6 speed gearbox

But what would be benefit in FSI transmission? It's still 5q, isn't it? And what's the probability to find a Lupo GTI box?

I always wonder when I read posts about adding an extra "long" gear.
Sure, a longer gear gives lower revs at the same speed, but, surely, you will now need the same amount of energy, at the lower revs than at the previous higher revs, since the load, (pushing the car along) is the same?
So, since the energy comes from the fuel, I can't see where the improvement is economy is going to come from.
Mac.
Yes and no. Each engine has various fuel consumptions for same power output but in different RPM. It's usually plotted in BSFC map for whole engine power range. And according to this map, manufacturer tries to create gear ratios according to specific speeds car is usually driven. For our case A2, was never meaned to be driven most of the mileage on the highways but in the town and country road with limits 50 km/h, 70 km/h or 90 (100) km/h and when you look at the gear ratios for each gear and speed above, you will notice correlation between speed and RPM in specific gear. All of this means that there is missing 6th gear in 1.4 TDI because it revs stupidly high on the highway and petrols won't be much different...
 
But what would be benefit in FSI transmission? It's still 5q, isn't it? And what's the probability to find a Lupo GTI box?


Yes and no. Each engine has various fuel consumptions for same power output but in different RPM. It's usually plotted in BSFC map for whole engine power range. And according to this map, manufacturer tries to create gear ratios according to specific speeds car is usually driven. For our case A2, was never meaned to be driven most of the mileage on the highways but in the town and country road with limits 50 km/h, 70 km/h or 90 (100) km/h and when you look at the gear ratios for each gear and speed above, you will notice correlation between speed and RPM in specific gear. All of this means that there is missing 6th gear in 1.4 TDI because it revs stupidly high on the highway and petrols won't be much different...

I’m not sure re the fsi gearbox but it will fit, the lupo gearbox would be findable if you wanted to, there aren’t maybe lupo gti left however.

There is however a conversation path for an fsi so this could be converted and put on a 1.4 with messing of the final drive.

FYI about the 02T MQ200 family



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But what would be benefit in FSI transmission? It's still 5q, isn't it? And what's the probability to find a Lupo GTI box?


Yes and no. Each engine has various fuel consumptions for same power output but in different RPM. It's usually plotted in BSFC map for whole engine power range. And according to this map, manufacturer tries to create gear ratios according to specific speeds car is usually driven. For our case A2, was never meaned to be driven most of the mileage on the highways but in the town and country road with limits 50 km/h, 70 km/h or 90 (100) km/h and when you look at the gear ratios for each gear and speed above, you will notice correlation between speed and RPM in specific gear. All of this means that there is missing 6th gear in 1.4 TDI because it revs stupidly high on the highway and petrols won't be much different...
I'd think that a remap, to suit the new ratios, would deliver better economy, not convinced a longer top gear, on it's own would.
Mac.
 
Our TDi engines have a sweet spot for fuel economy and it's usually around the peak torque rpm - say 1700 to 2000 rpm. (which is what Big Bang was eluding to)
As engine speed increases more energy is wasted in friction losses etc which has a negative impact on fuel consumption.
Optimising the gearing to match the desired cruising speed at the above rpm should therefore improve economy and having 6 gears makes it easier to keep the engine rpm in the sweet spot under other driving conditions.

The theory should also apply to petrol engines but finding a suitable 6 speed box could be difficult. May be wrong but I suspect the Lupo GTi has a close ratio box for performance rather than an overdrive 6th

Cheers Spike
 
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Just had a quick hunt on 7zap - unfortunately the Q2 / T-Roc / Ateca are too recent to be featured.

I've never seen the numbers before, but was surprised that the FSi gearbox is actually slightly undergeared compared to the 1.4i (98.7% of the ratio in each gear owing to a different final drive ratio).

Looking within the parts list for the A1 with the 02T / related 02U boxes I would have a moderate concern that 6-speed gearboxes designed for the small petrol turbo engine are geared far too high in 6th to be usable.

There is one A1 5-speed 02T gearbox (LGQ) that has a final drive ratio about half-way between the A2 petrol and diesel boxes. 1st gear is 98.1% that in the AUA A2 ; 2-4th are 14.8-18.5% higher, and 5th is 7.1% higher than the A2. This may be feasible as it doesn't seem to be interstellar and dependant on torque at 2000rpm where the petrol engines don't have much (assuming it fits - the casing diagram looks as similar as the PTW to GPK comparison for Tdi conversions).

The A1 6-speed 02U boxes with codes LMD, NBV / PRM barring 1st, are 16.7-20.1% higher (2nd to 5th) than the FSi gearbox gear by gear, with 6th gear geared for approximately 63mph at 2000rpm (final ratio is 0.451 where 5th gear in the AUA is 0.317 and FSi 0.313 and the LGQ 0.340). I suspect this would be simply too much, so 5th (0.373) at most usable on the motorway, and in this instance, I don't see an advantage over the 5-speed box as it is more gear 5.5 than 5.
 
Engines have a sweet spot for fuel economy and it's usually around the peak torque rpm - say 1700 to 2000 rpm. (which is what Big Bang was eluding to)
As engine speed increases more energy is wasted in friction losses etc which has a negative impact on fuel consumption.
Optimising the gearing to match the desired cruising speed at the above rpm should therefore improve economy and having 6 gears makes it easier to keep the engine rpm in the sweet spot under other driving conditions.

The theory should also apply to petrol engines but finding a suitable 6 speed box could be difficult. May be wrong but I suspect the Lupo GTi has a close ratio box for performance rather than an overdrive 6th

Cheers Spike
Hmmm, does friction increase with engine speed (we're only talking a few hundred rpm here)?
I agree about the sweet spot, but that sweet spot will have been mapped to match the OEM gear ratios.
Moving the car at a given speed takes a given amount of energy, energy that comes from the fuel. Changing gear ratios doesn't change that.
I think the assumption that fuel consumption, at a given speed (and load etc), will decrease if engine rpm is decreased, is false, unless the engine characteristics are changed (ie re mapped) to match.
For sure, any improvement in mpg when motorway type cruising will be miniscule compared to the cost (and risk) of the work involved.
Mac.
 
I think a remap on the 1.4 petrol is not only a more cost affective choice but economy will be improved with the new rpm peramitters, I intend having a map done to mine for the sole purpose of improving economy and in gear driveability and not for performance as we all know that would be minimal.
That all said and done if a 6 gear option was achieved with success then it would be of interest but I don't see that being a viable option at present.
 
I think a remap on the 1.4 petrol is not only a more cost affective choice but economy will be improved with the new rpm peramitters, I intend having a map done to mine for the sole purpose of improving economy and in gear driveability and not for performance as we all know that would be minimal.
That all said and done if a 6 gear option was achieved with success then it would be of interest but I don't see that being a viable option at present.
I had both of my A4 V6 Quattro Tiptronic TDis remapped, a few years back, and in both cases the power and economy was improved.
I think your plan for the 1.4 petrol is very logical. The 1.4 petrol does seem to be the ideal A2 for everyday driving in the 2020s.
Mac.
Edit: Both A4s are long gone.
 
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I'm surprised no one has mentioned the MYP 6 speed conversion as an option to the OP. I was mulling doing this on one of my A2's soon as it is likely to start doing more motorway miles. from reading threads in the past the potential downsides are that it will only be held on with 2 bolts instead of 3, brackets are required for cable supports (easily fabricated) and the starter might need changing to the one that originally came with the MYP gearbox.

Trevor
 
Hmmm, does friction increase with engine speed (we're only talking a few hundred rpm here)?
I agree about the sweet spot, but that sweet spot will have been mapped to match the OEM gear ratios.
Moving the car at a given speed takes a given amount of energy, energy that comes from the fuel. Changing gear ratios doesn't change that.
I think the assumption that fuel consumption, at a given speed (and load etc), will decrease if engine rpm is decreased, is false, unless the engine characteristics are changed (ie re mapped) to match.
For sure, any improvement in mpg when motorway type cruising will be miniscule compared to the cost (and risk) of the work involved.
Mac.

Friction plus other 'pumping' and mechanical losses increase with the square of engine rpm.
Simple test to prove (or disprove) the engine rpm effects on economy would be to drive the car in 5th at around 1800 rpm and check fuel consumption then maintaining the same road speed, try it in 4th

Most agree the 6 speed conversion is not cost effective regarding any fuel economy gains but the smallish drop in cruising engine rpm does improve refinement.

Easiest way to improve economy is to drive slower. Horsepower is proportional to speed cubed so cutting speed from 70 to 65 needs about 25% less power (hope we have no maths teachers in the house)

Not sure about remapping the petrol engines. I think a few have tried on the FSI and been disappointed. It would be useful to check a 'mapped' torque curve to ensure the gains are not only at higher rpm at the expense of bottom end torque

Cheers Spike
 
I'm surprised no one has mentioned the MYP 6 speed conversion as an option to the OP.
The thread was originally started in 2009 by a TDI owner for whom the MYP would indeed have been a good option. But the current enquiry in Post 15 is from a 1.4 petrol owner: I've always understood that the MYP box wouldn't be physically compatible with that engine, it's far too high geared for it anyway.
 
The thread was originally started in 2009 by a TDI owner for whom the MYP would indeed have been a good option. But the current enquiry in Post 15 is from a 1.4 petrol owner: I've always understood that the MYP box wouldn't be physically compatible with that engine, it's far too high geared for it anyway.
Ah, got it. I did spot that the thread had wandered onto petrol options but didn't look at the dates.
 
Hmmm, does friction increase with engine speed (we're only talking a few hundred rpm here)?
I agree about the sweet spot, but that sweet spot will have been mapped to match the OEM gear ratios.
Moving the car at a given speed takes a given amount of energy, energy that comes from the fuel. Changing gear ratios doesn't change that.
I think the assumption that fuel consumption, at a given speed (and load etc), will decrease if engine rpm is decreased, is false, unless the engine characteristics are changed (ie re mapped) to match.
For sure, any improvement in mpg when motorway type cruising will be miniscule compared to the cost (and risk) of the work involved.
Mac.
No one has mentioned that reduced revs in theory also has an impact on overall engine life (reduced wear from fewer engine revolutions for mileage covered). Impact on fuel consumption may be minimal but the benefit is really refinement of having a quieter engine.
 

Friction plus other 'pumping' and mechanical losses increase with the square of engine rpm.
Simple test to prove (or disprove) the engine rpm effects on economy would be to drive the car in 5th at around 1800 rpm and check fuel consumption then maintaining the same road speed, try it in 4th

Most agree the 6 speed conversion is not cost effective regarding any fuel economy gains but the smallish drop in cruising engine rpm does improve refinement.

Easiest way to improve economy is to drive slower. Horsepower is proportional to speed cubed so cutting speed from 70 to 65 needs about 25% less power (hope we have no maths teachers in the house)

Not sure about remapping the petrol engines. I think a few have tried on the FSI and been disappointed. It would be useful to check a 'mapped' torque curve to ensure the gains are not only at higher rpm at the expense of bottom end torque

Cheers Spike
Remap an FSI? Nooooo never. Don't even think about it! (ProBoost excepted).
In good fettle they go well as is. If poorly, they need a bit (a lot, probably) of love (and pennies).
I do think the 1.4 petrol could benefit from a modest remap though.
Mac.
 
A six speed with closer ratios would help to make the most of the 1.4's lesser torque by keeping the engine "on the boil" and might bring benefits but at the expense of increased clutch and gear cable wear (not to mention left knee)
Increasing the final drive ratio by even a few % would dent the performance noticeably (been there with other underpowered vehicles)
Then of course there is a weight penalty, but it is small.
It all looks like trying to make a small light urban car into something that it wasnt meant to be.
It would be cool though.
 
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