Just been out on the A5 doing some logging, comments welcome on the plots. These are for fault finding in the hope I can discover whats causing my low MPG at the moment.

The car is a Jabba remapped Octavia 1.8T

Glad to hear the cable arrived

My only confusion is with the boost - It says PSI, but the plot only goes up to 2.5. Thats a tiny amount of PSI boost. Am I missing something with that one? The fact you get less than requested boost low down might have something to do with your poor economy, and notice it goes OK around 3500+ - that could be due to your MAF cleaning and your note it improved from 4000.

The other two appear normal as well.

edit: Just noticed with the boost it starts at 1, so it must be in bar, hence max boost of around 1.2 bar.

The axis label should be "bar" - I think.

I think the MAF reading is OK - Ewe (Mr VAG-COM) says 80% of the car's bhp is what you'd expect to see on a 1.8T which comes to 175 g/s - about what I've got here.

I should of course, say thanks to Jon for the loan of his cable Mine has stopped working :(

Phil,

Try logging the Lambda readings, they should be close to 1 on low throttle/cruise and drop to around 0.75 - 0.85 ish above3.5-4K if it is dropping to say .6 then the car is running too rich higher in the rev range.

You will need to log block 031 along with something like 003 to get the RPM range have you also checked your spark plugs to see what colour they are?

That's definetely Bar on the boost graph but it would appear that Phil has forgotten to deduct atmospheric pressure before plotting the graph.

Boost graph looks fine although you could run more boost than currently.

Peak figure for the MAF seems about right but the graph doesn't look as smooth as plots I've seen from healthy cars.

What do you use to get this data - is it homebrew cable/software as I have been thinking of having a 'play' with this for a while!!

Thanks for the pointers, I'll try logging the lambda data later this evening.

VAG-COM is what was used to get the data from the car. I then used excel to do the plots.

Why is there soooooo much turbo lag?

Full boost at 3500rpm seems a bit odd for a car with a standard turbo? I'd have thought it should be reaching maximum at 2200 - 2500rpm?

Why is there soooooo much turbo lag?

Full boost at 3500rpm seems a bit odd for a car with a standard turbo? I'd have thought it should be reaching maximum at 2200 - 2500rpm?

People tha have driven my car have said that too, I think its a characteristic of my jabba remap as those who've driven it have other remaps and dont suffer the same lag.

However, it does make the car feel fast.