Spark Plugs
How would you like to be shut in a chamber with temperatures of up to 3000 C, splashed with petrol and given a 30,000 volt electric shock 25 times a second, and be subjected to pressures 50 times greater than normal atmosphere? No? - well that's what your spark plugs are subjected to! So if you want peak performance from your engine, make sure you fit suitable plugs.
Three main points to consider are:
- All modern engines are now fitted with 'resistor' type plugs and you are advised to stick with this type. The high energy bursts from plugs can cause interference to ICE, EFi and engine management systems if resistor plugs are not fitted.
- Plug heat range - many plug manufacturers produce a competition range which are usually 'harder' or 'colder' than the standard fitment. For mild road tuning it is best to stick with the factory recommended item but colder plugs will be necessary for seriously modified engines.
- Electrode gap - unless there is a known benefit for doing otherwise, we advise setting the gaps as recommended. Some uprated ignition systems can generate a spark across a wider gap which may improve combustion.
However, on high boost turbo engines a large plug gap may result in the spark being 'blown out' and for these engines a reduction in the gap is usually specified e.g. Cosworth types.
Ignition Leads
The sensitive electronic systems on modern cars need protecting from outside interference, so just like the plugs above, the leads must be able to suppress the high voltage bursts flowing through them.
Good quality carbon cored 8mm silicone leads are quite adequate for most mild tune applications but the carbon core will degrade and performance will drop off over a period of time (typically 2-3 years). High performance silicone leads (up to 10mm) with a ferromagnetic/glass fibre core will out perform and outlast their carbon cored cousins.
Distributors
Pre engine management cars rely on 'mechanical' distributors to adjust the ignition timing through the rev.range. Most highly modified high revving engines will require a different advance curve to the standard distributor to achieve peak power. The usual requirement is for more ignition advance at low engine speeds and slightly less total advance which would typically occur between 2,500 - 3,000 rpm. DIY alterations to standard distributors can be quite successful but also time consuming - you rarely get it right first time. Also, if it is badly worn it should be replaced, in which case you might as well buy one already modified for you!
Ignition Systems
Up until the early eighties most European cars still had the now redundant 'contact points' system, with all its inherent problems (burnt contacts, points bounce at high rpm, etc.).
Early 'Electronic' conversion systems were either very unreliable, expensive or both. But as technology progressed and performance improved, all major car manufacturers had their engines 'factory fitted' with various 'contactless' ignition systems. Engine efficiency can be greatly improved by fitting an electronic ignition kit to an existing points type distributor. Once fitted these systems are maintenance free and can operate at engine speeds far in excess of the very best contact points system. The two main types of electronic ignition are 'inductive' and 'constant energy', the latter being the type most commonly used by car manufacturers.
Engine Management Systems & Controls
Due to the plethora and sophistication of the engine management control units (ECU's), sensors and controls now being fitted to all modern vehicles, it is not possible to cover this subject here. Some high quality, fully programmable, aftermarket management systems for controlling ignition timing, fueling, etc. are available and we invite your individual requests for information.
