02A Gearbox ratio suitability, ABF Scirocco mk2 track car

Discussion in 'Transmission' started by Joe_Pineapples, Jan 5, 2019.

  1. Joe_Pineapples New Member

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    Hi there,

    Hoping someone can advise which gearbox would be worth using from the selection I have available, or if I should be considering others? I'm intending to do an 02A conversion to my Scirocco mk2, using an ABF engine on 276 duration cams and Jenvey / lumenition ITB's and management. I have the engine and quite a lot of donor parts available including several gearboxes at hand. The engine is quite heavily modified and should be putting out decent power.

    I have a CHA gearbox available that came from a Passat TDi, a CDA box from a mk3 GTi 16v and also I think a DPA box from a later mk3 GTi 16v. The box is going to be fitted with an LSD before installation in car, and I've the option of swapping different gears out with assitance from a mate who knows a bit more than I do about such things. I've had a look through the forums and there seems to be little information on the CHA box, if I understand the ratios correctly, it looks like the CDA would have quite short ratios and a relatively longer 5th gear (motorway gear)? I don't want to compromise the acceleration and performance with anything stupid, and my knowledge is limited in this area. Wheels / Tyres will be 195 45 15.

    These would be used with a lightenend flywheel (6.5Kg iirc) and new uprated VR6 clutch.

    Thanks in advance!
     
  2. Jon Olds Forum Junkie

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    Find the combination with the lowest FD /closest ratios. I would use anything taller than a 3.89 final drive (from memory) A diesel gearbox
    will kill track performance.
    There are plenty of online ratio calculators around. 130/140mph top end should be plenty from a NA car.
    My mk2 golf rally car has a 5.2:1 FD !!
    Jon
     
  3. Joe_Pineapples New Member

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    Thanks Jon!

    CHA box has a 3.944 final drive, so on that basis it seems to be more suitable than most diesel boxes? Or would I be better advised to look for something like a 4.2 as found in some 02J boxes?

    Found the big gearbox thread and am looking at what's available...
     
  4. Jon Olds Forum Junkie

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    Play with your gearbox calculator and guestimate you min/max revs you will see while driving on the track. Look for the overlap between the
    gears. If you ae racing and your power band is 4000 to 8000 you would be always be in a gear well above 4000rpm, if that makes any sense
    Jon
    Nothing wrong with hitting the limiter in top 2/3 way down the straight.....
     
  5. dogzila Forum Member

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    Use CDA gearbox ratios with 4.24 final drive. You can find 02A gearbox with code CRU with 4.24
     
  6. Jon Olds Forum Junkie

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    Sounds like good advise, my mk1 runs a 4.2 and 0.91 fifth, good combo
    Jon
     
  7. Joe_Pineapples New Member

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    Thanks for the advice guys - I'd had a look and concluded much the same with regards to the 4.24 from the CRU 'box. Good to have it confirmed! WIll see what I can find. In the meantime, I have the stock ABF CDA 'box (3.68) and can fit the ring and pinion from the diesel box (3.944) to get some better performance. Considering fitting the .717 diesel 5th for motorway driving as well as an upgrade to the .838 from the stock ABF CDA box... I've some form of LSD to save up for before it's built, probably wavetrac going from reports on here, so I'll keep an eye out for a CRU box until then...
     
  8. Hotgolf Forum Junkie

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    I’m finding for great track combo’s is the 4.2 with a modified 02s 1st-5th. It’s short but keeps the abf on song better than stock 16v ratios.
    You can use 6th if you know a bloody good machine shop, but for most it’ll be beyond their skills or knowledge.
     
  9. Jon Olds Forum Junkie

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    Its a pity you don't run an 020 as I have a newly built FM code with quaife unused and not allocated to a project
    Jon
    Spend lots of time getting you gear linkage right as the 02A/F can easily be spoilt by poor gearchange quality
     
  10. Hotgolf Forum Junkie

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    If you are looking for something with a plate diff I also have a fresh built 020 with Kaaz.
     
  11. Jon Olds Forum Junkie

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    Hotgolf's box is the one for you, if you go for an 020.
    Jon
     

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