SG2 vs TDI

[Arragonis]

Hi,

Quick question - I've read a few posts about the SG2 not being much use on a TDI. My current car is a TDI (ASZ) and I am saving up for one. I have the on board mpg and ave mpg but I wondered about other stuff such as GPH and temps.

Is it still a good investment ?

And a question for the management - is the fulfilment better that the stickers and t-shirts if I order via Ecomodder ? I am in the UK and would like any moneys to go to ecomodder but I am still waiting for my stickers and an acknowledgement of my t-shirt question.

*(I do appreciate the site founders have others lives (wish I had one ) but even a quick email would be nice...)

[ChrstphrR]

Might want to check with the folks on TDIclub on that, since you've a newer generation of TDI, going onto the newest.

MkIV TDI (ALH) engines like mine don't seem to correlate their figures quite right to actual mileage. Or at least, I've found that you can get mileage to match, but then not the distance versus the odometer.

Another caveat, which the folks at TDIclub would be more apt to answer in greater detail: The newer instrument clusters are capable of displaying all sorts of information, but aren't as easily programmed so by the everyday driver, versus a Scanguage.

So, given those two caveats, you'll have consider your choice.

Myself, I live with a reasonably corrected mileage number from the SG2, and tolerate that the distance travelled is far under what the odometer measures. For me and my TDI, the SG2 is worth it for the extras like GPH, checking temperatures, voltages, etc.

And it helped me raise up my mileage considerably (10-20%) just by getting instantaneous feedback on the rate fuel is burned. After almost 2 years with mine plugged in, I have paid for it with the fuel saved.

[tasdrouille]

Originally Posted by ChrstphrR

Myself, I live with a reasonably corrected mileage number from the SG2, and tolerate that the distance travelled is far under what the odometer measures. For me and my TDI, the SG2 is worth it for the extras like GPH, checking temperatures, voltages, etc.

What settings did you use to get the fuel consumption right?

[ChrstphrR]

Originally Posted by tasdrouille

What settings did you use to get the fuel consumption right?

I'll give a run down of what I HAVE tried, alas without extensive data to show with it:

There's no ideal settings I've tried that work in all cases: The TDI ecu does seem to pull some trickery that the Diesel1/Diesel2 fuel types from the SG2 settings can't compensate for.

I've also tried adjusting the mileage counted out, to match distances, but I still ended up with inconsistent errors.
(There's another setting to adjust that, but I can't remember the option to get to it, but it is in the same sets of screens as setting the engine / fuel / display /etc.)


And, finally, what I do to compensate:

• Keep a pen and paper with me when filling up, and optionally, a cell phone with a calculator app.
• Record actual Odometer readings (I use the trip odometer since it will go to the 10th of a kilometer)
• Record the Tank mileage, distance, volume of fuel consumed, etc.
• Figure out the actual mileage based on my fuel receipt.
• Figure out the ratio of (Odometer distance/SG2 Tank distance)
• This yields a number (say, 1.04) that I use...
• when I go to the Fillup screen on the SG2, I *divide* the SG2 expected fuel amount on screen by the ratio of distances, to make my adjustment.
• And here's where the non-math based reasoning happens: City driving yields a different mileage than highway for my TDI, so, if I had an all Highway tank, and expecting a city tank, I'll adjust accordingly... or vice versa.

This seems to make the tankfuls I tracked wobble about the "ideal", and long term, it handles perturbations like doing a cross-Canada trip, then only do in-town driving for the next few tanks.

But you have to do your judgement on what your future driving will be on the current fill-up to keep from swinging well past 5% over/under. Sometimes that's not easy to predict.

Perhaps I just wasn't patient enough with calibrating with the distance/odometer correction first. It's hard to be that patient to try more than two-three tankfuls to calibrate, when each tank is now lasting me around 5-6 weeks!

[Arragonis]

Originally Posted by ChrstphrR

Might want to check with the folks on TDIclub on that...

Thanks - I shall have a search. Amongst TDISport forums it isn't mentioned much. Its getting more and more coverage on other forums though.

[tasdrouille]

Originally Posted by ChrstphrR

I'll give a run down of what I HAVE tried, alas without extensive data to show with it:

There's no ideal settings I've tried that work in all cases: The TDI ecu does seem to pull some trickery that the Diesel1/Diesel2 fuel types from the SG2 settings can't compensate for.

I thought you had found a solution to the problem with the SG2 being too optimistic at low rpm and too pessimistic at high rpm. That's why I was asking. Thanks anyway!

[ChrstphrR]

Sorry t'asdrouille! No, that's a better way to quantify the problem - city driving is low rpm, highway is higher rpm.

What the SG2 needs for us to fix the mileage discrepancy, are inputs for a second degree equation/curve so we can fit the fuel usage better for the RPM range.

More for the OP:

That said, it's still a useful tool! The other gauges and features, and the it's instantaneous mileage as a relative indicator of how you drive help reinforce good habits. It's going to be less accurate if you have a varying mix of city/highway driving, however.