On 02/06/2006, at 7:17 AM, WSpohn4@aol.com wrote:
>
> The normal step to take on these is to use flat top pistons (the
> normal ones
> are dished) which puts you into the 9.5 area - a useful bump but
> not enough
> to cause any problems running 92 octane.
>
My JE flat tops pushed my compression "over the top". With a ported,
polished, shaved (shampooed) head my compression has well passed the
11 stage and I can only really safely (especially under competition
conditions) run my engine on 105+ octane fuel (cheapest I can get is
AVGAS with is $1.00 litre cheaper than the cheapest ELF fuel). And
people complain about fuel prices - I pay almost DOUBLE what they do!
I can cruise the streets on "premium unleaded" @ 98 octane but she
pings badly if I have to accelerate rapidly (under load) - or get up
a decent sized hill.
Our "special permission" to use this leaded fuel is reviewed each
year with the constant threat that it will finally be banned from
track use under all sorts of environmental acts (don't get me started
about the leaded vs unleaded debate). The next review is September
this year. If AVGAS is banned then I will finally have to do
something about the head - and it has been suggested that there is
possibly some room to dish the pistons as well.
So there you go.
You want pistons? I highly recommend these people http://
www.jepistons.com/
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