Skoda Rally Blog

Alas I am back to work this week, so the work on the car can only happen in the evenings.  However, the upside is that (at present) the main work needed is to sort out the mapping, which doesn’t involve being under the car or anywhere else, it involves driving it and running it in.

The last drive resulted in a fair bit of data which with some more led to a few changes to the map table.  I put these into the ECU and then went for a 40 minute drive, taking care not to rev the engine too much and also not to apply too much throttle early on until the engine was thoroughly warmed up, and even then not using too much, just a few brief moments here and there.

Altogether, it went well – the engine feels OK, and although it’s not been over 4500 rpm for any length of time, it seems to go OK.  I can’t risk giving it too many revs or too much load for another few hundred miles, but I’ve gathered a fair bit of data and it shows that the mapping isn’t a million miles out for the areas that I have been using.  When I get back, I disconnect the LM-1, connect it to my old laptop (as it has a serial port, no new ones do), and then get this sort of thing out of it:

logging graph from a drive

This shows the RPM, throttle opening and air/fuel ratio, which are the three things needed to get the fuelling right on the engine.  Now, working out what is what from just a graph would be…. painful.  But thankfully the software can do analysis of all the points of data, and then present it in an easy-to-understand chart; some areas show more variation than others, and that’s to be expected as they are quite ‘wide’ rpm ranges (400rpm), so there is some averaging needed, but it’s way better than guesswork.  You get a table like this:

As you can see, I’ve been on full throttle, albeit briefly (there is another view that shows how many samples were taken – I was only on full throttle (and indeed anything above about 75%) for a few seconds.  These figures are mostly reasonable, but will need some fine tuning.  Once it’s run in I can use more revs and more throttle to get most of the rest of the map sorted; not all of it needs to be at the “maximum power” ratio; when you’re cruising on light throttle you can run a leaner mixture, saving quite a lot of fuel (especially as we will be spending a fair bit of time on motorways and A-roads).

All of this is good news, but it’ll still need some fine-tuning, which is now a fairly easy process as it really involves putting the current log and current map the logging software, turning a handle, and then a new map setting pops out – and again it’s a case of some deft Excel and Notepad++ work to get that back into the ECU without any chance of errors on my part!

On a slightly different note, my tickets arrived for Rallyday today, which is a week on Saturday – having the car ready for that is important as it’s the only “public appearance” I’ll be making before the closing date for Rally GB, so I want to try to get as many people as possible signed up on the day – I’m going to get the car stickered up and see what other promotional ideas I can come up with…