The larger exhaust valves only came in with the EF XR6 - the EB and ED XR6 have std valves. Higher compression pistons are also from the EF - std EF comp is 9.3:1 (and EF XR6 goes up to 9.34:1 with smaller chamber volumes) - on the EB and ED XR6 the compression was taken up to 9:1 from 8:8 by just reducing the volume of the combustion chambers (by shaving the head or with different head gasket or by different shaped casting I'm not sure).
On the EF they also went to a different crankshaft design which apparently is smoother than the earlier ones - but that different crank is common to all EF's, not just the XR6.
I've also heard all the XR6's were factory ballanced too - but not sure about that.
Edited to correct mistake with compression ratios.
2mm bigger exhaust valve and higher pressure fuel pump. Never knew anything about the hgiher compression and cam though. Is it a different cam or just has changed duration and lift due to bigger exhaust valves? All this for 7kw?
1999 AU XR8
14.594 @ 94.40mph
152.2RWKW (APS dyno)
Switchable Shift Kit, K&N panel filter, Lukey straight thru mufflers, momo gear and steer,
DBA slotted rotors/Bendix ultimate pads (front), Pioneer MP3 head unit and BA XR carpet mats.
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