THE DEVELOPMENT OF ENGINE TUNING

THE DEVELOPMENT OF ENGINE TUNING IN A NUTSHELL!

During the '80s and '90s many cars, particularly 'performance' cars were fitted with mechanical or electronic fuel injection instead of a carburettor. (Oh happy days!)

With electronic injection, such as Bosch LE Jetronic, tables or maps held the fuel and ignition timing values which varied in relation to throttle position, manifold depression (vacuum) and rpm, and these were programmed into read only memory chips (roms) built into the engine control unit (ecu). Enterprising tuners found that they could read the contents of the roms once they had unsoldered them from the printed circuit board (pcb).

Next, they identified the maps and experimented with new values, programmed a new chip and fitted it into to a socket (chip carrier) which they soldered in place of the original rom. The term 'chipping' was born! By altering the fuel and ignition maps significant gains in performance could be achieved, often with better fuel economy as well.

During the '90s, diesel and turbo diesel engines started to become popular as car engines. These early ones used mechanical injection with a conventional throttle cable operating the injection pump. If an ecu was installed it was very basic and used to control the injection timing, heater plugs, turbocharger (in some), immobiliser, radiator fan and from 1996, the exhaust gas recirculation system (egr). Certainly, remapping wasn't possible or relevant since the ecu had no control over the fuelling.

From about 1996, thanks to ever more stringent emissions requirements, a more precise method of fuel control was needed and so fully electronic diesel control was devised. (Called EDC by Bosch). This used a drive by wire system and in the majority of vehicles, a VP37, VP30 axial, rotary injection pump or a VP44 radial, rotary pump was used. However, in 1999 BMW installed their M47R engine with the first implementation of a common rail injection system in a passenger vehicle in Europe - they chose the Rover 75 and Mg ZT for this 'trial' (owning the MG-Rover at the time)

Engines with rotary pumps could have their ecus rechipped, but tuners realised that if the ecu could be updated via the diagnostic port by the dealer during routine servicing, then they too should be able to this. Once again British inventiveness reverse engineered the process and remapping was born. This was also found to be applicable to many common rail ecus and really took off from about 1999.

One of the big disadvantages of remapping - that of losing the remap if the dealer updates the ecu was overcome for many Ford vehicles by Superchips. They developed their Bluefin product which an owner plugs into the diagnostic socket and uploads the new map at the press of a button as often as they need to. They can also reverse the process and restore the ecu to standard. However, the Bluefin is coded to the vehicle's vin number and so is not transferable to another, though Superchips used to do a reduced price exchange option so you could use it on your new vehicle (provided it was a Ford).

Of course, some companies found that common rail engines were very amenable to being tuned by adjusting the fuel pressure by means of an external add-on module. The common rail tuning box was born! Now there are many makes on the market ranging in price from £99 (old analogue types) to £500+ (mutton dressed as lamb?). TUV approved ones are usually of European origin (TUV is the German equivalent of the British Standards Institute). TUV approval is irrelevant to us here in the UK but in Germany and some other countries, it is illegal to fit non TUV approved parts to any vehicle (e.g. German motorcyclists may not change their tyres for any make, type & size that is not specifically TUV approved for their bike) By the way, some companies claim their products are CE approved - what nonsense! CE is not an approvals scheme, it is mandatory for all products sold in the EU to carry the CE mark to signify compliance with the relevant standards.

This growth in plug-in tuning boxes did not impress the remapping companies one little bit, who now saw their monopoly broken. In the early days, the cost of these were comparable to a remap - circa £500 but inevitably competition has seen prices fall and this has brought down the cost of a remap to around £300 for many diesels with a few exceptions.

Unsurprisingly there are misguided owners who will still pay £500-600 for a tuning box or remap in the belief that they will be getting something out of the ordinary, but in reality there is only so much that can be achieved with either method.

To further irritate the remapping companies, many current ecus cannot be remapped via the diagnostic port. Either the ecu cannot be reprogrammed or the software needed is heavily protected by the manufacturers and reverse engineering it is guaranteed to result in litigation for copyright infringement. But necessity is the mother of invention so in-circuit programming has been developed. This allows the rom chip to be reprogrammed in-circuit - without having to be unsoldered, but does have the disadvantage that the ecu must be removed from the vehicle and opened (breaking any seal & hence voiding the warranty - the ecu's and possibly the vehicle's).

All motor vehicles are a compromise and there will always be owners who want to modify and customise their pride and joy, just as there will always be companies who will make this possible.

EBAY 'CHIP MODS'

Some school kids are selling a resistor or variable resistor that is connected to the engines coolant temperature sensor. This causes the engine to remain in cold running mode and can increase the amount of fuel injected. However, most modern engine, especially diesels do not respond well if at all and eventually the ecu will regard the altered signal as a faulty sensor. With petrol engines, bore washing leading to excessive wear can occur and the mpg will be adversely affected.

If you really believe a £7 device can give your engine 20bhp, you'll probably convince yourself it has if you fit one!