Improvements

We have now replaced the originally tested static fuel regulator to a more advanced linear and adjustable fuelpressure regulator. This is a quite common stock replacement part that makes the work a lot easier. The regulator is adjusting the fuel pressure in relation to the vacuum readings of the air intake. This lovely device is taking care of most of the necessary engine alternations. The tweaking of the injector readings might still be useful to trim the engine performance but we believe the pressure regulator to be enough to make the engine run properly.

Initial modifications

This is a fairly straight forward text on the experiences that we have had concerning the use of ethanol as gasoline replacement. The experiments and conclusions are all referring to the VW waserboxer 2,1 L DJ engine, but most of the information and procedures are usable on other engines as well. The modifications and problems may however vary. We would also point out that this is not to be regarded as a manual for ethanol modification but rather a collection of notes on our experiences.

The wasserboxer 2,1L dj engine is a fairly easy engine to convert. The engine is build to run on premium gas. Therefor the compression ratio is as high as 10:1 where a modern standard catalyst car has a ratio of approximately 8:1. This means that the benefits of ethanol can be gained without further modifications of the cylinder heads. A ratio of 12-15:1 would give even better performance, but we have decided to settle for the std 10:1 to start with. This gives us the possibility to run the engine on std gasoline if we run out of ethanol.

The major mods are fairly simple. First of we changed the timing of the distributor so that it now is timed to 15`OD where the std setting for premium gas is 10´OD. This gives us a little more power, but more importantly it keeps the fuel consumption at a low level. The engine will still run on gasoline, but its recommended to reset the timing before running any longer runs on gas.

The next mod is a second pressure regulator that rises the fuel pressure from the std 2.4 bar to 3-3.5 bar (adjustable). The result is a richer air ethanol mixture that compensates for the lower amount of energy in ethanol. The pressure regulator is controlled by the turning of a knob, and can easily be set back to the std 2,4 bar pressure. This mod may cause some problems with leaking injectors and is also putting a little bit extra pressure on the rest of the fuel line. An extra effort has to be made to ensure that there is no leaking. Also be aware of the fire and explosion hazard.

Thereafter a controller was constructed to alter/tweak the values that the ecu reads from the engine temp and air intake detectors. The purpose of this is also to richen the mixture. The std engine runs on the theoretically optimal air / fuel ratio of 14/1 (usually known as lambda 1or stociosmatic mixture). The ethanol/air mixture will be 8-10/1. The mixture ratio is monitored by a lambda sond mounted in the exhaust pipe. The read outs from the sond is quite far from the values that one might be used to from a gasoline engine. This solution is a compromise, but the readings can function as a rough guide. The ideal solution would be to use a broad-band lamda but since these are way over our budget we settled for this solution.

The fuel line is rebuilt with hoses and gaskets that is ethanol resistant. A second gas filter is also mounted before the gasoline pump. The injectors is also slightly modified. The std fuel hoses may very well be resistant to ethanol, but this mod is simple to perform and can also prevent some of the trouble that the cleaning effects of ethanol may cause once you are up and running.

The truck is a fairly heavy vehicle, with very poor aerodynamics. The consumption of premium gas was 0.9 - 1.4 l / 10 km prior to the modification. The consumption of ethanol is slightly higher, approx 1.1-1.5 / 10km. The performance of the engine is slightly improved by the modifications. The std engine produces 110hp and the ethanol mod engine produces perhaps 10-15 hp more.

The engine is running well but can sometimes, especially during cold weather loose power while revving. This is probably due to to poor air / fuel mixture. The truck is also experiences difficulties to start when cold.

The engine can whit out alterations still be run shorter distances on premium gas, and with a few alterations of the engine settings (timing and fuel pressure) the engine can be run on gas whit out any restrictions. We also have a kit consisting of a extra fuel pump, filter and a set of injectors that is kept in the truck at all time. In case of an unexpected error we can fairly easy rebuild the whole fuel-line and run on regular gasoline. this can be done without any special equipment and can be done in approximately 2 hours.

The fuel pressure regulator is a std air pressure regulator that has been rebuilt to fit bolt on to the rest of the fuel line. The ecu tweak box consists of std electronic components that is both cheap and easy to find. The extra fuel line kit was found in a container, but may also be bought at a local scrapyard.

The total cost of the modifications is approximately 100 to 200 $