This would be great to present to MSD to see what kind of rebuttal we would
get. Would you mind, Chris?
Ron
00 PB SLT QC 4X2 5.9 46RE 3.92 LSD
For modifications see my DML Profile (URL follows)
http://www.twistedbits.net/WWWProfile/dakota/Kw9pV1EkFeOYY
-----Original Message-----
From: owner-dakota-truck@buffnet.net
[mailto:owner-dakota-truck@buffnet.net]On Behalf Of chris@slowcar.net
Sent: Saturday, June 30, 2001 1:03 AM
To: dakota-truck@buffnet.net
Subject: Re: DML: Re: MSD
This is one of the things I never agreed with - 48k vs. 28k going farther,
etc.
Here's why:
There are 2 steps to "spark"
- First enough voltage must be developed across the spark plug gap to form a
plasma.
The voltage required to induce a plasma is not set by the spark module but
instead by
the external conditions of the spark gap. Specifically they are the
air/fuel ratio, amount
of H20 vapor and the cylinder pressure. The more humidity the lower the
plasma inducing
voltage. The higher the compression ratio (and thereby the pressure) the
higher the voltage.
I am unsure of the effect of varying air/fuel mixture, I assume it tracks
humidity
(dry gas = higher voltage)
- Second, after the plasma is formed, any excess voltage serves to breakdown
the plasma and
arcing occurs (the spark).
2.) The highest plasma inducing voltage required for motors operating with
14:1 compression
is less than 30kV. And no module can force the gap voltage to a higher
level. Once the plasma
breakdown voltage is exceeded the spark gap voltage drops by a factor of
~50x and the coil is
discharged with arcing across the gap.
3.) After the plasma breakdown, arcing (or spark) occurs. But the voltage at
which sustained
arcing occurs is about 1/50 the plasma inducing voltage.
Okay, so what does this mean?
Aftermarket ignition suppliers refer to the spark module's output voltage.
This is really meaningless.
The independent variable is not output voltage. Rather the independent
variable is the voltage
required to arc the plasma. Even if they say they can deliver 45kV, in a
11:0 compression motor,
25kV is all the module will ever deliver.
Chris Bennight
http://www.slowcar.net
66 Charger For Sale
http://www.slowcar.net/charger
----- Original Message -----
From: "Ronald Wong" <ron-wong@home.com>
To: <dakota-truck@BUFFNET.NET>
Sent: Saturday, June 30, 2001 2:18 AM
Subject: RE: DML: Re: MSD
| The difference between a standard MSD box and your standard ignition is a
| boost in primary voltage. Instead of 12-volts primary power being
| introduced to the coil, the MSD box boosts the voltage to 270-volts. On
an
| MSD Blaster SS coil I believe the 270 gets boosted to 48K-volts secondary.
| Std ignition and MSD Blaster coil nets about 28K-volts at the plugs. What
| does all this buy you? Better ignition and more complete combustion.
| That's why your gap can be opened up with an MSD box. 48K-volts can jump
| farther than 28K-volts.
|
| Ron
| 00 PB SLT QC 4X2 5.9 46RE 3.92 LSD
| For modifications see my DML Profile (URL follows)
| http://www.twistedbits.net/WWWProfile/dakota/Kw9pV1EkFeOYY
|
|
| -----Original Message-----
| From: owner-dakota-truck@BUFFNET.NET
| [mailto:owner-dakota-truck@BUFFNET.NET]On Behalf Of Sam South
| Sent: Friday, June 29, 2001 8:21 PM
| To: dakota-truck@BUFFNET.NET
| Subject: Re: DML: Re: MSD
|
|
| > Big difference (that may contribute to this) - '95 was OBD-I, '96+ is
| OBD-II
|
| That's what I'm inclined to believe also, the 98 had the MSD on from
around
| 10K until I sold it at 45K and bought the 95, it was on both trucks with
| fresh Mopar cap/rotors and Mopar/MSD wires, and also on the 95 I've used
| Accel and Mopar cap and rotor. With all these changes the only real
| difference I felt was with the MSD box itself. Maybe someone out there
could
| verify if there is some contributing factors in the OBD-I vs. the OBD-II
| systems.
| Sam South
| 95 Dak, 5.2L,3.90 LSD,5-speed(Soon to be 360 powered)
| 14.10@98.05
| http://www.twistedbits.net/WWWProfile/dakota/Mt5J8FaDfVCv6/
| http://people.mw.mediaone.net/sawcut64/home.html
|
| ----- Original Message -----
| From: "Andy Levy" <andylevy@yahoo.com>
| To: <dakota-truck-moderator@bent.twistedbits.net>
| Sent: Friday, June 29, 2001 10:36 PM
| Subject: Re: DML: Re: MSD
|
|
| > Sam South wrote on Friday 29 June 2001 09:43 pm:
| >
| > > I had one on my 98 3.9 and it "felt" stronger, but when it was
installed
| > > on my 95 5.2 it definitely felt like I lost a few ponies. I left it on
| > > anyway thinking maybe I was wrong about it, but after I saw with my
own
| > > eyes the difference it made on Mark Dak(I went with him that day to
the
| > > dyno) it's coming off and not going back on. Again I have nothing
| concrete
| > > to back this up with on my trucks other then how it "felt".
| > > Sam South
| > > 95 Dak, 5.2L,3.90 LSD,5-speed(Soon to be 360 powered)
| > > 14.10@98.05
| > > http://www.twistedbits.net/WWWProfile/dakota/Mt5J8FaDfVCv6/
| > > http://people.mw.mediaone.net/sawcut64/home.html
| > >
| > > ----- Original Message -----
| > > From: <Datstein@aol.com>
| > > To: <Dakota-truck@buffnet.net>
| > > Sent: Friday, June 29, 2001 8:29 PM
| > > Subject: DML: MSD
| > >
| > >
| > >> What gives? I'm saving my sheckles to buy an MSD 6A because of all
the
| > > good
| > >> talk on the DML and now it's robbing horsepower??? There must be
some
| > >> correlation between the other mods on the vehicle in question or
maybe
| > > it's
| > >> just the emotional justification that the buyer doesn't want to admit
| > >> that
| > >> he/she wasted $150. I for one would like to hear several
| > >> opinions...especially with dyno results. David
| > >
| > >
| >
| > --
| > -andy
| > andylevy@yahoo.com
| > http://home.twcny.rr.com/andylevy/dakota/
| > '99 CC 4x4 318 auto
|
|
|
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 12:01:56 EDT