[Diy_efi] New to list, have questions
Daniel R. Nicoson
A6intruder at adelphia.net
Wed Jul 14 16:43:44 GMT 2004
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Bobby,
You have some choices. You can go with the resistor method or build a P & H
driver.
Basically with the resistor you are adding a resistor in series with each
injector to achieve the same 15 ohms resistance that your OEM injectors had.
So if your lo-impedance injectors are 4 ohms, you will need a resistor of
about 11 ohms. Keep in mind this resistor will have to carry almost an amp
of current so it needs to be capable of that load. I have "heard" that late
1980's Honda's used resistors like this. You might get lucky and find some
in a junk yard. (or check in on yahoo groups JYturbo and ask Joseph if he
has any he would sell cheap, he's a Honda guy).
The downside to the resistor method is that you will loose some response
time at idle and low power settings. Since you are restricting the current
flow through the low impedance injectors, they won't develop the same force
to snap open the injector as they were intended to do. If idle quality and
emissions are a concern you might have trouble without a proper P & H
injector driver.
For example, I run 30# injectors on my 1994 Mustang. It idles around 2-3ms
for the pulse width. If I had 60# injectors, I would only be idling around
1-1.5ms. It just so turns out that it takes all of 1.5 to 2.0 ms to open a
high impedance injector. A lo-impedance injector with a proper driver will
open in 1.5ms or less. So I could survive with reasonable idle with the
bigger injectors but not if I didn't use a proper driver. (the car would
obviously run, I would just have to compromise idle quality and possibly
emissions).
If you want to research and build your own P & H injector driver, go to
Digi-Key.com and search for the LM1949. This is a solenoid controller.
Pull down the data sheet, they have a typical circuit in there.
I do have a design I was going to post one of these days but I have another
project to finish in front of the lo-z driver board.
What power level are you trying to achieve? What size injectors do you
think you'll need? How are you tuning the computer, EEC Tuner or TwEECer?
Don't go any bigger than you need to on injectors.
Dan
-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org]On
Behalf Of Bobby C
Sent: Wednesday, July 14, 2004 1:53 AM
To: diy_efi at diy-efi.org
Subject: [Diy_efi] New to list, have questions
Hey, my name is Bobby. I am new to this list, and have a few question
that you guys, especially Ford gurus might have an answer for.
I am building a TT mustang and I want to upgrade to low impedance
injectors to meet my fuel demands. To do this with the a9l computer on my
mustang, i was told i had to wire up a resistor box. This resistor box can
be made from a few Radio Shack components, and beeing an avid diy'er, i want
to build it myself, and wire it myself into the stock ecu. Does anyone have
and links/info/parts numbers that they would be able to help me out with.
TIA
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<BODY bgColor=3D#ffffff>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2>Bobby,</FONT></SPAN></DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2>You=20
have some choices. You can go with the resistor method or build a =
P &=20
H driver. </FONT></SPAN></DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2>Basically with the resistor you are adding a resistor in series =
with each=20
injector to achieve the same 15 ohms resistance that your OEM injectors=20
had. So if your lo-impedanc</FONT></SPAN><SPAN=20
class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff size=3D2>e =
injectors are 4=20
ohms, you will need a resistor of about 11 ohms. Keep in mind this =
resistor will have to carry almost an amp of current so it needs to be =
capable=20
of that load. I have "heard" that late 1980's Honda's used =
resistors like=20
this. You might get lucky and find some in a junk yard. (or =
check in=20
on yahoo groups JYturbo and ask Joseph if he has any he would sell =
cheap, he's a=20
Honda guy).</FONT></SPAN></DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2>The=20
downside to the resistor method is that you will loose some response =
time at=20
idle and low power settings. Since you are restricting the current =
flow=20
through the low impedance injectors, they won't develop the same force =
to snap=20
open the injector as they were intended to do. If idle quality and =
emissions are a concern you might have trouble without a proper P & =
H=20
injector driver.</FONT></SPAN></DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2>For=20
example, I run 30# injectors on my 1994 Mustang. It idles around =
2-3ms for=20
the pulse width. If I had 60# injectors, I would only be idling =
around=20
1-1.5ms. It just so turns out that it takes all of 1.5 to 2.0 ms =
to open a=20
high impedance injector. A lo-impedance injector with a proper =
driver will=20
open in 1.5ms or less. So I could survive with reasonable idle =
with the=20
bigger injectors but not if I didn't use a proper driver. (the car =
would=20
obviously run, I would just have to compromise idle quality and possibly =
emissions).</FONT></SPAN></DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2>If you=20
want to research and build your own P & H injector driver, go to=20
Digi-Key.com and search for the LM1949. This is a solenoid=20
controller. Pull down the data sheet, they have a typical circuit =
in=20
there.</FONT></SPAN></DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2>I do=20
have a design I was going to post one of these days but I have another=20
project to finish in front of the lo-z driver =
board.</FONT></SPAN></DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2>What=20
power level are you trying to achieve? What size injectors do you =
think=20
you'll need? How are you tuning the computer, EEC Tuner or =
TwEECer? =20
Don't go any bigger than you need to on injectors.</FONT></SPAN></DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2>Dan</FONT></SPAN></DIV>
<DIV><SPAN class=3D871350616-14072004><FONT face=3DArial color=3D#0000ff =
size=3D2></FONT></SPAN> </DIV>
<BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
<DIV class=3DOutlookMessageHeader dir=3Dltr align=3Dleft><FONT =
face=3DTahoma=20
size=3D2>-----Original Message-----<BR><B>From:</B> =
diy_efi-bounces at diy-efi.org=20
[mailto:diy_efi-bounces at diy-efi.org]<B>On Behalf Of </B>Bobby=20
C<BR><B>Sent:</B> Wednesday, July 14, 2004 1:53 AM<BR><B>To:</B>=20
diy_efi at diy-efi.org<BR><B>Subject:</B> [Diy_efi] New to list, have=20
questions<BR><BR></FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Hey, my name is Bobby. I am new =
to this=20
list, and have a few question that you guys, especially Ford gurus =
might have=20
an answer for.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I am building a TT mustang and I want =
to upgrade=20
to low impedance injectors to meet my fuel demands. To do this =
with the=20
a9l computer on my mustang, i was told i had to wire up a resistor =
box. =20
This resistor box can be made from a few Radio Shack components, and =
beeing an=20
avid diy'er, i want to build it myself, and wire it myself into the =
stock=20
ecu. Does anyone have and links/info/parts numbers that they =
would be=20
able to help me out with. </FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial =
size=3D2>TIA</FONT></DIV></BLOCKQUOTE></BODY></HTML>
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