How Ignition Tuning Sparks Your Imagination

Ignition System 6 photos
Photo: MSD Ignition
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Without a solid spark your gasoline car will feel lazy, and your wallet will be empty. Optimizing your ignition is an easy and rewarding task that is not being taught to late model enthusiasts, so let’s learn what puts the fire in your cylinders.
Your car has at least one spark plug per cylinder. Modern engineering has yielded plugs that are rated to last 100,000 miles, but truth in advertising is a story for another day. That leads us to routine inspections. Every other oil change, I remove the first few plugs to examine them. Factors like heat, cheap gas, and piston rings make it hard for older plugs to fire. This most often manifests itself in an occasional misfire or stumble at idle. While a misfire isn’t too stressful while stopped, they can cause fatal damage in traffic.

Now is a great time to test your ignition coils. In the old days, a brave soul could touch the distributor cap to feel a few thousand volts and use the pain to determine a healthy spark. Trust me, it's easier to use a spark checker instead of biting your tongue. Before electronics, every car had one coil that was forced to do all the work. It was forced to charge and spark thousands of times per minute, and it took commands from breaker points. These tiny contacts were located inside a distributor, and they rode on a tiny cam that wore down over the years.

Aftermarket Ignition
Photo: Public Domain
As a truly analog device, your distributor attempted to fire each plug a few milliseconds before the piston reached the top of its travel. This delay (known as ignition retard) allows fuel to mix evenly, so it can make the most work. Although computers control these events now, your spark plugs are timed to fire using degrees of the engine’s rotation. This is why your spark plugs are set to fire at a predetermined number of degrees before top dead-center (BTDC).

Every production gasoline car can run on 87-octane. The computer senses cheap fuel and dials back your ignition timing. More expensive gas has a longer chain of hydrocarbons, so it burns slower. Race fuel burns very slowly, but unless your car is tuned for it you will be wasting money. Your car can make much more torque with a tuned ignition system.

Nowadays, the computer has the final say, but it was once done by sight and sound. Almost all gasoline cars before 1990 had distributors. They were driven by the cams and used to send spark to each plug. If your car was stumbling, a timing light was used to verify and correct the spark was not happening too soon (advanced) or too early (retarded). A timing light is the perfect tool to use. Hooking a light to one of your spark plug wires makes you a hit at EDM events. The strobing delay can be dialed in to match what should be happening so you can see it under the hood.

Aftermarket Ignition
Photo: Public Domain
If your car is old, you can manually adjust the distributor to account for changes in weather, fuel, and track conditions. Yes, you can limit maximum power by dialing back the ignition timing. Many automakers started doing this while the transmission is shifting. This offers a comfortable ride while allowing them to make their transmissions, motor mounts, and driveshafts much weaker. Known as “torque management”, this insidious table should be the first spot your tuner addresses. Next up, fill your tank with the best fuel you can get. Florida has 93 octanes made possible by blending 85% gas with 15% ethanol. This mix burns very slowly, allowing my cars to run an aggressive ignition tune.

It’s your job to make sure your car is making optimal power, and it starts with ignition. Find a friend with a laptop to record your timing around town and you can add a few degrees here and there. This is not for the novice, so it's best to let a tuner get you dialed in on 93. Every car can make a bit more, so like everything else in the tuning world, you will become addicted to making your ride more efficient.

Going too aggressive will cause stumbling and “pinging.” This is when hot fuel spontaneously combusts while it's waiting around on the spark plug to fire. Because it's random, these uncontrolled events tend to shatter pistons along with your weekend. That’s why your engine has knock sensors. These are the failsafe that commands a weak spark if they feel “pinging” or stumbling take place.

Toyota & Lexus default their engines to the 87-octane table, and it stays there making little power. Other brands recover more quickly, as Mercedes-AMG will punish you with a dozen warning lights until it feels premium fuel again. This is where your tuner can de-sensitize timing changes once you promise to never run discount gas. Your computer needs to learn who’s boss, so until then, the aftermarket has several ways for you to keep an eye on it. That’s a story for another day, so here’s to a Happy Thanksgiving from all of us!

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