On Thu, 2003-01-16 at 14:40, Kirk Hillman wrote:
>
> Okay, if Gasflowing = porting, then I suspect there are no specs one could
> give a local person to do the job is there? I was simply thinking that
> anyone could carefully smooth things out themselves (round sharp corners,
> etc.) but a good porting job is much different. If ACR and Turner have a
> 'system' it couldn't really be duplicated could it? While I know there are
> many shops around that will port my head they know about top end rather than
> keeping the power as low as possible. I have a spare head to play with...
> any suggestions?
Porting (Gasflowing) is all about transfering the maximum amount of
fuel-mixture into the chamber in the best possible condition, and
expelling it as efficiently as possible.
This is why ACR have a special exhaust section: it has no baffles and
the vent-pipe is bigger than normal - it all reduces the build-up of
pressure in the exhaust manifolds (note: you want *some* pressure, just
not much..)
It's also why good exhaust systems have fancy exhaust manifolds - to
make sure the exhaust distances are equal for all pistons (it's to do
with wave-propogation and stuff, apparently)
With the exhaust system, as smooth as possible means a faster flow, and
no eddies slowing things down.
On the inlet side, you want the inlet pipework to have the same length
for each piston; wou want the fuel/air mixture to be as vapourised as
possible (hence the slightly rough surface); and you want a carb that
can breath as much air as possible.
For top-end speed (and acceleration), you want all the components to be
light.
For bottom-end grunt, you want the maximum mass possible for the
flywheel, but light pistons & con-rods.
... oh, and you want everything to be perfectly balanced...
-- --==++ Ian Stuart: Edinburgh University Data Library.Information is not knowledge Knowledge is not wisdom Wisdom is not truth Truth is not beauty Beauty is not love Love is not music -- Mary.
Personal web site: http://lucas.ucs.ed.ac.uk/ _______________________________________________ LRO mailing list LRO@land-rover.team.net http://land-rover.team.net/mailman/listinfo/lro
This archive was generated by hypermail 2b30 : Thu Jan 16 2003 - 10:19:50 EST