The more I wrote about ECU remapping in the Aberdeenshire area the more I found myself having to write using terms that may not be fully familiar to all readers. Hence this simplified explanations of some terms you may come across when our competitors try their best and confuse you with science (or engineering terms). If you come across the terms elsewhere simply come back here and see how we can help understand.
For those who have more general ECU questions, you can find them on the ECU Remapping FAQ page. This page relates principally to explaining terms such as Torque, Brake Horsepower and Newton Metres.
WHAT IS TORQUE?
Most people are aware of the tool torque wrench which we use to tighten bolts to a particular tightness setting. This enables us to be sure we have tightened it to the optimum amount of force without risking damage, for example, stripping the thread. If we try to tighten the bolt any harder the wrench will just turn in our hand.
The term Torque used in describing engine power is the force created by rotating parts. Whereas the term horsepower relates to how fast that torque is being created. We can actually calculate the horsepower by knowing the torque settings. If you are considering having us do an ECU remapping exercise on your vehicle, however, I would not worry too much about the torque figure UNLESS you know you are going to be carrying full capacity heavy loads or pulling a trailer.
If you are driving a very heavy van load or pulling a trailer then I would be looking to recommend a higher torque setting. From experience in our High-Performance Car Clinic in Ellon, I found that as we tuned cars to higher torque settings we were able to physically feel the higher power creating tightness in our chest and back of the neck when accelerating very fast.
There are several different measurements of Brake Horsepower. For example, you can take two identical engines have one of them tested in the USA and one tested in the UK (or any of the other European countries). The one in the USA will always be considerably higher than the UK measurement often by considerable amounts. American engine laboratories will be following the SAE system tests without the alternator, water pump, and other auxiliary components such as power steering pump, exhaust system, etc. The UK laboratories will be following the DIN standard which requires them all to be fitted just as they would be in your car.
If you are comparing figures for your own car and those published in American car magazines just remember you are looking at different statistics which cannot be reproduced in the UK test centres. It would be like measuring your waist in inches and then in centimetres one will always be a larger figure than the other.
The word brake refers to a device such as the Engine Dynamometer (older mechanics might still refer to the De Prony brake which was used for some years). The Dynamometer would be attached to the engines output shaft in order to measure the force needed to stop your engine rotating at a fixed speed.
You should note that measuring the power at the engine output will always be higher than that measured on the main chassis drive as power will always be lost in the clutch, gearbox and wheel shafts. However, despite that, it can give a really good indication for comparison purposes.
What about the Newton Metre?
You may see this term used in some power reports (often it will be simply referred to as the Nm or nm). This is, as the name implies, a force of one newton applied to a rod of one metre in length is applied at a ninety-degree angle. This is normally used as a measurement of force by the engine rotation being exerted on a fulcrum at the other end of the one-metre rod.
Don’t get this confused with the same term used to describe a unit of work or energy. The SI standards authority tries to discourage this usage preferring people to use the term “joule” instead but some people are just out of date.
We will, of course, add any other potentially confusing technical terms to this page as the need arises. This would normally come from you our customer asking what terms mean. Don’t be embarrassed we all have our own technical trade jargon I am sure I would not understand all the technical terminology you use every day in your job. So if you want to ask about any terms just get in touch using our contact page and we will get back to you.
Published by Scott Cheyne