5th Gear upgrade

[manwithtool1]

Has anyone upgraded their 5th gear. What I actually mean is change the ratio. On the T4 forum it's a common mod to change the 5th gear ratios and raise the road speed you do at a given revs. My A3 1.8T currently does 70 mph at 3000 revs and to me this seem too high revs for that speed. My 2.0 petrol van does that and has half the power and twice the weight....well almost. I've had a look and the fifth gear arrangement is identical so I see no reason why 5th gear couldn't be altered. I've searched the forum and no one seems to have done it.

Anyone got any comments or advice ? For me it seems easy as my standard van gearing seems to be a higher ratio than the std Audi gearing. I'll have to do the maths but I guess I would be aiming for 75-80 mph at 3000 rpm

Thanks

 

[Prawn]

I can't really see what you hope to gain from doing this?

Does 3000rpm at 70 offend you?

The most logical solution would be to convert to a 6 speed 02M box, which would lower revs at 70 to around 2700, but I'd still say that's no good reason to go through all that work.

 

[Alex C]

3000rpm at 70

!! how very dare you

 

[manwithtool1]

OK 70 at 3000 rpm does offend me. Takes about 90 minutes to change the gears which I have anyway. So a lot easier than swapping a gearbox. Just seem to me that the engine could pull a higher gear. As I said I did it on my gutless heavy van and it's fine.
Just to be clear all you have to do is remove the end cover to access 5th gear, so it can be done in situ.

 

[VAG-Slag]

Again, I don't really see what the problem is here...

But if you really did want to do something about it, 5th gear from a 02J diesel gear box would be a fair bit longer...

Is it a non-turbo A3?

 

[manwithtool1]

Again, I don't really see what the problem is here...

But if you really did want to do something about it, 5th gear from a 02J diesel gear box would be a fair bit longer...

Is it a non-turbo A3?

No it's a 1.8T , I just have a thing about revving an engine over 3000 on a run. I absolutely love this car apart from the cruising revs. I think they design these cars to go 70mph with 4 people and luggage towing a caravan. So running with 2 people should be easy at a higher speed. Same principle with my T4, designed to run with 1 tonne on board, but I never have that weight !

 

[manwithtool1]

Well in case anyone feels like me the gears I'm going to fit are 34 teeth and 45 (ratio 0.756) originals are 36 and 43 (ratio 0.8372) This should give me a road speed of 77 mph instead of 70 if I've done my sums right !
If anyone wanted a set of gears they are on ebay or go on the T4 forum and find someone who's upgraded theirs and has the lower ration available.
I do realise that this doesn't mean I get more mpg and I'm not sure if it's going to make my speedo mis read. The van speedo was on the output shaft so it still read ok where the A3 has it on the gear box so I have no idea if it will read right.

 

[manwithtool1]

Loads of info on swapping the gears on the T4 forum.

 

[Stuart B]

These 1.8T cars are pointless driving under 3000 rpm as they are not responsive enough to accelerate without changing down a gear.
Are you just going to drive at 77mph now?

 

[manwithtool1]

well no more than you're driving at 70. But seriously mine pulls like a train from 2000 rpm.

 

[Stuart B]

do you have a different turbo? maximum torque is 3500 on most S3s - maybe I need a new turbo I have heard people saying they hear it "spinning up" at 2500rpm after replacing bits and pieces.

 

[snowy]

K03S
KO3

 

[manwithtool1]

As far as I know it's all standard. I have a boost gauge and it reads up to about 7-8 psi. And it's an A3 not an S3

 

[Stuart B]

oh I see a smaller turbo comes alive at lower revs.

 

[manwithtool1]

Yep, I believe a smaller turbo spins up quicker and gives a bit more torque at the expense of power.

 

[snowy]

I needed to do similar with O2M gear ratios for similar reason

 

[manwithtool1]

Well I had to replace the clutch on the A3 (slipping) so while the box was off I swapped the gears. Much much nicer now on the motorway and I can still bimble along in 5th at 40-45 ish. Replaced the rear crank seal while the flywheel was off. Loving this car ! only paid £650 for it just over a year ago and including the clutch and bits it still only owes me about £1100. So quiet, nippy and reasonably good on fuel.

 

[badger5]

bigger diameter wheels..

 

[manwithtool1]

LOL....
5th gear upgrade if you bought the gears would cost £300 ish. If you get on the T4 and T5 forum a set of std gears would probably cost you £50 as lots of van owners upgrading and the std ones from my van were just the right ratio. A reminder that you can do all of this with the gearbox in place. Access via the cover at the end of the gear box.