Here's an idea that's in current practice when seeking to optimize single cylinder output. Suppose you located a Lambda (oxygen) sensor in each primary pipe of an engine's header system, 8 to 10 inches downstream of the cylinder heads. As opposed to simply measuring exhaust gas temperatures which, by the way, can be misleading when trying to determine effective air/fuel ratios during combustion, these devices measure oxygen content in the exhaust. They are thus positioned to determine net air/fuel ratio during combustion. Early versions of such a system used CO (carbon monoxide) measuring devices with slower response times than current Lambda sensors. Unless you're blessed with an opportunity to use engine cycle analy-sis (ECA) or comparable in-cylinder pressure measurement methods, oxygen sensors are a worthwhile substitute.
Is this a useful tool? To be sure. For example, achieving equal runner-to-runner (or cylinder-to-cylinder) airflow equality in terms of quantity is only a step toward optimizing individual cylinder power. Even if the same amount of air (and fuel) is delivered to each cylinder, air/fuel mixture charge quality can result in variations in effective ratios at the time (and during) combustion. Individual cylinder spark timing variations can also become demons. By the analysis of post-combustion exhaust gas, you can more accurately determine the potential for optimized power per cylinder. In prior Enginology columns, we've discussed the importance of creating and maintaining good mixture homogeneity, effective fuel atomization and proper airflow quality. By the latter, we mean airflow that aids both fuel suspension and fuel atomization. All of these ingredients are necessary if you intend optimizing individual cylinder power.
If you need further evidence, here's a real-world example as shared by Dennis Wells (Wells Racing Engines), no stranger to readers of CT. According to Dennis, "We'd been burning the same piston in an alcohol engine and decided to check individual cylinder timing. We degreed the balancer and discovered the problem cylinder was getting two degrees more timing than the others. Especially in an alcohol motor pushing about 15:1 compression ratio, this much timing can cause problems, and it did. So, I got one of those distributor reluctors that you can bend and adjusted for the timing error. Then we decided to look into the intake manifold situation by installing O2 sensors in all the header pipes. In the process of making distribution mixes in the manifold, we discovered the problem cylinder (previously burning pistons) was also the leanest, so it's no wonder we were having burned piston problems. I'm a strong believer in tuning cylinders on an individual basis."
Once again, what's the point here? Essentially, we're discussing ways to evaluate upstream changes to intake paths, fuel routing, and spark timing to specific cylinders. I've also seen distributor cap plug wire terminals "modified" to either advance or retard spark timing, thus enhancing single cylinder output. At least for now, let's stop and turn to valve timing.
Can camshafts be "optimized" by incorporating multiple lobe designs and placement on a given shaft? Certainly. Has there been experimentation and validated results using this technique in the past? Same answer. What you may want to do is continue reading future issues of this magazine because there are projects and plans in the making that will likely include ways the general circle track populace can benefit from engine analyses and experimental ideas that might seem unobtainable to this audience. It remains an objective of CT to find, explore, and share ways so-called Saturday Night engines can be either built or modified. Including ways that identify and lead to the optimization of single cylinder power optimization is definitely on our list of upcoming topics . . . both in this column and elsewhere in the magazine. But for the time being, that's about as specific as we're able to be.