3.8 engine conversion where to buy????
01-29-2007, 01:59 PM
#46
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Good point Geoff.
I believe the key to improved combustion efficiency lies in accurate squish control and is an area we have put a lot of work into. On my 3.8 race engine we used to run 12.5:1 on a stock chamber, with the 9m billet heads we squeezed it up to 12.8:1 on the same cam and fuel without an issue, only to then build an identical stroker version of the same engine at 4.0 litres which runs over 13:1, again on the same fuel. Interestingly the 4 litre engine will tolerate a +4 degree ignition sweep from optimum and does not detonate, such is the stability of combustion, which makes me think that we could try 14:1 at some point in the future.
I believe the key to improved combustion efficiency lies in accurate squish control and is an area we have put a lot of work into. On my 3.8 race engine we used to run 12.5:1 on a stock chamber, with the 9m billet heads we squeezed it up to 12.8:1 on the same cam and fuel without an issue, only to then build an identical stroker version of the same engine at 4.0 litres which runs over 13:1, again on the same fuel. Interestingly the 4 litre engine will tolerate a +4 degree ignition sweep from optimum and does not detonate, such is the stability of combustion, which makes me think that we could try 14:1 at some point in the future.
