Which Gearbox Ratios?

[southpaw66]

As no-one's picked up my comments in previous threads when comparing TDIs and TFSIs etc. over the past weeks...

Does anyone know where I can find info on which gearbox is fitted to 140TDI, 170TDI , 2.0TFSI and S3 with respective ratios and final drives?

I'd like to try and do some calculations to once and for all work out the on-the-road comparison of these cars, because the endless debate about torque curves and power output of the engines especially comparing TDI to TFSI is getting on my nerves. What matters is torque/power to the wheels, that's what makes the car move forward.

We did the same calculations at University, but it was more than 10 years ago now so it may take me a while (days/weeks) to get them right but I'd be happy to post some graphs when complete.

Cheers.

 

[dummi]

try ETKA.

 

[southpaw66]

OK I've just had a look and theoretically it may be possible to calculate the ratios from the number of teeth specified and working out which cogs mesh but it'll take too long and high risk of error.

What I need is a table like those sometimes used in some magazine roadtests, might be 'what car?'. Anybody got mag reviews for A3s with the ratios listed?

Thanks.

 

[HeliChris]

Hi Southpaw66

I totally agree with you about the gear spacing / final drive ratio being of equal importance to the performance equation. It would also be interesting to look at the weight of a TDI over TFSI.

From my experience German cars, are in general focused on top speed, and as a general rule the quotes top speed will be achieved at the engines quoted peek power. The exceptions to this are 155mph limited cars. I have driven loads of German hire metal up and down the Autobhans, so I speak from experience, but there are exceptions.

So you could take the peak power quoted and the top speed quoted, with the standard factory spec tyres to get a rough guide to the gearing being used.

Chris.

 

[southpaw66]

Thanks Chris. I will be using this information to help assess driveline losses and wind resistance as the theoretical engine peak power and gearing should give a higher figure than actually realised in practice.

There has to be tables written down somewhere, I think they are actually in the press packs so should be re-published somewhere. Volvo certainly publish their gearbox details and even power curves for engine.

 

[southpaw66]

Done some digging (ETKA and lots of forums) I've got some possible figures for 2.0L petrol and diesel so far. I'll starting trying to work some of this out. But if anybody finds old tests with ratios would be great as confirmation and still need quattro.

 

[h5djr]

I have access to the ELSAWIN electronic workshop manual for the A3. I have looked at the details given for gearboxes and below is a link to a pdf file giving the details of the 02Q 6-speed manual gearboxes fiited to the 2.0TDI-170. If this is the sort of data you're looking for, let me know and I will prepare pdfs for other models and gearboxes.

gearbox-02Q

 

[southpaw66]

h5djr - Perfect! Much Appreciated.