Hi all,
So I've been doing some research on the 6 speed gearboxes mentioned by forum members as having been successfully used for / proved suitable for this conversion from experience, and what cars they can be sourced from - thought I'd share the below info taken from EKTA by one of the mods from another VAG forum I'm on for us all:
Suitable gearboxes that are known to work, from forum members' experiences so far: MYP, PTU, PTW, NTG
The MYP is fitted to 2 VAG models:
Manufacturer: VW, Date(s) Used: 08/2010-12/2014, Model: Passat/Variant/4Motion, Passat 1.6 TDI-CR, Transmission Code: MYP, Transmission Type: 6S, Remarks: 02S Gearbox (front-wheel drive) - <note that EKTA does not refer to BlueMotion, only 4motion>
Manufacturer: Skoda, Date(s) Used: 05/2013-05/2015, Model: Superb, Transmission Code: MYP, Transmission Type: 6S, Remarks: 02S Gearbox (front-wheel drive)
The PTU is fitted to 2 VAG models:
Manufacturer: Audi, Date(s) Used: 02/2014-05/2015, Model: Audi A3 Cabriolet, Transmission Code: PTU, Transmission Type: 6S, Remarks: 02S Gearbox (front-wheel drive)
Manufacturer: Audi, Date(s) Used: 02/2013-05/2015, Model: Audi A3/S3/Sportback/Limousine/Quattro, Audi A3 1.6 TDI-CR, Transmission Code: PTU, Transmission Type: 6S, Remarks: 02S Gearbox (front-wheel drive)
The PTW is fitted to 5 VAG models:
Manufacturer: Audi, Date(s) Used: 09/2013-05/2015, Model: Audi A3/S3/Sportback/Limousine/Quattro, Audi A3 1.6 TDI-CR, Transmission Code: PTW, Transmission Type: 6S, Remarks: 02S Gearbox (front-wheel drive)
Manufacturer: VW, Date(s) Used: 05/2014-05/2015, Model: Golf Sportsvan (SV) 1.6, Transmission Code: PTW, Transmission Type: 6S, Remarks: In 2014 an all-new successor to the Golf Plus was revealed, the Golf Sportsvan (SV), 02S Gearbox (front-wheel drive)
Manufacturer: VW, Date(s) Used: 05/2013-05/2015, Model: Golf/Variant/4Motion 1.6 BlueMotion, Transmission Code: PTW, Transmission Type: 6S, Remarks: 02S Gearbox (front-wheel drive)
Manufacturer: Seat, Date(s) Used: 09/2013-, Model: Leon, Transmission Code: PTW, Transmission Type: 6S, Remarks: 02S Gearbox (front-wheel drive)
Manufacturer: Skoda, Date(s) Used: 05/2013-05/2015, Model: Octavia, Transmission Code: PTW, Transmission Type: 6S, Remarks: 02S Gearbox (front-wheel drive)
The NTG is fitted to 1 VAG model:
Manufacturer: Audi, Date(s) Used: 10/2012-02/2013, Model: Audi A3/S3/Sportback/Limousine/Quattro, Audi A3 1.6 TDI-CR, Transmission Code: NTG, Transmission Type: 6S, Remarks: 02S Gearbox (front-wheel drive)
Other candidate gearboxes which appear to be from the same "family" - 6 speed O2J / MQ250 - that I've not been able to eliminate as definitely not being paired from the factory with the 1.6 TDI engine are NBH, QWW and QBP - fitted to the Audi A3, Seat Leon, Skoda Octavia - same variants & years as where this model is mentioned above;
I've also attached my version of the gearbox ratio spreadsheet provided by
@Robin_Cox (Thanks Robin!) that contains the gearing information on all of the above proven candidate gearboxes, plus I've deleted some of the 5 speed gearbox lines to leave just the standard TDI 75 and 90 ratios for comparison purposes, and added some additional calculations to take into account different tyre sizes, various RPMs vs MPH scenarios in each gear etc. to make it more useful.
Conclusion: From this research - built upon the foundation of the many pages of this wonderful thread among others in particular - I'm now in the market for a PTW gearbox as a first preference; due to the longer gearing in each gear when compared to the other three 6 speed gearboxes when the different final drive ratio is taken into account.
This is particularly so in the lower gears, which as I'm planning to buy a re-mapped TDi90, I think will be ideal to avoid too much cog swapping around town - Here is that difference in each gear, expressed both in actual MPH at 2000 RPM and as as additional % over the corresponding gears of the MYP / PTU / NTG, which are more or less identical to the corresponding gears of the standard TDI 75 (up to 5th gear of course):
View attachment 66294
I would think the longer 3rd gear in particular is going to contribute to this upgrade nicely in terms of urban road manners: 30 MPH will correspond to about 1700 RPM, so there should be less gear changing required around town in freely moving traffic (I don't accelerate quickly in this type of environment), with the taller lower gears nicely matching the remapped TDI 90's spread of torque low down - thanks in part to it's variable vane turbo.
Whilst in top gear with standard or slightly taller tyre sizes the revs would be as follows:
175/60/15, 1857mm circ. (Std): 1998 RPM at 70mph vs the 2028 RPM with the MYP
175/65/15, 1910mm circ. (Std +3%) 1940 RPM at 70 MPH vs 1972 RPM with the MYP
EDIT: I've just found a PTW 'box and starter motor from a breaker on eBay in Cornwall from a 2013-16 Seat Leon 1.6 TDI with 35,000 miles on it and bagged it for £475 delivered! Now on it's way to my restoration / restomod specialist of choice! Also I've found a good used Audi A3 Sport 6 Speed Black Leather Gear Knob (part code 8P0863279) for £9 which I'll use as a donor for the six speed gear knob emblem for the car's current gear knob for that OEM look!