We now have a bolt in 6 speed gearbox for the FSI

Internet suggests Mk 5 Golf FSI ratios are:

1st gear: 3.46:1
2nd gear: 1.96:1
3rd gear: 1.28:1
4th gear: 0.98:1
5th gear: 0.81:1
6th gear: 0.71:1

Mac.
 
What about final drive/diff ratio?

Sent from my SM-N960F using Tapatalk

1st gear: 3.46:1
2nd gear: 1.96:1
3rd gear: 1.28:1
4th gear: 0.98:1
5th gear: 0.81:1
6th gear: 0.71:1
Final transmission:4,53:1
RPM at 120 km/h: 3.200 rpm (Mk5 Golf FSI),

Note: I cannot guarantee the accuracy of these figures. Source looks good thoiugh.

Mac,
 
A 6th gear is appealing to me from the point of view of a longer 6th reducing rpm at motorway cruising speeds. With the 5 speed box yielding 70 mph at 3200 rpm in 5th it seems not much gain. 120km/hour = 74.6 mph.

Well done for giving it a go.

Andy
 
Let's assume that the gear ratios posted by Mac above are indeed correct.

Mk5 Golf FSI -
1st gear: 3.46:1
2nd gear: 1.96:1
3rd gear: 1.28:1
4th gear: 0.98:1
5th gear: 0.81:1
6th gear: 0.71:1
Final transmission: 4,53:1

A2 FSI -
1st gear: 3.45:1
2nd gear: 2.10:1
3rd gear: 1.39:1
4th gear: 1.03:1
5th gear: 0.81:1
final transmission: 3.93:1

When doing RPM vs. speed calculations, we need to remember that both gearboxes will be using the A2's wheel/tyre size. For this purpose, I have assumed that we're using the standard SE alloys with 185/50/R16 tyres. This means...

Standard A2 FSI gearbox in 5th: 3216rpm at 70mph
Mk5 Golf gearbox in 6th: 3249rpm at 70mph

So, the Mk5 6-speed box seemingly compresses 6 gears into the range of the existing 5. It actually increases revs by 33rpm at 70mph.

Again, this assumes that the gear ratios listed above are correct. If we knew the gearbox code, that would definitely help to verify the accuracy of our data. I have an accurate record of the FSI's gear ratios, but they're not immediately to hand.

Cheers,

Tom
 
Let's assume that the gear ratios posted by Mac above are indeed correct.

Mk5 Golf FSI -
1st gear: 3.46:1
2nd gear: 1.96:1
3rd gear: 1.28:1
4th gear: 0.98:1
5th gear: 0.81:1
6th gear: 0.71:1
Final transmission: 4,53:1

A2 FSI -
1st gear: 3.45:1
2nd gear: 2.10:1
3rd gear: 1.39:1
4th gear: 1.03:1
5th gear: 0.81:1
final transmission: 3.93:1

When doing RPM vs. speed calculations, we need to remember that both gearboxes will be using the A2's wheel/tyre size. For this purpose, I have assumed that we're using the standard SE alloys with 185/50/R16 tyres. This means...

Standard A2 FSI gearbox in 5th: 3216rpm at 70mph
Mk5 Golf gearbox in 6th: 3249rpm at 70mph

So, the Mk5 6-speed box seemingly compresses 6 gears into the range of the existing 5. It actually increases revs by 33rpm at 70mph.

Again, this assumes that the gear ratios listed above are correct. If we knew the gearbox code, that would definitely help to verify the accuracy of our data. I have an accurate record of the FSI's gear ratios, but they're not immediately to hand.

Cheers,

Tom
One reason for having a closer ratio 6 speed box is that the engine is mapped with a narrow power band. (I believe this is the primary reason for the proliferation of 6,7,8 etc speed boxes, not so much to lower revs at cruising speed). Maybe the FSI engine in the heavier Mk5 Golf is mapped differently to the lighter A2.
It's likely performance v economy etc was given quite a lot of thought during the development of the FSI (indeed all variants). Let's give those engineers a bit of credit, after all, they had a wide choice of boxes and ratios from which to choose, so, it seems likely, to me anyway, that OEM is the best compromise ...
Mac.
 
One reason for having a closer ratio 6 speed box...
The gear ratios aren't especially close when used in its intended vehicle. On average, the Mk5 Golf uses tyres that have a 7.3% larger rolling circumference than those used by the A2. This means that, in a Mk5 Golf, the 6-speed gearbox achieves approximately what we're looking for: 5 gears of similar length to those we know and love, plus a 6th gear for reduced-rev motorway cruising. Unfortunately, when combined with the A2's smaller wheels, the ratios aren't long enough. Tyre size is effectively part of the final drive ratio, after all.

Cheers,

Tom
 
Last edited:
How feasible would it be to fit an alternative ratio diff, to give longer gearing?

Sent from my SM-N960F using Tapatalk
 
Not so sure the FSI has enough torque to drive a higher ratio. Not really much below 3000rpm

Sent from my SM-N960F using Tapatalk
 
If you had a longer top gear, on an FSI, dropping the engine speed below 3000 rpm, at 75 mph, you'd probably need to change down on gentle climbs, which you don't notice in standard 5th! -
Again, maybe the designers weren't so daft!
Mac.
 
A bit of background. This company (https://www.getriebetechnik-sachsen.de/leistungen) in Germany has been offering a 6-speed upgrade for the FSI for a few years. The upgrade adds a 6th gear to the standard 5-speed gearbox, thus dropping revs at motorway speeds. It uses the same engineering principles as the 6-speed conversion for the TDI gearboxes. It works excellently and has had universally positive reviews from those who have taken the plunge. However, it's expensive (circa £1600 by the time you've accounted for shipping, gearbox removal/reinstallation, etc).
The very fact that this company offers the upgrade is, to my mind, a clear indication that a bolt-on gearbox from the VAG range that achieves the same objective doesn't exist. It is also, however, a clear indication that there's a demand for the upgrade, which probably wouldn't exist if it didn't work well. Perhaps the designers who put a 5-speed gearbox in the A2 knew that a 6th gear would be ideal, but were overruled by the accounts department?

Cheers,

Tom
 
Comparing the first gear ratios on the 5-speed and 6-speed gearboxes using A2 wheels shows that the 5-speed gearbox has about a 15.6% higher first gear. Someone using this 6-speed gearbox might find the first gear too low for use in the A2, or at the very least not ideal. The 6-speed gearbox is after all made for a car which uses not only bigger outside diameter tyres, but is considerably heavier than the lightweight A2...hence needs a considerably lower 1st gear to account for these differences.

Mk5 Golf FSI - (6-speed gearbox)
1st gear: 3.46:1
2nd gear: 1.96:1
Final transmission: 4,53:1

A2 FSI - (5-speed gearbox)
1st gear: 3.45:1
2nd gear: 2.10:1
final transmission: 3.93:1
 
How feasible would it be to fit an alternative ratio diff, to give longer gearing?
Steep hill starts could be a problem though...
Comparing the first gear ratios...
This is another good point. I'd only been looking at the top gears, but the short gears are also less than ideal. It does mean, theoretically at least, that the final drive could be lengthened without creating hill-start problems.

I've never seen the inside of the FSI's gearbox, but if it's anything like the TDI's 'box, increasing the length of the final drive is quite an involved process, because the toothed wheel that drives the diff' is an integral part of the gearbox's output shaft. You therefore need to swap all 6 gears onto alternative shafts.

Cheers,

Tom
 
Back
Top