> Is there any one who could help me? Also dose a crossflow head help
Please remember the phrase, "Make it breathe." That is the key to
power. Cross flow heads, a tuned header with non-restrictive exhaust,
individual intake runners tuned, of course and perhaps even a custom
FI system is how you get there.
Volumetric efficiency does come at a price, not counting the bits
you need. The price is that this kind of tuning both pushes the peak
of the HP and torque curves higher but also reduces the torque at
slower engine speeds. That's why race cars have 6 and 7 speed
gearboxes. The revs never need drop out of the power band. Low
speed drivability suffers. Everything, and I mean everything, is a
compromise.
I just designed a system for our rally car. Drivability at all
speeds
is paramount in that car. Low speed torque is also a must. For that
application, we chose a custom header and <almost> open exhaust
but stayed with the single carb. This allowed the exhaust gasses to
scavenge rather well but kept the hump in the torque curve lower
and broad. We then will use the gearbox to put us in the right
power range.
If I were designing a power plant for racing, I would consider first,
the maximum engine speed that the valve train and reciprocating
components would tolerate -- without damage. That would set the
'red line' to target in volumetric efficiency tuning. Investments
beyond
that would return very little, if any, return on your investment.
Two cents please.
best,
rick
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