I'd like to do some logging with some specific values in mind, for example: engine rpm, throttle position, turbo pressure.

If I go to group logging, I can get some but not all of the combinations in a given group. So I have to use two or three groups to get what I want.

But choosing more groups slows the logging down.

So a couple of questions:

• Is it possible to define a custom set of three values to log simultaneously?
  
• I did see that you can chose individual values in the generic OBD2 logging section, but the choice is very limited and doesn't have all that I need.
  
• The "Turbo" buttom sometimes appears and improves logging speed, but I can't understand what it does and what are the downsides.
  
• Is the general speed limitation something to do with the software, the VCDS cable or the ECU / OBD interface? (ASZ engine on Fabia Mk1 with Bosch ECU).
  

Getting a sample rate of around 1 SPS isn't really enough. Chosing the turbo button on one log increases to around 7-8 SPS.

Essentially, what's the best way to obtain the maximum sample rate on a custom set of parameters?

Cheers

see 4.8 in http://www.ross-tech.com/vag-com/faq_4.html

You aren't going to do much better - not sure why you would need to.

Mapping.

I always stick to logging 1 group at a time.

Think the final bootle neck is the KWP protocol.

The reason behind this is more to gather telemetry for track days, along with high speed GPS logging to evaluate performance, etc.

So ideally, there'd be engine RPM against which there's also throttle and boost.

I can get rpm and boost in group 11, but that doesn't include throttle. In the groups where there is throttle, there's no boost.

So I was wondering if there's a way to create a "custom" group where I log just what I need so that the sampling rate is still quite high.

I'm not expecting to get the level of detail you'd get with a racing-designed ECU like a motec, but I'd like to optimise what I can with what's on the car

This is what I'm working towards

Harry lap timer would be good assuming you have an iPhone. Been meaning to get a wifi dongle to try it with.

No iphone, John.

Will tweak with improving what I can through VCDS. Bobby might have a few ideas too through his contacts

I've got an elm327 and some generic obd software. Will try and have a look this week to see what the sample rate is like.

If your handy you could write your own program

Just had a look at some old logs and logging RPM and 02 sensor (logging a petrol) I got an update every 0.3 seconds. Logging RPM, MAP and MAF I got an update every 0.5 seconds.

Well, we've probably found one method of improving it and that's creating a single custom group which logs the three values I'm after (rpm, boost and throttle) and coding in the map loaded on the ECU.

Will give it a try soon and report back. But it's hardly a flexible user-applicable solution and more a permanent custom-made one...

Been meaning to try that method. Hmm might need to play