at all, or will be running too rich. This can lead to fouled spark plugs and damage to the engine.
There is a whole range of things you can do to increase your fuel capacity to accommodate bigger fuel injectors but the main ones are:
- increasing the airflow – this can be done by installing a turbocharger or supercharger, or fitting a bigger throttle body
- installing a bigger exhaust
- remapping the computer
- fitting a bigger fuel pump
- adding an adjustable fuel pressure regulator.
Running too lean
At the other end of the scale is where you’ve modified the engine but the injectors aren’t delivering enough fuel to keep up. If you’ve added a turbo, a higher flowing fuel pump, a bigger exhaust and remapped your computer, you’re going to need bigger fuel injectors. Otherwise your car will be running too lean and you’ll have a situation where your it is sluggish and lacking in power at best, or at worst, you’ll burn out the pistons and destroy the motor.
Size does matter
Both of these scenarios highlight why it’s important to have the right-sized fuel injectors. The best place to start to work out the right fuel injector size for your needs is to get an understanding of how much horsepower you expect to achieve with your modifications. We recommend you enlist the aid of a reputable car tuner to determine this.
The other critical factors are:
- whether the car is turbocharged or supercharged, and
- whether you are using E85 or standard pump petrol.
We have a chart to help you check the correct injector size.