Engine Management - Tuning For Maximum Power

Now, I know the title of this post is sort of stating the obvious.

When you tune any programmable engine management system, you are generally trying to get the maximum amount of power that your engine will deliver.

But, this is only one of several very important aspects to engine management tuning. And unless you get all of the aspects right, you will not end up with the best tuning result possible. In fact, if you are tuning for a customer, you might get more power than the customer has every had before, but you still may end up with an unhappy customer, rather than a raving fan of yours who will tell their friends how great you tuned his or her engine.

So, at this point, we won't go into the obvious "maximum power" part of tuning.

We will though, go into the far more complicated and artistic areas of tuning for lowest fuel consumption, cruise, and tuning for a stable idle.

Lowest fuel consumption:

Let's say you are dyno tuning a vehicle that will be driven at less than full throttle for some of its working life. If this is the case, it's important for the engine of that vehicle to be tuned correctly at part throttle and cruise situations.

And this is a very important point. It is by no means only the amount of fuel you are delivering that determines the fuel consumption of the engine. While you are one the dyno, you should tune both injection time and ignition timing to achieve maximum power and torque under light throttle and cruise conditions.

I've seen situations on the dyno, where at cruising speed and throttle position, we have been able to double the horse power at the wheels by tuning the ignition timing. We are talking about going from a number like 9HP to 18HP. Which might not seem like much. But in terms of reducing fuel consumption, it is a big deal.

Idle Stability:

One of the more difficult areas of tuning (especially with engines running big cams, etc), is getting the idle to be nice and stable.

Many people try to have the Idle Speed Control system stabilize the engine idle. But in most cases this does not work, and the engine hunts up and down with the Idle Speed Control chasing after the engine speed.

The very first thing you need to do is to turn off the Idle Speed Control system so that it is not tracking after the engine. Try to have enough air coming into the engine so that the engine will idle near to the idle RPM you require.

Now, here is the important part...

What you want to achieve is essentially a "torque ramp" that increases both, as the engine speed drops below the required idle RPM.

So, as the engine slows down, the natural torque ramp you have programmed into your map will increase the torque of the engine and "hold" it from slowing down any further.

How do we do this?

We set the amount of fuel and ignition timing at the exact idle point to be just under what the engine actually wants.

For example, if the engine truly wants 2.3mS and 9 degrees of ignition timing, we give it 2.1mS and 7 degrees of timing.

Then, at the next RPM point below the engine idle speed, we give the engine 2.4mS and 11 degrees of ignition timing.

NOTE: Don't go too steep on the torque ramp, as that in itself will cause the engine to cycle up and down the torque ramp.

But, get this right, and you will have a far more stable engine than you could ever have if you had the same fuel and ignition numbers all around the idle RPM.


And, once you have that sorted, you can turn on your Idle Speed Control system again, and it will help out when the A/C turns on, or for other engine loads, and when the engine is cold.

Follow the above system, and the engine management system you are tuning will give its owner a lot more joy than one where the engine feels like it is going to stall, or cycles up and down at idle.

Now you have maximum power, great fuel economy, and a car that is truly nice to drive.

Engine Management - It's more than EFI

Some people put fuel injection and engine management into the same basket.

In many ways, engine management is so much more than just fuel injection. And, in fact, most ECU's that are called fuel injection systems actually do a lot more than just control fuel and spark delivery to the engine.

So then, let's agree to put them in the same basket for the purpose of this post. And, we'll call them Engine Management, just so it's easy for us all to understand.

Now, what is engine management?

Firstly, it's a device, normally called an Electronic Control Unit (ECU) or one of may other names, depending one who the manufacturer is, and what vehicle it is going into. We'll call it the ECU.

The ECU's primary function is to control the fuel and ignition delivery. There is pretty much nothing as important for the ECU to do on the vehicle. For if the engine does not run correctly, it doesn't matter if the ECU is controlling the suspension ride height based on road-speed, or if it is controlling the automatic transmission shift points brilliantly if the engine coughs and splutters when you put your foot down.

How does the ECU maintain correct engine control?

The ECU uses sensors to measure the amount of air going into the engine, the engine speed, engine temperature, air temperature, the exhaust oxygen content, and the throttle position (plus often several other sensors outside the scope of this post) to determine using tables and mathematical calculations to determine when to fire the sparkplugs, and exactly how much fuel to inject.

These calculations happen many times for every engine revolution, so the ECU is always up to date with the current engine conditions.

What else can an Engine Management System do?

The ECU can control things like, the fuel pump, thermofan, A/C or climate control, engine check light, and other relatively simple tasks.

But this is where is gets interesting. You can use an aftermarket engine management system to control your electronically controlled automatic transmission, your air suspension so it automatically lowers down at certain road speeds and then raises up again when you slow down (so you can clear driveways and gutters), your active exhaust system, so the exhaust only opens up above a user set road-speed and/or throttle position.

I could go on, but I think you get the point.

Programmable engine management is so much more than just fuel and spark, and you should ensure that the engine management system you choose is capable of controlling as many items and accessories on your vehicle that you would like it to.

This will save you adding additional boxes (that may have trouble working together) into your car.

With some planning, you can end up with the correct programmable engine management system for your vehicle, and having it control all of the functions you require.