Introduction – The ultimate engine tuning guide

It’s a common hot-rodder saying that “All the power is made in the head”. Swapping in a high performance set of heads, with the right combustion chamber volume, proper cooling and oiling passages, properly sized, finished and flowed ports, positively shaped valve angles and lightweight valves, properly damped valve springs, and the correct lift, duration, and overlap camshafts can significantly alter the operating characteristics of the motor. You can turn a 5000 rpm truck motor into a 9000 rpm race engine simply by swapping in the right top end.

I remember back when I used to own a 2.2 liter Toyota Celica equipped with the 5sfe engine that a tuning shop in Texas used to offer a dyno-proven 40whp upgrade that consisted of a SteveM 185hp head and a fuel pressure regulator. Of course the head alone cost 2000 dollars as an upgrade and included everything from a milled surface to boost the compression ratio to a reshaped combustion chamber, to reshaped ports, to resized valves, to custom ground cams with a lot of R&D behind them. With such a huge jump in power output, the factory injectors would have been maxed out at full duty cycle and still running the motor lean, and the addition of the fuel pressure regulator was required to at least get the car to run safely (yet not at its peak potential without a full retune).

However, even though all the power is made in the head, all that power is enhanced and maintained by tuning!

When adding several bolt on performance upgrades to your engine, or even going with more advanced upgrades such as internal work or forced induction, then the amount of power gained by simply slapping on these parts without a re-tune is always going to be less, and sometimes even significantly less than what you would get if you tuned for your specific combination.

Performance upgrades change the shape of the power curve, ultimately changing the engine’s volumetric efficiency at different points in the rpm range. These changes are typically non linear and biased towards one rpm or another. For example, a header tuned for resonance at 7500 rpms will give a boost in power in the range from 6500 to 8500 rpms, requiring the mixture to be richened in that range to compensate for the added airflow. What happens on typical fuel injection systems is that the entire fuel curve is trimmed up or down to prevent any overly lean conditions. But even thought this kind of trim keeps things safe, if the range between 6500-8500 is now properly tuned, the entire range below 6500 is now overly rich due to the fuel trim and is sacrificing horsepower.

Tuning your engine management system for your modifications gives you the ability to tailor the fuel delivery, ignition timing and camshaft timing events to make the most amount of power out of your combination, and to maintain that power over a long period of time by keeping your motor safe and reliable.

A mastermind is a group of people who all are working towards the achievement of a specific goal. It’s a think-tank and center for activism.

What is most impressive about this tuning guide is that it was researched and prepared using the mastermind methodology. By taking directive, input, and contributions from some of the most renowned engine tuners worldwide, we are able to bring you a mega-guide that covers everything from full throttle performance to drivability, from dyno-time troubleshooting to preventive pre-tune checks.

I pose that this is the ultimate tuning guide… incorporating input from people who have experience with Japanese Imports, European Tourers, and American Muscle; people with experience in building all motor big blocks, nitrous injected drag vehicles, and turbocharged / supercharged pressure cookers; people that have been north of the 1000hp mark on their customer cars time and time again, people who have tuned-up cars to 4x times their factory horsepower, and people who are sought after so much so, that they have spent a significant portion of their careers as travel tuners, that travel from city to city, from one high power build to another, from one tuning session to another, working full time, as the tuning elite.

I have consulted with them, consolidated their input and created this unique guide. Their knowledge is now yours!

Tuning Goals

In this guide I will cover 6basic goals that you will tune towards, these goals are:

• A smooth start
• A clean idle
• A responsive motor with good throttle response
• A ‘lean cruise’ condition giving you best MPG even from a large displacement, gas thirsty motor.
• A ‘Power Enrichment’ zone for high demand conditions (full throttle and full boost).
• A safe ‘standing mile’ endurance run.

And for each of these tuning objectives I will cover the fuel, ignition, and cam tuning (as well as other methods of tuning and adjustment) that are required for that aspect of your engine’s performance.

Typically taking your car to a dyno operator or tuner only gets your setup tuned for power enrichment, which is great when you are at full throttle or in boost. However, having a complete tune for your motor will produce a car that is both faster, safer, cleaner, and more efficient in real world conditions in mid throttle, mid turn, mid traffic, during repetitive high speed passing on the highway or even just idling in your driveway. A complete tune by a tuning house is typically a very expensive proposition and so this guide gives you the information, concepts and tools necessary to pull this off on your own.

What you will also find in this guide is a lot of trouble shooting advice both on and off they dyno. The reason for this, as some of you may be aware, is that having faults in your ignition, electrical or fuel systems may significantly reduce power output. Sometimes it is possible to ‘tune around’ these problems (for example a weak fuel pump may cause a drop in fuel pressure causing a lean condition, adjusting the injector duty cycle upwards can correct for the leanness, however with time, the root cause of the problem which is the faulty fuel pump will continue to weaken, and the mixture will lean out again, possibly causing catastrophic engine failure)

You may be able to temporarily tune around a problem masking it’s symptoms but in the long run it is always best to fix the problem at the cause to maintain a setup that will be safe and reliable, not just today, but in the future as your components age. Since this guide is geared towards power AND reliability, you will find a lot of trouble shooting advice and pre-tuning pre-checks that must be satisfied in order to ensure that you are getting the best performance and safety out of your tune.

The bottom line:

No matter how much money you’ve spent on performance parts and products, if you haven’t tuned the car for your modifications, then you are definitely leaving power on the table. Furthermore, the more you have invested, the more you should tune … here is a simple example:

Figure 1 - A modified turbocharged Volvo gains over 60 wheel horsepower in just six dyno pulls by simply richening up the air fuel ratio! Think about that, 60 horsepower in under 1 hour and for probably less than 300 dollars. As far as horsepower per dollar goes, tuning can be a bargain….

Price: $26.99

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