bosch motronic tuning

[ever88]

hello folks

anyone attempted or know how to approach tuning of the boch motronic system on the 944.

I have contacted a friend of mine I have lost touch with whom fitted a mini supercharger to a 2 litre ford and runs 5 psi boost with only spark and fuel alterations. Just thinking a loud about perhaps something similar on the 2.5. I have now problems with fabrications and calculation of pulley size but are not certain on the fuel and spark alterations that would be required.

if anyone knows this would much appreciated.

thanks
Paul

 

[Hilux]

Standalone mappable ECU is the route I would take.

 

[Peter Empson]

Standalone is the ideal but pretty expensive. Personaly I went the cheaper route of a Vitesse piggyback. The only other safe option would be to find someone to map it for you on a rolling road and then burn you a custom chip, although based on a quote I had it wouldn't have worked out much cheaper than the Vitesse option which also has the benefit for more long term tweaking.

 

[Neil Haughey]

There was a software package called I believe DMEedit available awhile back that claimed to completely crack all the older DME chips. This would allow someone to look at all the curves, factors etc. etc. and change at will i.e. burn a new chip with the desired changes. However one has to bear in mind that this is only really usefull for unusual tune ups on these cars since off the shelf chips are available for so many levels of 951 tune for example.

 

[Hilux]

However one has to bear in mind that this is only really usefull for unusual tune ups on these cars since off the shelf chips are available for so many levels of 951 tune for example.

Not quite true. A truly mappable system is not like a pre programmed chip (PPC). A PPC takes certain parameters into account at certain stages. eg: it may well incrementally use for example every 200 rpm as benchmarks and then at those points build in specific parameters (wider than necessary) for fuelling and ignition advance etc as a PPC has to assume a greater range is needed for the many engines that will use it. A fully mappable ECU however allows almost infinite tweaking of YOUR engine at much finer increments so is truly customised to that engines characteristics.

 

[Neil Haughey]

Paul, one has to consider though if the cost is worthwhile if for example the state of all the other components is either stock or fits in with one of the known levels or packages. IMHO this is the case when considering either a solution that reverse engineers the DME or a standalone aftermarket EMS. True the standalone will give advantages you can't get from cracking the DME code. Personally something like DMEedit would be usefull for someone who is interested in setting up their own tuning company. For someone who only wants to tune their own cars it doesn't look like a good value for money route to take.

 

[Neil Haughey]

Forgot to add the following thought that ppl continually ignore with regard to dyno custom chip tuneups.

Do you drive your car on a road or on a chassis dyno?

Think about it. The OEM's spend a lot of time testing cars on real roads and collecting data which all goes into deciding the final program. One could take the approach of saying, ok I will tune for 98 octane fuel rather then the original 95 and remove some of the margins because I baby the engine when cold and service it all the time. Then you could drive around and collect loads of data which you then gradually use to refine your own program. This for me is the correct approach if you want to improve on what the manufacturer has given you within your own operational parameters. Trying to kill the motor on a balls out rolling road tuneup session is madness IMHO and I am amazed that anyone is brave enough and stupid enough these days to try this.