All the EST

[Ed Lansinger]

> Now please don't get me wrong, but what is the point of going so ape over an
> EST.  Top fuelers are using Magnetos and runnin' fours.  I see all kind of
> rails at Bandimere speedway (1/4 mile track) that have either stock
> electronic or minimumly modified ignition and the're runnin' sevens.  My
> point is why spend the time, effort and money to design something that won't
> do better that what is out there (cost and performance).  I'm not tryin' to
> be a pessimist, but can someone show me actual quicker quarter mile times or
> dyno tests.

Part of this argument is predicated on the assumption that the absence of EST
in Top Fuel drag racing is because it's not the best thing.  As I understand it,
EST is specifically disallowed there, so we really don't know if EST is worse
or no better for this application than the systems mentioned.  My guess is that
this is yet another attempt by the sanctioning bodies to "control costs"
or "keep things competitive" as we have seen in many (too many?) other
series.  (I suspect that this viewpoint results from marketing being
influenced by technical ignorance or prejudice.)

I read an article once (don't remember the source) about the ignition systems
used in Top Fuel.  One team spent $50,000 just to get reliable spark delivery
and timing.  The engineer they hired used special materials for the points and
rigged a system to flood the system with CO2 during the run, presumably to
reduce pitting or perhaps to allow higher voltages.

Reliable high speed ignition is tough enough in a normal engine and must be
many times tougher in Top Fuel.  You probably need enourmous spark energies
at those boost levels and insane air/fuel ratios.  It's really
tough to get such energies out of traditional mechanical systems due to
inherent limitations.  It seems much easier to get these energies
out of modern electronic systems.

Maybe you don't need varying spark advance, but it seems to me you need
consistent advance.  With bouncing points and torsional vibrations in a
distributor, this becomes a problem; not insoluble, just tough.  EST would
solve that problem easily.  Plus, I don't think one should so casually
ignore the initial 0.5 second when engine speed is changing; maybe
you could pick up another 0.05 there by having a flexible and more
accurate advance system.  That could win a championship.

Just another guess, but I'm wondering if the reason RPM (and thus horsepower)
isn't higher in Top Fuel engines is in part due to an RPM limitation
of the ignition system.  Again, something easily solved with EST.

Ideal spark advance as well as spark energy in normal engines varies with
manifold pressure and fuel/air ratio.  Although the combustion process
with nitromethane is quite different, I'll bet there are parallels.
In a Top Fuel dragster, you have manifold pressure variations as the
engine spins up and as you get more ram-air at higher speeds.  You also
get air/fuel variations due to the acceleration throwing the fuel and air
toward the rear cylinders, which also changes over the course of the run.
I think the situation is a lot less steady-state than it initially appears.
EST would be a nice way to take care of these things.

Having some intelligence on board could really help things, I would think.  You've
only got something like 2,000-2,500 cylinder firings during the run, so every one
better count.  Just thinking off the top of my head, you could do some nice
misfire detection, at least for diagnostic purposes.  Maybe you could have
an advanced misfire recovery algorithm, like do a flood clear on the
next revolution so you can recover sooner.  There's no reason a properly
controlled system should be spraying streams of nitrous out the pipes, as you
see quite frequently.

Weather conditions change over the course of a day, and if you could account for
some of this automatically and accurately you'd have an advantage.

The Holy Grail is, of course, traction control, which was tried (sorry I'm
forgetting which team) and was so successful it was banned.  So now
I understand they achieve largely the same thing by a pneumatically
operated progressive clutch that limits delivered torque by a pre-programmed
series of clutch plate engagements.  Pneumatic or electronic, it's still a
computer executing an algorithm, so I don't know why it is allowed and a
microcontroller you would find on any new car isn't.

If you haven't guessed by now, I have *no* experience with Top Fuel, so
please feel free to correct me as necessary.

Ed Lansinger
GM Powertrain Premium V (Northstar/Aurora) Software & Calibration Group