As you pack more air and fuel into the cylinders, you significantly increase the cylinder pressure and the charge motion within the cylinder prior to ignition. This can make it less likely for the spark to occur with enough energy for combustion, or to occur at all. Even for a mild-performance car, minor upgrading of the ignition system can result in better starting, throttle response, performance, and fuel mileage. This is mainly due to normal wear over time, which results in higher resistance in the spark plug wires, a larger gap at the plugs themselves, wear at the distributor cap and rotor, and, if you’re still using them, the breaker points. All of these components are easy enough and relatively inexpensive to replace, but breaker points do not belong on high-performance cars.
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If your vehicle has breaker points and you want to get away from them you can install an ignitor conversion kit, such as one from PerTronix. They use a magnetic pickup with associated electronics to replace the points. You no longer have to be concerned with their periodic wear and need for adjustment or replacement. The kit installs discreetly inside your stock distributor; the only evidence of it is the two external wires instead of the usual one. The ignitor provides maintenance-free performance superior to that of points due to the increased spark energy levels resulting from longer dwell times allowed by the electronics.
When combined with a compatible coil, better plug wires, and better spark plugs the strength, consistency, and reliability of the ignition system is greatly improved.
Spark plug choice is critical because it can yield the greatest benefit. A plug that’s too cold can get fouled with deposits and cause misfires. A plug that’s too hot can cause detonation and engine damage. For most high-performance street and streetable track cars a standard-style plug of the correct heat range is fine. Plugs with iridium-center electrodes outlast and outperform conventional plugs. Manufacturers such as Autolite market less-expensive iridium plugs but they lack some of the features found on those by NGK and Denso.
The thin iridium-center electrode coupled with a tapered ground strap creates optimal conditions for ignition. These provide an open area that allows the flame front to propagate rapidly; smaller electrodes reduce the voltage requirement for the spark. Iridium plugs last significantly longer than regular or even platinum-tip plugs for not much more cost than the latter.
Enthusiasts often avoid platinum-tip plugs because they tend to not remove the heat as quickly as even a copper-core regular plug. Their purpose is long life, not performance. A properly gapped iridium plug can last up to 100,000 miles on the street, especially with ignition upgrades.
Improvements made for daily drivers also apply to high-performance street cars. However, the higher cylinder pressures associated with the higher power levels of the latter likely require the use of an ignition amplifier box along with a compatible, even higher-output, coil.
Amplifiers greatly increase the total spark energy and the duration of the spark for more complete combustion. The longer spark duration is the result of firing multiple sparks instead of just one. This provides additional opportunities for combustion to occur (or reoccur) because the chances of an ignitable mixture being near the spark plug at the time the spark occurs are increased. These devices usually require hardwiring larger-gauge wires directly to the battery to supply extra current for their faster-acting electronics to build more and hotter sparks in the time available. Amplifiers generally intercept the ignition trigger signal, amplify and/or multiply it, and then send a higher-voltage signal to the ignition coil to increase the voltage and the total spark energy. The coil must be compatible with the box to work best.
It’s also probably beneficial to replace your distributor with a superior aftermarket unit. They have morerobust construction and materials with tighter manufacturing tolerances compared to a stock unit. The absence of the accumulated wear of the older unit virtually eliminates excessive spark scatter and timing errors, which plague the stock distributor, especially over longer periods of time.
If you’re using an EEC-IV control system for ignition and fuel control you can gain some performance by also upgrading the TFI ignition module attached to the distributor. The stock modules have a tendency to overheat and cause the car to run roughly or even shut off until they cool down. In some cases they fail altogether and the engine doesn’t run. Aftermarket TFI modules are designed to not have this issue plus they also have upgraded electronics, which produce more spark energy.
For the streetable track-day car there are further upgrades to consider. These include an even hotter ignition box and coil along with an even more sophisticated distributor that allows for the use of different timing curves (on carbureted applications). The matched High Energy components from Crane Cams are an excellent example of race-quality products that are also completely at home on the street. The adjustable timing curve feature, in fact, allows you to use different curves for street and track use, thus providing better performance for each instance than would a single, compromised curve.
Eliminate the Distributor
One upgrade that can be beneficial in many cases is to eliminate the distributor altogether. CompuTronix has developed a retrofit distributorless ignition system based on the technology used on many later model OEM vehicles.
The distributor is replaced by an electronics module, which provides signals to two coil packs that use the “waste spark” method to fire the spark plugs twice as often as usual. This eliminates the need for a distributor, cap, and rotor, thus also eliminating the rotor/cap air gap. This greatly improves the accuracy of the spark timing, especially at much higher RPM where its very fast electronics allow it to maintain virtually full output across the entire RPM range. Not having air gaps in the distributor, etc., which slow down and weaken the spark current, is a big factor.
Having a total of four 60,000-volt coils at your disposal is another plus. Because there are more coils each has more time to fire, even after the wasted spark is considered. There’s enough time, in fact, to maintain full output up to 12,000 rpm should you need to go so high. Compu-Tronix claims this allows the DIS8 to provide more total spark energy than any single-coil system with a distributor.
The synch module and coil packs are sealed from the elements and use OEM-type Weathertite electrical connectors for a good seal without corrosion. This is an excellent option for a high-performance street car where a lot of spark energy and limited tunability is needed in a reasonably priced, maintenance-free system.
Of course you can take this distributorless concept even further by using a coil-per-plug setup and eliminating the waste spark to get the best of all worlds. This is now being used on most production vehicles, not only for performance reasons but also for better fuel economy and lower emissions. It’s designed into the powertrain control module and provides incredible timing accuracy, spark energy, and durability in new vehicles.
High-Resolution Crank Trigger
The ultimate system uses a high-resolution crank trigger for the best timing accuracy and consistency. Retrofitting such a system to an older car, although not impossible, is complicated. In very simple terms you need sensor inputs you don’t have, very fast electronics for each cylinder, and a control module to use all of this properly. Making it compatible and functional isn’t easy; making it work well is even harder. The cost, effort, and expertise involved are much greater than the potential benefit for most street cars.
The much-higher power levels and the likely use of a power adder on a streetable track-day car may make it necessary to use a colder-range spark plug. It may also be beneficial to use a spark plug designed to better cope with such extreme use.
For example, multiple ground straps help ensure reliable ignition. ZEX racing plugs have a larger primary ground strap (with a copper core) surrounded by three smaller ground straps. This design helps ensure a spark remains possible even when very high cylinder pressures and charge motion velocities are encountered. This also adds a degree of redundancy and safety so that engine damage and/or injury may be prevented should there be a problem with the primary ground strap.
Other spark plugs with multiple electrodes are usually not meant for high-performance or racing use because their designs tend to shroud the spark too much and they use platinum electrodes. Platinum is fine for long life in a stock engine but it tends to melt more easily, especially with power adders.
A strong starting system is necessary when the compression ratio has been significantly raised and when a lot of spark advance is being used, particularly at warmer ambient temperatures. In addition to the function of starting the car the battery also serves as somewhat of a dampener for the electrical system, which can help to minimize large voltage excursions that can affect the ignition or other electrical/electronic systems. EFI systems must have a stable voltage level to function optimally even though they can still work at fairly low levels due to their voltage compensation capability.
Conventional batteries are fine for normal use but a better solution is absorbent glass mat (AGM) batteries. They are more resistant to vibration, heat, and similar issues, which can kill a regular battery. They’re more “power dense” so they can be lighter and/or more powerful for a given application. Best of all, they’re essentially maintenance-free and virtually spill-proof so they can be mounted in almost any position.
A daily driver benefits from a battery upgrade not only in terms of more reliable starting but also in the ability to run accessories, such as the audio system, with less fear of running the battery down too far. Optima’s family of batteries are a great solution because they are readily available and reasonably priced while also providing very high coldcranking and reserve power levels.
The RedTop battery is optimized for higher cranking power in a smaller, lighter package.
Optima also offers the YellowTop line, which still has very high cranking power but trades some of it off to achieve significantly higher reserve power levels. This is basically how long you can run on the battery with the engine off. If you have very high-drain accessories, such as audio and video equipment, this may be more of a priority to you.
Enersys Odyssey Batteries
The above also applies to the high-performance street car plus it likely has the additional burden of a higher compression ratio. Enersys Odyssey batteries are extremely compact for their capacity. They share the ability to provide very high cranking and reserve power levels, thus making them very well suited to remote mounting. Because they are a sealed gel cell/AGM construction they can also be mounted in virtually any position with no risk of leakage.
Odyssey claims their batteries have a design life between 8 and 12 years with a normal service life between 3 and 10 years depending on the application. This compares to 5 years and 1 to 5 years for a conventional battery. Even though these batteries may cost a bit more up-front they can be less expensive over time because they don’t need to be replaced as often.
Furthermore, Odyssey batteries hold their charge much better, allowing up to two years in storage before needing to be recharged (versus only 6 to 12 weeks for conventional batteries).
A final benefit is that when an Odyssey battery finally begins to fail it does so gradually so it is less likely to leave you stranded.
A streetable track-day car has little, if any, need for reserve capacity to run accessories with the engine off. It needs maximum cranking power with minimal size and weight. For such applications and where cost is less of a consideration a lithium ion formulation likely fits the bill, at least at the track. It probably isn’t the ideal choice even for minimal street use, especially in colder climates. For the ultimate lightweight battery a carbon-fiberencased lithium ion battery such as one from Lithionics Battery may be what you’re looking for.
Lithium ion batteries have several advantages over conventional lead acid and AGM batteries. For a given cranking power rating they usually weigh about half. They also last much longer; sometimes they’re able to endure up to 10 times as many recharging cycles. They’re also a completely sealed, no-maintenance design and hold their charge very well in storage. They usually can retain about 75 percent of their initial charge after one year.
Lithionics products have other unique features such as NeverDie and dual-voltage capability. Because all lithium ion batteries require internal electronics to ensure proper charging and safety, Lithionics has also programmed in a special feature that monitors the draw of the battery and puts it into a special sleep mode if you leave the headlights on, etc. It ensures at least 20 percent of the battery capacity is retained to allow starting the vehicle under all conditions. You simply push the NeverDie button on the battery and you’re ready to go. You don’t need to worry about being stranded by a dead battery.
The dual-voltage feature is very useful for extremely hard-to-start engines because it provides an additional connecting lug just for the starter circuit with a 16v output to provide more effective starting power. A normal 12v (12.8v, actually, with lithium ion) is also provided for everything else. The higher voltage per cell (3.2 versus 2v) allows for faster recharge times (two to four times) and much less voltage “sag” (the amount the voltage drops under load) on start-up. This prevents damage to vehicle electronics during start-up and also ensures more stable/consistent performance, especially with more sensitive EFI systems.
A high-torque starter motor can offset weight by potentially allowing a smaller and lighter battery to be used while still retaining sufficient starting capability. Reserve capacity, however, is lower but recharging time is much quicker.
If you consider a starter upgrade you should also consider an indexing high-torque starter, such as those from Powermaster, to gain clearance with headers and nearby parts while also reducing weight.
Written by Frank Bohanan and Posted with Permission of CarTechBooks