<VV> Re: turbo distrubutor

[John]

You turbo guys need to solve the turbo distributor advance problem with
modern electonics.  You need "Megajolt Lite, Jr"!  MJLJ uses a RPM x MAP
(Manifold Pressure) table to configure the ignition advance, commanding
a Ford EDIS module to adjust the ignition advance based on the engine's
current runtime condition.  You can configure the distributor curve to
anything you want.  Take a look at:

<http://picasso.org/mjlj/>

Cost less than $100 bucks if you use junk yard parts.  No Ford jokes
please!  Ford sparks are as good as GM sparks.

John

> From: "Jim Burkhard" <burkhard@rochester.rr.com>
> To: <UltraMonzaWest@aol.com>, <VirtualVairs@corvair.org>
> Date: Fri, 23 Apr 2004 21:23:55 -0400
> Subject: <VV> turbo distrubutor
> 
> Bah!  You can't "eliminate" the need for vaccum advance UNLESS you are doing
> ALL full-throttle driving. Mechanical advance only is fine for a race car,
> but on anything that is driven anytime part throttle (including all streeted
> cars), you will be underadvanced and the throttle response & fuel economy
> will suck.  All spark ignited engines need to increase the spark advance at
> part throttle loads. There's no way around it. If you crank up the static or
> centrifal advance to (ahem) "compensate" for the lack of a vacuum advance,
> you will then be over-advanced at full load (prone to knock and/or losing
> torque from the optimal timing).
> 
> The fact that GM didn't have a V.A. on the turbo distributors was only
> because they were trying to keep the whole deal simple and having BOTH a
> pressure retard and vacuum advance would have made things more expensive.
> But one level of spark advance (reardless of load!) at all engine speeds up
> to 4,000 rpm (or is it 4400, I forget...) is no way to run an engine,
> though. No modern car dispenses with load-varied spark advance. Sure, it's
> all done electronically (no distributor), but the optimum spark advance
> ALWAYS varies a lot with load. No way around it whether a turbo engine or
> not...  To not do so means you lose part throttle torque (feels unresponsive
> and you have to go deeper into the throttle to make the car move) and also
> fuel economy (on account of a drop in indicated thermal efficiency from the
> mistimed combustion).
> 
> Jim Burkhard
> Air, Fuel, and that other one... Now what was it...?