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Location:
melb
Registered:
May 2002
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4ag 86kw v 100kw pistons
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Sun, 13 October 2002 01:46
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can anyone explain the differences between the two in terms of compression.
I want to use a 100kw block/pistons under a 86kw head and are wondering if I will get the same compression(10.3 - 1) as a 100kw gets.
or is there a differnece in capacity between the bigport and small port head.
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Location:
Melbourne
Registered:
May 2002
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Re: 4ag 86kw v 100kw pistons
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Mon, 14 October 2002 22:38
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chris,
firstly, the 100kw motor is not actually 10.3:1 cr, it is actually about 9.8:1. we put a 100kw bottom end under a big port head on a aw11 - it ran much better than it should have!!
the port sizes are different (obviously) - the combustion chambers are the same
T
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Location:
sydney
Registered:
May 2002
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Re: 4ag 86kw v 100kw pistons
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Mon, 14 October 2002 22:41
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toby,
when you did this was it just a straight swap, leaving all else the same... i have a 100kw bottom end sittin out back and was thinkin of doin this, do you recommend it?
cheers
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Location:
Sydney
Registered:
May 2002
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Re: 4ag 86kw v 100kw pistons
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Tue, 15 October 2002 04:37
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I currently run this configuration at the moment,
and my understanding so far that it is higher compression to run the 100 KW bottom end due to the shape of the piston.
ill take some photos taday but there is distinct differences between the pistons, and there may even be a third piston which is a really high compression piston similar to that of TODA racing pistons which have a compression of 11:1 (which i just fractured one of in my engine  )
the centre of these pistons raises a little more .The ACL replacement 100KW does not raise up that far, and the 86KW pistons do not raise up at all and in fact are recessed completely. I would be interested in a pick of someone elses 100KW factory pistons to see if there is any difference.
But basically it is a straight bottom end swap and everything lines up.
Ben
AE86 Trueno 4AGE
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I supported Toymods
Location:
melbourne.victoria.austra...
Registered:
June 2002
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