Gearbox swap 5 speed to 6 speed for Polo/Ibiza/Fabia/A1 1.6 TDI

As you may know, our Polo (1.6 TDI 90hp) is equipped with a 6-speed gearbox. This gearbox comes from a Seat Ibiza FR (TDI130). In this article, we're going to tell you the reasons for this swap, detail the list of parts needed to do it, as well as the work associated (not very different from changing a clutch after all) and above all the problems we encountered when swapping the gearbox on our vehicle, and which you'll also have to face if you decide to do the same swap.

Why change gearboxes?

The legitimate question to ask is: Why change the gearbox at all? The Polo's 1.6 TDI gearbox is fairly well geared, reliable and durable (the strongest of the VAG Group's 5-speed gearboxes), so why change it?

There could be a number of reasons: a desire to reduce fuel consumption, lower engine speed when driving on the highway, the desire to switch to a bigger OEM style (and price) clutch, or a desire for a stronger gearbox that can handle a lot of torque. Our vehicle falls into the latter category, just as much as the former: with 50,000 km/year, it consumes quite a lot of fuel, so lowering the bill, even by a few euros, has a significant impact on the annual fuel budget.

What should you consider?

To choose the best gearbox for you, you first need to know what you want to achieve with your car:

- to optimize fuel consumption, it's best to opt for a "long" gearbox in the gears you drive most often (90-110-130kmh, for example)

- if you're going for a drag setup, a short gearbox is better, as it allows you to rev up (and therefore accelerate) faster, so you can get to the "full boost" revs more quickly, and make the most of the car's horsepower.

- for advanced preparation, you need to define your objectives, in particular the torque and power you're aiming for, as well as other factors such as maximum torque revs, vehicle use and peripheral devices (cardan shafts, differential, etc.), to avoid ending up with repeatedly broken gearboxes.

Translated with DeepL.com (free version)