> >>> Paul,
> >>> Here is some information from Tracy on the
coil
> problem.
> >>> Ian
> >>>
> >>> Coil/igniters are fairly critical on two
things.
> >>>
> >>> (1) Ambient temps around coils should be kept
> under 130 degrees when run
> >>> at constant high rpm operation. I enclose my
> coils and have a blast
> >>> tube blowing cool air into the enclosure to
> ensure this.
> >>>
> >>> (2) Dwell time on coil needs to be correct.
If
> possible, measure the
> >>> running dwell time on the coil (Pin A on RX8
> coils, see instructions for
> >>> location). It should be close to 3
> milliseconds. I can't remember the
> >>> details of your EC2 order but the Renesis
> version can be ordered with
> >>> one of two options, LS1 coils (5 millisecond
> dwell time) and RX-8 coils
> >>> (3 MS). If you have the wrong version the
coils
> could run hot (LS1
> >>> running on RX-8 coils) or have weak spark
(RX-8
> running on LS1 coils).
> >>>
> >>>
> >>> Ah so. Very good. All makes sense. Jibes with
> what I measured
> >>> on the RX8 car coils. I.E. 2.5 milliseconds.
> I'll start mounting
> >>> coils inside the ram air ducting for the
> radiators in my 3D's :)
> >>> Simple fix.
> >>>
> >>> Have you checked your dwell time yet Ian?
> >>>
> >>> Paul Lamar ...No rotor no motor.
> >>>
> >>
> >> Yes 2.5ms.
> >> I will send the cowl pictures soon.
> >> Ian
> >>
> >> I have come to the conclusion, after looking at
> the stock
> >> RX8 computer PC board, the required power
> switching transistors
> >> or FETs MUST be in the coils. Search as I might
I
> cannot find
> >> anything on the PC board that looks like a high
> current FET's or
> >> power transistors used for driving four coils.
> >>
> >> IMHO fuel injectors will soon have the power
> switch integrated into
> >> the injector body as well.
> >>
> >> Paul Lamar ...No rotor no motor.
> >>
> >
> > Paul
> >
> > What about the two transistors attached to the
> heat sink in the upper
> > left
> > of the board?
> >
> > DougFir
> >
> > I am not sure what they do. They might be the
> injector switch.
> > NEC B1453
> > 2SB1453 PNP epitaxial silicon power transistor
> > For fast switching.
> > Functions PNP epitaxial silicon power transistor
> > Applications For fast switching
> > Features High DC amplification factor
> > hFE>=100(VCE=-5V, IC=-0.5A)
> > Full-mold package, easy mounting
> > Performances VCBO=-60V, VCEO=-60V, VEBO=-7.0V
> > Ic(DC)=-3A, PT=25W(Tc=25deg.C)
> > PT=2.0W(Ta=25deg.C)
> > hFE=100 to 400(VCE=-5V, Ic=-0.5A)
> > VCE(sat)<=-1.0V(Ic=-3A, IB=-0.3A),
> > VBE(sat)<=-2.0V(Ic=-3A, IB=-0.3A)
> >
> >
> > Paul Lamar
> >
> > Those transistor could be a high speed switching
> power
> > supply that reduces the 12 volt car battery to 5
> volts
> > for the computer.
> >
> > BTW do any of you electronic types recognize
> > this semiconductor logo? An italic capital D
with
> a line
> > under it.
> > --
> > Paul Lamar ...No rotor no motor.
>
>
> Hi Paul,
> They would not use a switching power supply to
> convert 12 volts DC to 5
> volts DC.
> Switching power supplies are used for converting
AC
> to DC.
> They would use a voltage regulator of some sort.
> Possibly a Diode working in
> the reverse
> breakdown range of 5 volts. So that anything above
5
> volts would be clipped.
> My guess is that those transistors feed the coil
but
> without seeing the
> schematics I can't say for sure.
> A coil works by building a magnetic field by
> electrical current flowing
> through it's windings. when that
> flow is suddenly cut off, the magnetic field
> collapses and depending on the
> number of windings the original
> 12 volts is amplified by the number of turns of
wire
> in the coil creating
> the high voltage discharge across the
> spark plug, or igniter as they are referred to on
> this forum.
>
> Dan
>
> Dan, that coil switch you mentioned I am pretty
sure
> is in the coil and that is what is failing when
> we fire it twice as often as a piston engine
and/or
> over
> heat it.
>
> Switching power supplies are also used to reduce
14
> Volts
> to five volts as they are very efficient. Over 80%
> and as
> high as 95%. They only sample the 14 volts every
now
> and
> then and filter the resultant pulse train in large
> capacitors.
>
> Linear regulators like Zener diodes and analog
> single chip five
> volt regulators on the other hand are only about
35%
> efficient
> (5/14) so there is a lot of wasted power and a lot
> of heat
> generated. You must drop about 9 volts across the
> chip or a power
> resistor. At 3 amps that is 27 watts. No small
> amount.
>
> This RX8 PCM computer is probably drawing several
> amps out of the
> battery or about 15 watts or so.
>
> On the other hand these transistors could be used
as
> a transmitter
> ...transmitting your speed and vehicle ID to a
> receiver on the side of
> the road connected to a computer at the Highway
> Patrol office so
> they can automatically send you a speeding ticket
:)
> Also if your
> check engine light comes on the EPA can arrest you
> for polluting:)
>
> Now if there is a GPS chip in there and flash
memory
> as well they
> will know when and where and how fast you went for
> the last couple
> of years :)
>
> There are a couple of other power device on the
> board,
> K2114 and K3225 what ever they are. No heat sink
> however.
>
> Paul Lamar ...No rotor no motor.
Paul
Those pnp devices you are questioning would never
qualify for conventional ignition drivers with the
specs provided.
1. only a 60V rating where 400-500 is required(with
derating).
2. only a 3A rating where 10-15A is required (with
derating)
3. pnp devices aren't used as low side switches; an
npn or n chan fet is required.
They also are not suited to injector drives which
usually require 4A peak + derating and are usually
low
side switches.
regards, Robert
I did not think so. What do you think they are using
them
for? I hope not a transmitter. BTW do you know
anything
about the LowJack transmitter. Could this be it?
--
Paul Lamar ...No rotor no motor.
The only applications of power pnp devices in a +14v
system that comes to mind are high side switches or
linear regulator pass transistors. They may supply
switched power to the instrument panel or air bag
circuits. Try ohm metering from the +14V input to the
emitters and trace the collector connections?
regards, Robert
OK thanks
Paul Lamar ...No rotor no motor.
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