MK3 16v head or 9a head?

Discussion in '16-valve' started by kevh, Jan 13, 2004.

  1. kevh Forum Member

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    Was just asking if there are many advantages of using one of these over the other, fortunately i have both and there are slight differences, which one will give better performance once gas flowed and minimal porting?
     
  2. TheSecondComing Forum Addict

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    Original head is meant to be very slightly better as stock, but the 2 litre head has more meat in it to be ported out.
     
  3. kevh Forum Member

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    there both 2 litre heads but are slightly different
     
  4. velly_16v_cab

    velly_16v_cab Forum Junkie

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    doesnt the mk3 have a bigger exhuast valve???

    when flowed you 'shown' have a better flow rate on the other
     
  5. prof Forum Addict

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    nope, think they are smaller but the seat size is the same
     
  6. TheSecondComing Forum Addict

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    Shoulda read the post properly, shouldn't I... thought you were talking about KR/9A heads..... [:$]
     
  7. kevh Forum Member

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    the mk3abf head has different shape combustion chamber than the 9a head, the 9a head looks similar to the kr head. which head achieves the best power when ported?
     
  8. prof Forum Addict

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    really? thought they were the same as 9a?

    ABF head allegedly has the best exhaust flow out of all of them, speak to www.stealthracing.co.uk
     
  9. Fozzie_Bear Forum Member

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    Thats what I've haerd to that the BAF is better. The ABF is a 351 casting and not 051/ 026/027.
    The exhaust ports are much better in design although the inlets are not as good as the 026/7 heads.
     
  10. kevh Forum Member

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    the shaping of the inlet and exhaust ports look the same on the two heads, but fortunately had a kr exhaust valve and checked the size against the 9a head and they r the same size. the abf head was a bare head with no valves so cant check them.
     
  11. Fozzie_Bear Forum Member

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    What are the head numbers on the ones you have there. I've seen people pulling off mk3 heads to find that they have 051 castings instean of 351.
     
  12. kevh Forum Member

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    they have the same casting numbers but the mk3 one has a extra letter at the end
     
  13. GVK

    GVK Paid Member Paid Member

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    Fozzie, where are the 027 heads better than the 051?

    I've got an 027 on my old car, would it be best to get that one ported rather than the 9A head?
     
  14. prof Forum Addict

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    Gary

    with a full port job they mostly flow the same anyway, there is an old golf tuner that fozzie knows who always used the early heads and had great results, but i really don't think there is a lot in it.
     
  15. Fozzie_Bear Forum Member

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    As prof said after both being ported they will flow basically the same.
    With the 026/7 heads the inlet port has less restriction then the later heads. The divider is deaper down and nearly a third narrower, allowing the air to flow into it easier. As the air isn't being physically forced down then this is an advantage.
    The exhuast ports are shrouded more than the later heads, but, the gases are being forced from the chambers on this side so, although shrouded will still leave the chambers at a fair rate.
    John Jones(auddigolfhits) always seamed to use the earlier 026/7 heads and had very good results. I think his reasoning was that the inlets ports needed little work to get them flowing good(less material to remove over a shorter length), which is benefitial as they are more awkward to work on.
    The exhaust ports, where the gases leave under pressure can then be narrowed and fettled.
    The port angles will still need to be smoothed and reduced on both heads.
    I've seen another companies work with heads, which was VW Motorsport, again they used an early head, but fairplay, their workmanship was incredible!! Only problem was that the head came without the cam caps and the oil return hole was missing from the casting!!?? Very odd!
     
  16. kevh Forum Member

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    does the diferent casting in the combustion chamber make any difference? the mk3 head seemed to be angled and shaped differently in the combustion chamber as the 9a head resembles the kr head
     
  17. NormanCoal Forum Member

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    It wouldnt be the case as in the MK2 where you may have had either cast???

    I have a mk3 ABF in my MK2, but I havent looked at the cast as yet.

    I had an 027 cast on my KR, and once I had it flowed it certainly seemed to improve things
     
  18. Tubthumped Forum Junkie

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    Where does it give you the casting code?
     
  19. Fozzie_Bear Forum Member

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    You'll see it on the head, looking at the front on the top left hand corner.
    If heard that they've found the other casting on 2 litres, although they may have been from a corrado not a golf. My apologese [8(] .
     

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