Spark Plugs by The Professor

We've all seen the marketing campaigns from spark plug manufacturers extolling the virtues of the latest and greatest plug design. One of the more notable developments in plug design that has been fruitful is the use of precious metal alloys for center electrodes. High melting point alloys such as platinum and iridium have enabled longer plug life in engines that are designed to run extremely lean mixtures, or in some high performance applications where combustion pressures and temperatures are extremely high due to turbo charging, supercharging, and/or nitrous oxide injection.

As I touched upon in my previous article titled "Getting a Better Spark", most modern production-based ignition systems are designed to provide a relatively weak spark over a fairly long duration. Regardless of the design of the particular ignition system, the spark plug's function is to ignite the air and fuel mixture in the combustion chamber. When the voltage delivered to the plug by the ignition system becomes sufficient to reach the ionization point of the fuel mixture in the combustion chamber, the current will ark across the plug gap to ground. The spark serves to ignite the mixture and create a flame front that rapidly disperses throughout the chamber as the combusting fuel and air mixture expands.

In modern engines running extremely lean mixtures, having relatively long spark duration is an engineering solution used to meet the ever more stringent clean air standards. These types of systems are also used to prevent rpm surge that can occur in some lean-burn fuel injected engines run at steady throttle. Conveniently enough, the use of such relatively low energy ignition systems is also due to cost considerations. The swirling mixture of air, with fewer fuel molecules available presents a mixture that is harder to ignite. Since the air and fuel mixture itself tends to provide a certain level of evaporative cooling to the combustion chamber, these leaner running engines tend to run higher combustion temperatures. In such applications, the higher thermal stress on the plug created the need for precious metal/high melting point electrodes such as platinum and iridium.

From a performance standpoint, plug manufacturers have tried to develop variations to long-standing designs in attempts to ignite the fuel and air mixtures more efficiently. Efforts have primarily focused on the center electrode and ground construction. Plug manufacturers have long ago realized that plug design is not a “one size fits all deal”. Today, plugs are purpose built, high quality products that can have a significant effect on an engine's performance. Many racing plugs, for example, will usually have a silver center electrode along with a shorter ground tang. This configuration allows more spark to be exposed to the incoming mixture as the spark is less obscured by the tang itself. For many years, tuners have indexed plugs by shimming them so that the gap would face towards the center of the cylinder or intake port; the theory behind this being that the flame front would ignite and move more rapidly throughout the chamber. In addition, racing spark plugs are not usually fitted with a resistor, and as mentioned, often utilize a silver center electrode. Remembering from last month's article, the use of silver in most performance applications is due to its superior electrical and thermal conductivity, enabling higher spark energy and rapid heat dissipation. Regardless of the design details of the particular spark plug, there are four main factors when choosing a plug for a particular application.

Heat range- This refers to the ability of the plug to dissipate heat. All spark plug manufacturers have their own system for identifying what the relative heat range of the plug is for a particular application. For a plug to work properly, it must maintain a certain amount of heat in order to burn off normal residues from the combustion process. Too hot a plug will lead to pre-ignition, as the plug stays hot enough to self ignite the incoming charge before the ignition system has had a chance to fire. Too cold a plug and the un-burnt residues from the combustion process will remain on the plug and lead to fouling. A properly selected plug having the correct heat range will have a light brown to gray/white color on the center electrode insulator without additional composite buildup elsewhere on the plug.

Plug reach/thread configuration- This refers to the size; thread pitch, and length of the threaded portion of the plug. Most plugs come in standard metric sizes and thread pitches such as 10mm, 12mm, and 14mm.The correct length of plug should position the threaded barrel end of the plug flush with the inside of the combustion chamber with the electrode portion protruding slightly into the chamber. Too short a reach and the shrouded plug will foul and/or short to ground. Too long a reach and the plug can overheat and possibly interfere with the valves and piston; moreover, any exposed threads of the plug will become sooty and can damage the cylinder threads upon removal.

Plug Construction and Materials- Plug manufacturers spend a lot of time and money developing plugs for specific engine applications. Factors such as cylinder pressure and fuel types play a big role in spark plug selection. Just because a plug may have the correct heat range and reach, it may not perform well in a particular application. Some competition engines running high cylinder head pressures or using difficult to ignite fuels like alcohol require plugs with special design considerations in order to maximize performance.

Ignition System Energy- The ability of any particular spark plug to work properly is dependant to a great extent on how much energy can be supplied to the plug. While there are many new plug designs available from various manufacturers today, not all will match up well with some ignition systems. For instance, some of the retracted ground electrode plug designs and/or electrode materials need significantly more energy to perform properly; this energy may not be available in certain ignition systems.

For most people the easiest way to ensure they're using the correct spark plug for a given application is to consult their owner's manual and/or their service provider. There are many of us however, that are driven by a desire to seek improvements in performance and/or fuel economy. We at Team Motorcyclist's Post have looked at some alternative spark plug designs from various manufacturers, and have found some that work better for our applications than others.

One company that has some very unique designs of performance spark plugs is Brisk. We came across this company and their products at the recent Performance Racing Industry Show in Indy. The European based company offers their Brisk Premium Spark Plugs that we have tried with some measure of success in our race motors. A new name to the U.S. market, Brisk USA is set to take on some of the world's largest spark plug manufacturers head to head. No small player themselves, Brisk is one of the largest suppliers of spark plugs in Europe. While offering high quality conventional style plugs for a wide variety of applications, Brisk also manufactures some interesting designs that I'll mention in reference to the accompanying illustrations.

While we have elected not to publish specific horsepower/torque gains from using these plugs in our race motors, I will say that we were pleasantly surprised by the results. Moreover, overall throttle response was improved over the plugs we have previously used. It's not that often that you can find noticeable improvements without significant investments in time and money.

Brisk currently offers several variations of retracted ground electrode plugs. Brisk Premium LGS Series plugs are noticeably different than conventional plugs in that there is not a typical ground tang. In these designs, the grounding mechanism is incorporated into the specially formed plug body. While there are several major plug manufacturers that make variations on this style, Brisk offers what I feel are the most unique and the smoothest flowing (I'm talking cylinder head gas flow here).

Brisk Premium ZC/ZS/TXS Series plugs go yet another step in a very unique design direction. Brisk has incorporated two "ground rings" built into the insulator tip portion of the plug; this is the porcelain part that protrudes from the plug barrel. In developing these plugs, Brisk has what they claim to be the worlds only plug that provides three simultaneous sparks per one ignition impulse. Brisk informed me that these plugs were originally developed in conjunction with BMW's efforts to solve steady-throttle surging problems in some of their motorcycles, notably their flat twins.

Note: BMW now uses a revised ignition system/plug arrangement that has two plugs per cylinder firing at slightly different intervals; this eliminates the problem while aiding efforts related to increased performance and emissions compliance.

Brisk states that some of these types of plugs may require more ignition system spark energy than a conventional plug, and therefore may not be appropriate for some applications without an ignition system upgrade.

Brisk offers some material and/or style variations of these plugs depending on what the particular application is. The company states that the general advantages include:

Spark occurs towards the very tip of the plug and is not obstructed by a conventional ground tang that can reduce ignition efficiency.

Because these plugs don't have the conventional ground tang, the working portion of the plug can be positioned slightly further into the combustion chamber, enabling more efficient combustion of the chamber's mixture.

Plugs are more thermally stable and resistant to damage caused by vibration; this was found to be a real problem in Formula One years ago, and not just with spark plugs.

A European magazine called BMW Moto recently conducted an independent test that compared the performance of several brands of retracted ground style plugs. The tests were run on one of the latest BMW flat twins using various plugs from Brisk and other manufacturers. The results of these tests showed that in this application, the Brisk plugs made measurably more power and torque of the plugs tested. Brisk states that in other tests performed on cars, measurable improvements in horsepower, torque, and even fuel economy has been discovered due to apparent improved combustion efficiency offered by their designs.

For those who are looking for performance enhancements, your spark plugs may be something you should look at, especially if you've been meaning to change them out anyways. While your particular application may not be able to support the use of some of the most advanced features I've discussed here, Brisk can likely offer you a suitable replacement in a high quality product. While street applications normally require no tuning changes, note that all-out performance applications may require some experimentation with ignition timing and jetting to achieve optimal results.

Brisk USA carries a complete line of high quality spark plugs for most applications. For more information, you can visit their website at www.briskusa.com, or call Martin Uhlir at 713-459-6977.

The Laminar Lip by Paul Jamiol

Just what exactly is a Laminar Lip? Sounds like a wrestling thing or maybe something you heard someone in work whispering about at the watercooler. Something they tried on their spouse the night before. I had never heard of it until after 35 years of riding, I decided to fit my bike with a windshield.

My first foray was with a handlebar mounted shield. I quickly learned about "buffeting" aka turbulence aka getting your head pounded to death by the turbulence created behind a windshield.

I checked the web and everyone's answer was to get lowers. So I did. It was somewhat better but still the buffeting was there. This past winter I mounted a larger fork-mounted windshield with accompanying lowers. At seventy miles per hour I was still getting "buffeted". Back to the web and and good ol' Google.

My search bought up the "Laminar Lip". I went to their site to investigate this thing. What I found was a funky piece of plastic that you attach to your windshield which supposedly would cure buffeting.

A call to Laminar got me in touch with owner and designer of the Lip, Andy Corcoran. Andy was an Air Force mechanic with some industrial design background. He designed the Lip for the sport-tourers back in the eighties. I told him I would like to do a review on his Lip for the Motorcyclist's Post. He was interested and said one would be coming my way shortly. True to his word I found one in my mailbox four days later.

Upon opening the box (extremely well packed), I found a clear piece of plastic, make that modified clear acrylic (in the shape of an airfoil. which it actually is), directions and stick-on 3M Dual Lock(TM) fasteners. Looking at it, I had my doubts that it would solve my problem but the idea looked interesting enough to try. That idea is to change the air flow of a motorcycle windshield and thus easing the wind and turbulence that slams the rider's face and helmet.

The Lip is designed to be attached to the upper part of the windshield. Each Laminar LIP is designed for a particular motorcycle model. Depending on your motorcycle and windshield, fastening could be screws or the 3M Dual Lock(TM) fasteners. Mounting methods do differ. If possible, existing windshield mounting screw locations might be used. In most cases, 3M Dual Lock(TM) or 3M VHB tape is used for attachment.

Placement takes a little time and I had to adjust it a few times to get it right. Once in place, this inverted airfoil has a space of about an inch between the Lip and the windshield. This forces the air up and stops the air pressure from buffeting the driver. If you use the Dual Lock, the directions say to let the adhesive dry for 24 hours. You'll be able to remove it from the Dual Lock to make adjustments to the height. It took me three rides to find the perfect spot. I  don't necessarily believe this would be always the case. The radius of my Rifle windshield was the culprit.

Ok, does it work as well as the testimonials say on their website? Actually it does and does so very nicely. I rode over 1,000 miles with the Lip on mild days, windy days and cold days. I rode with it at 85 mph with varying degrees of crosswinds and it never budged or vibrated and most importantly I never felt like my head was on the receiving end of a prize fight.

 

Riding with the Lip on your windshield created this nice little pocket of no turbulence that made the ride easier. There was no sucking the wind out of your lungs or all those other neat things that happen with windshield turbulence. I did not get a chance to ride with it in the rain. So I can't report on that. It did turn out to be the cure to my problem and I do recommend the Lip.

The only things (and they were minor) that I'd would have like to seen with the Lip would be better directions. Maybe with more illustrations. They give you silver stick-ons to cover the mounting locks. It's a nice touch but give me them without the company name on them. If it's a good product (and it is), I'll tell everyone who makes it. I'll pass on the forced advertising.

The Laminar Lip goes for $75.00 plus shipping. You can get it from Laminar LLC, 2612 Croddy Way, Unit E, Santa Ana, CA 92704, Phone 714-540-8006.

So boys and girls, if turbulence behind the windshield is a problem, the Laminar Lip is a great fix. Check them out at www.laminarlip.com
 

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