DIY_EFI Digest Tuesday, December 7 1999 Volume 04 : Number 681 In this issue: injectors and 02 sensors Re: Getting facts straight! (3/3) Re: injectors and 02 sensors Getting facts straight! (3/3) (EGO sensor function) Re: DIY_EFI Digest V4 #680 Re: DIY_EFI Digest V4 #680 Re: DIY_EFI Digest V4 #680 Remove me from this list please Remove me from this list please See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Tue, 07 Dec 1999 08:31:01 -0500 (EST) From: Andris Subject: injectors and 02 sensors On Tue, 7 Dec 1999, DIY_EFI Digest wrote: > I haven't seen any specification information that states what the maximum ON > time is for an injector before damage occurs and this is the data that actually > determines the extreme end of the duty cycle in the terms of maxium on time. 80% Duty cycle has been the rule of thumb for a while. You could (most likely, not scientific, just an educated assumption, please do not flame) run at 100% if you have fuel flowing, since the heat generated would be quickly conducted to the fuel. The problem tends to be repeatability above 80% but below 100% where the injector starts to close, and then re-opens when it hasn't fully closed yet. This is similar to the repeatability down low, around 1.7ms when you try to have short pulsewidths on big injectors for a not-insanely-rich idle. You tell the injector to open, and then tell it to close before it has fully opened... > > So do the EGO sensors work at stoich because they were designed to work at > this ratio, or is there something intrinsic about their operation and the > conditions at stoich that causes this? Catalytic converters were designed to run at stoich, so engines needed stoich back in the day of low-turbulence high volume heads to run cleanly for the cat. Sensors were generated to make this as easy/cheap to achieve as possible. > > I guess the OEM's wouldn't be using them if they didn't work at stoich, so it > doesn't really matter if it is easy to make them this way or not. A better > question would be are they cheaper than the wide band sensors because they are > easy to make, or because they are used on so many cars? Volume is a huge reason. The standard 02's are produced by the tens of millions, in is a commodity. The wide-band isn't as widely used, and if just one or two companies make it, well, there isn't price competition. Wide band needs a "black box" to go with it as well (which I don't know enough about). Speaking of which - did the wide-band 02 project ever get completed? It started when I was on the list the first time 2 years ago, and there hasn't been much in the DIY_EFI archives since then. Any info out there? Thanks! Andris/SPD Z28tt-89 IROC T56 DFI Twin Turbo ------------------------------ Date: Tue, 7 Dec 1999 08:40:14 -0500 From: "Bruce Plecan" Subject: Re: Getting facts straight! (3/3) - ----- Original Message ----- From: Tom Parker To: Greg Hermann Sent: Tuesday, December 07, 1999 5:26 AM Subject: Re: Getting facts straight! (3/3) I'll bet ya the primary driver for the cost is the warranty recovery rate. When the manufacturuer is picking up the tab, lots of ifs no longer matter. Switchin voltage does vary by fuel type, that I got from a fellow that does oem calibrations, also, shows why there is an option to change it in some calibrations, (ie allows for the very high alky content), in like Brazil. Grumpy | Greg Hermann wrote: | | >So--what are we left with that is magical about stoich? The facts that a | >stoich mixture is the point where a three way catalyst works best for | >cleaning up tailpipe emissions and that it is also the point where a | >standard EGO or HEGO exhaust oxygen sensor (as opposed to a UEGO WBO2 | >sensor) switches its output. Period. | | So do the EGO sensors work at stoich because they were designed to work at | this ratio, or is there something intrinsic about their operation and the | conditions at stoich that causes this? | | I guess the OEM's wouldn't be using them if they didn't work at stoich, so it | doesn't really matter if it is easy to make them this way or not. A better | question would be are they cheaper than the wide band sensors because they are | easy to make, or because they are used on so many cars? | | -- | Tom Parker - parkert@xxx.nz | - http://www.geocities.com/MotorCity/Track/8381/ | ------------------------------ Date: Tue, 7 Dec 1999 08:49:35 -0500 From: "Bruce Plecan" Subject: Re: injectors and 02 sensors - ----- Original Message ----- From: Andris To: Do It Yourself EFI list Sent: Tuesday, December 07, 1999 8:31 AM Subject: injectors and 02 sensors | On Tue, 7 Dec 1999, DIY_EFI Digest wrote: | > I haven't seen any specification information that states what the maximum ON | > time is for an injector before damage occurs and this is the data that actually | > determines the extreme end of the duty cycle in the terms of maxium on time. I've held them on for 45 mins with no detectable damage.. | 80% Duty cycle has been the rule of thumb for a while. You could (most | likely, not scientific, just an educated assumption, please do not | flame) run at 100% if you have fuel flowing, since the heat generated | would be quickly conducted to the fuel. The problem tends to be | repeatability above 80% but below 100% where the injector starts to close, | and then re-opens when it hasn't fully closed yet. This is similar to the | repeatability down low, around 1.7ms when you try to have short | pulsewidths on big injectors for a not-insanely-rich idle. You tell the | injector to open, and then tell it to close before it has fully opened... The above is obsolete from all I've seen, in the last year. The trick is the min off time that allows the injector to actually relax, and be predictable in it's openings. | > So do the EGO sensors work at stoich because they were designed to work at | > this ratio, or is there something intrinsic about their operation and the | > conditions at stoich that causes this? Just answered in another post. | Catalytic converters were designed to run at stoich, so engines needed | stoich back in the day of low-turbulence high volume heads to run cleanly | for the cat. Sensors were generated to make this as easy/cheap to achieve | as possible. No, no, no, the cats run at an average of slightly richer then Stoi, and never run steady state 14.7:1, unless by accident. | > I guess the OEM's wouldn't be using them if they didn't work at stoich, so it | > doesn't really matter if it is easy to make them this way or not. A better | > question would be are they cheaper than the wide band sensors because they are | > easy to make, or because they are used on so many cars? | | Volume is a huge reason. The standard 02's are produced by the tens of | millions, in is a commodity. The wide-band isn't as widely used, and if | just one or two companies make it, well, there isn't price | competition. Wide band needs a "black box" to go with it as well (which I | don't know enough about). Speaking of which - did the wide-band 02 project | ever get completed? It started when I was on the list the first time 2 | years ago, and there hasn't been much in the DIY_EFI archives since | then. Any info out there? Thanks! Gar is still a work in progess on it, and several others from time to time are still working with various ideas, about them. Grumpy | | Andris/SPD | Z28tt-89 IROC T56 DFI Twin Turbo | ------------------------------ Date: Tue, 7 Dec 1999 07:37:38 -0700 From: bearbvd@xxx.net (Greg Hermann) Subject: Getting facts straight! (3/3) (EGO sensor function) >So do the EGO sensors work at stoich because they were designed to work at >this ratio, or is there something intrinsic about their operation and the >conditions at stoich that causes this? It is an intrinsic part of their operation. Basically--they detect the presence or absence of oxygen in the exhaust gas stream, and they do so in pretty much a switch fashion. This is the basic basic physics/physical chemistry of a Zr O2 cell. BTW--this type of cell was in use on stack gasses from large stationary boilers and the like for decades before they came into use for automotive apps--at a _MUCH_higher price, of course! > . A better >question would be are they cheaper than the wide band sensors because they are >easy to make, or because they are used on so many cars? Both. A UEGO (WBO2 sensor actually has a HEGO included as part of it, and also has an ion "pumping" chamber as well). Naturally, higher production rates would bring down the price. Greg ------------------------------ Date: Tue, 7 Dec 1999 07:52:41 -0700 From: bearbvd@xxx.net (Greg Hermann) Subject: Re: DIY_EFI Digest V4 #680 >I haven't seen any specification information that states what the maximum ON >time is for an injector before damage occurs and this is the data that actually >determines the extreme end of the duty cycle in the terms of maxium on time. >After all, if the duty cycle were restricted to one turn of an engine then at >600RPM I have, with 80% duty cycle, a possible pulse width of 80ms which >is far >higher than the 12.8ms that I am currently restricting my injector too. I would say that 80 or 85% is a good maximum duty cycle--at ANY engine speed, for the cooling reason, and also just to leave a bit of head room at the top end. 2 ms minimum on time and 2 ms minimum off time, again at any engine speed, is a decent rule of thumb to avoid fuel delivery inconsistencies. > > >As an aside, to add my own urban legend, I've run the Honda injectors >for more >than an hour at 6600RPM (without fuel) in the open air using a 12.8ms >pulse rate >and 73% duty cycle. At the end of an hour the injectors are certainly hot to >touch but not so hot as to burn and certainly not as hot as I would assume the >area above the intake valve is on an engine at 6600RPM. I have't tried running >them with fuel for an hour but I would imagine that they would run cooler. > >The stumble only occurs when the throttle is snapped open as fast as possible. >Normally on aircraft this isn't a good idea but on a hovercraft I could >see some >yahoo doing this. When the stumble occurs the O2 sensor goes off the scale in >the lean direction so I assume that I should probably make the maxium pulse >width RPM dependant so if the throttle is snapped open at idle, like an >accelerator pump, I should give the injector a 40ms pulse (80% duty cycle at >1200RPM) or so every engine revolution. Are you saying that you have written your program to restrict the injectors to 12.8 ms on time, regardless of engine speed?? If this is the case, and you are getting the correct mixture at 6000 rpm, it is virtually a sure thing that you are going to be lean at the torque peak (4500rpm??) . The torque peak will always require a longer on time than the HP peak (more fuel is needed PER revolution at the torque peak than anywhere else). (I know, not quite true if the maximum bmep and maximum friction loss torque do not occur at exactly the same engine speed. If you are programming in a maximum injector on time of 12.8 ms, I would bet that this is the source of the lean transition. The nature of the load curve for the hovercraft (fan, I presume?) is HP increasing with the cube of the rpm--so--the lean problem MAY only be rearing its head on a transition, only because you do not have enough steady state load available at the torque peak to create the full fuel/air demand that the engine is capable of at that engine speed. Greg ------------------------------ Date: Tue, 7 Dec 1999 07:55:27 -0700 From: bearbvd@xxx.net (Greg Hermann) Subject: Re: DIY_EFI Digest V4 #680 >>Hi John et al, >> >> >>...but an engine cycle is 720 degrees and therefore, at 7000RPM, with >>an 80% duty cycle the max pw is 13.7ms. >> >>Yes John your quite right a 4 stroke IC engine has a working cycle >>that >>encompasses 720 degrees of crank. On the other hand an Injector is >>not any IC engine and has a duty cycle that is of one revolution only. >> >>This does of course give rise to the question... are you only >>injecting every second revolution of the engine ? If so that may >>establish part of the reason for the stumble you are experiencing. >> >>Phil >> Injecting only every other revolution is, in fact, pretty typical procedure for sequential port injection systems. Greg ------------------------------ Date: Tue, 7 Dec 1999 09:34:24 -0500 From: "Gary Derian" Subject: Re: DIY_EFI Digest V4 #680 > So do the EGO sensors work at stoich because they were designed to work at > this ratio, or is there something intrinsic about their operation and the > conditions at stoich that causes this? EGO sensors output when there is oxygen only on one side (rich) and have no output when there is oxygen on both sides (lean) This characteristic is intrinsic. A 3 way cat also works best right at this point. Engine design and tuning is optimized to make the cats work well. Without cats, lean for cruise and rich for power would be the way to go. Gary Derian ------------------------------ Date: Tue, 7 Dec 1999 10:34:52 -0500 From: "Patrick Anglum" Subject: Remove me from this list please This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. - ------_=_NextPart_001_01BF40C8.A329CEEA Content-Type: text/plain; charset="iso-8859-1" Patrick Anglum Passport 4400 Development 4100 Guardian Street M/S NE Simi Valley, CA 93063-3397 panglum@xxx.com > % (805) 577-2288 > % ESN 495-2288 > > > > -----Original Message----- > From: DIY_EFI-Digest-Owner@xxx.edu > [SMTP:DIY_EFI-Digest-Owner@xxx.edu] > Sent: Sunday, December 05, 1999 12:00 PM > To: DIY_EFI-Digest@xxx.edu > Subject: DIY_EFI Digest V4 #677 > > > DIY_EFI Digest Sunday, December 5 1999 Volume 04 : Number > 677 > > > > In this issue: > > Re: Ref. Signal off of AMC I6 > mem-cal > Add-on systems which affect output pulse width? > > See the end of the digest for information on subscribing to the > DIY_EFI or DIY_EFI-Digest mailing lists. > > ---------------------------------------------------------------------- > > Date: Sun, 05 Dec 1999 09:32:45 -0500 > From: Shannen Durphey > Subject: Re: Ref. Signal off of AMC I6 > > > > > Date: Sun, 5 Dec 1999 00:56:23 -0500 (EST) > > From: Mike Comai > > Subject: Ref. Signal off of AMC I6 > > > > I am currently trying to get my first major retrofit up and running. I > > have everything installed and when I try to start it the injector's > don't > > fire. I was told that I need a filter on the negative side of the coil > > and to feed the filtered signal into the Reference line on the ECM > (which > > I am using a '747). I was given a design for a filter which looks like > > this: > > 5K 10K > > Coil -----/\/\/\/---------/\/\/\/\------------ ECM > > | | > > ----- ----- > > ----- 15uf -----100pf > > | | > > gnd gnd > > > > From a mechanic's point of view, (and because there's little other > info to work with) why haven't you adapted a GM ignition module to the > AMC dizzy? The voltage on the negative side of the coil "bounces" > after the plug fires, and your ecm may be getting what it thinks are > several reference pulses when it should get one. 'Course this is a > rough guess.... you might try to get a scan tool and watch rpm > readings during cranking to verify this. Another possibility is that > everything is ok but your calibration is wrong, or your injectors are > wrong, or the coil isn't firing because the reference line is > grounding out the signal from the dizzy. > > Also, if you're running the reference line from the distributor, do > you have the est line connected? Where? One of the great benefits of > using an ecm is computer controlled spark. Without it, you're not > realizing the full potential of your project. > Shannen > > > When the filter is in place, the injector don't fire. When I remove the > > filter and connect the coil directly to the ecm it appears to flood out > > the engine :( If someone could explain what voltages levels and shapes > are > > present on the neg. side of the coil and what it needs to get > conditioned > > to for the ECM that would be great too. Appreciate any help yall could > > give. > > > > Mike Comai > > '79 CJ5 > > > > ------------------------------ > > > > End of DIY_EFI Digest V4 #676 > > ***************************** > > > > To subscribe to DIY_EFI-Digest, send the command: > > > > subscribe diy_efi-digest > > > > in the body of a message to "Majordomo@xxx. > > > > A non-digest (direct mail) version of this list is also available; to > > subscribe to that instead, replace "diy_efi-digest" in the command > > above with "diy_efi". > > ------------------------------ > > Date: Sun, 5 Dec 1999 10:33:21 -0700 > From: cwagner@xxx.net > Subject: mem-cal > > Does anyone have any sugestions on what memcal I could get for > running a 4 cyl engine using a 747 computer? Or could I make one > out of some spare resistors. > > ------------------------------ > > Date: Sun, 05 Dec 1999 11:43:02 -0800 > From: "Andrew Brownsword" > Subject: Add-on systems which affect output pulse width? > > Hello again, > > After posting my project description yesterday I spent some time surfing > the web for add-on computers. All the systems I have seen so far seem to > work their magic by modifying the airflow meter's voltage input to the > ECU. > The ECU is then relied on to "do the right thing". > > It seems to me that this could be problematic if the ECU was designed to > expect a particular voltage range and the stock airflow meter generated > that > full range ... in other words there is no buffer for going beyond the > expected range of values. This seems fairly reasonable for an N/A engine > since it is extremely unlikely that the car will have to deal with >1 > atmosphere. > > It seems pretty obvious that most add-on computers are designed to > modify > input because it is easy. The computer reads one voltage, maps it through > a > table, and outputs another voltage. > > The alternative is to modify the ECU's output, which is a time dependant > pulse width. It simply isn't possible to have full remapping control over > the output because by the time you know what the pulse width is, the time > at > which you have to send it to the injectors has passed. It occurred to me > this morning, however, that an add-on computer could fairly easily extend > (not shorten) the pulse width based on input from a pressure sensor. It > would read its own MAP sensor to determine the amount of "extra" fuel > needed > beyond the amount the stock ECU has calculated (being tuned for where the > ECU's airflow meter saturates), detect the trailing edge of the ECU's > pulse, > and keep the pulse going for that extra time. > > So am I off my rocker here? Is this possible? Has anybody built a > product which does this? Is this even an issue, or does a stock ECU > program > ALWAYS allow enough buffer that input modification is a better approach? > > I hope I'm not reiterating common questions or wandering too far from > the > list charter -- I haven't seen a FAQ for this list yet, so please bear > with > me. And if there is a FAQ, you somebody point me at it? > > Cheers, > Andrew > > ------------------------------ > > End of DIY_EFI Digest V4 #677 > ***************************** > > To subscribe to DIY_EFI-Digest, send the command: > > subscribe diy_efi-digest > > in the body of a message to "Majordomo@xxx. > > A non-digest (direct mail) version of this list is also available; to > subscribe to that instead, replace "diy_efi-digest" in the command > above with "diy_efi". > - ------_=_NextPart_001_01BF40C8.A329CEEA Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Remove me from this list please


Patrick = Anglum
Passport 4400 Development
4100 Guardian Street  M/S = NE
Simi Valley, CA 93063-3397
panglum@xxx.com
% (805) 577-2288 
%  ESN 495-2288



    -----Original Message-----
    From:   DIY_EFI-Digest-Owner@xxx.edu = [SMTP:DIY_EFI-Digest-Owner@xxx.edu]
    Sent:   Sunday, December 05, 1999 12:00 PM
    To:     DIY_EFI-Digest@xxx.edu
    Subject:       = DIY_EFI Digest V4 #677


    DIY_EFI = Digest        Sunday, December 5 = 1999        Volume 04 : Number = 677



    In this issue:

            Re: Ref. Signal off of AMC I6
            mem-cal
            Add-on systems which affect output pulse width?

    See the end of the digest for = information on subscribing to the
    DIY_EFI or DIY_EFI-Digest mailing = lists.

    ---------------------------------------------------------= - -------------

    Date: Sun, 05 Dec 1999 09:32:45 = - -0500
    From: Shannen Durphey = <shannen@xxx.com>
    Subject: Re: Ref. Signal off of AMC = I6

    >
    > Date: Sun, 5 Dec 1999 00:56:23 = - -0500 (EST)
    > From: Mike Comai = <comai@xxx.edu>
    > Subject: Ref. Signal off of AMC = I6
    >
    > I am currently trying to get my = first major retrofit up and running.  I
    > have everything installed and = when I try to start it the injector's don't
    > fire.  I was told that I = need a filter on the negative side of the coil
    > and to feed the filtered signal = into the Reference line on the ECM (which
    > I am using a '747).  I was = given a design for a filter which looks like
    > this:
    >         = ;       = 5K           &nbs= p;   10K
    > Coil    = - -----/\/\/\/---------/\/\/\/\------------ ECM
    >     &nbs= p;           &nbs= p;       = |            = ;   |
    >         = ;            = ;  = - -----           = - -----
    >         = ;            = ;  ----- 15uf      -----100pf
    >         = ;            = ;    = |            = ;   |
    >         = ;            = ;   = gnd           &nb= sp; gnd
    >

    From a mechanic's point of view, (and = because there's little other
    info to work with) why haven't you = adapted a GM ignition module to the
    AMC dizzy?  The voltage on the = negative side of the coil "bounces"
    after the plug fires, and your ecm = may be getting what it thinks are
    several reference pulses when it = should get one.  'Course this is a
    rough guess.... you might try to get = a scan tool and watch rpm
    readings during cranking to verify = this.  Another possibility is that
    everything is ok but your calibration = is wrong, or your injectors are
    wrong, or the coil isn't firing = because the reference line is
    grounding out the signal from the = dizzy.

    Also, if you're running the reference = line from the distributor, do
    you have the est line = connected?  Where?  One of the great benefits of
    using an ecm is computer controlled = spark.  Without it, you're not
    realizing the full potential of your = project.
    Shannen

    > When the filter is in place, the = injector don't fire.  When I remove the
    > filter and connect the coil = directly to the ecm it appears to flood out
    > the engine :( If someone could = explain what voltages levels and shapes are
    > present on the neg. side of the = coil and what it needs to get conditioned
    > to for the ECM that would be = great too.  Appreciate any help yall could
    > give.
    >
    > Mike Comai
    > '79 CJ5
    >
    > = - ------------------------------
    >
    > End of DIY_EFI Digest V4 = #676
    > = *****************************
    >
    > To subscribe to DIY_EFI-Digest, s= end the command:
    >
    >     = subscribe diy_efi-digest
    >
    > in the body of a message to = "Majordomo@xxx.
    >
    > A non-digest (direct mail) = version of this list is also available; to
    > subscribe to that instead, = replace "diy_efi-digest" in the command
    >  above with = "diy_efi".

    ------------------------------

    Date: Sun, 5 Dec 1999 10:33:21 = - -0700
    From: cwagner@xxx.net
    Subject: mem-cal

    Does anyone have any sugestions on = what memcal I could get for
    running a 4 cyl engine using a 747 = computer?  Or could I make one
    out of some spare resistors.

    ------------------------------

    Date: Sun, 05 Dec 1999 11:43:02 = - -0800
    From: "Andrew Brownsword" = <asword@xxx.net>
    Subject: Add-on systems which affect = output pulse width?

    Hello again,

      After posting my project = description yesterday I spent some time surfing
    the web for add-on computers.  = All the systems I have seen so far seem to
    work their magic by modifying the = airflow meter's voltage input to the ECU.
    The ECU is then relied on to "do = the right thing".

      It seems to me that this could = be problematic if the ECU was designed to
    expect a particular voltage range and = the stock airflow meter generated that
    full range ... in other words there = is no buffer for going beyond the
    expected range of values.  This = seems fairly reasonable for an N/A engine
    since it is extremely unlikely that = the car will have to deal with >1
    atmosphere.

      It seems pretty obvious that = most add-on computers are designed to modify
    input because it is easy.  The = computer reads one voltage, maps it through a
    table, and outputs another = voltage.

      The alternative is to modify = the ECU's output, which is a time dependant
    pulse width.  It simply isn't = possible to have full remapping control over
    the output because by the time you = know what the pulse width is, the time at
    which you have to send it to the = injectors has passed.  It occurred to me
    this morning, however, that an add-on = computer could fairly easily extend
    (not shorten) the pulse width based = on input from a pressure sensor.  It
    would read its own MAP sensor to = determine the amount of "extra" fuel needed
    beyond the amount the stock ECU has = calculated (being tuned for where the
    ECU's airflow meter saturates), = detect the trailing edge of the ECU's pulse,
    and keep the pulse going for that = extra time.

      So am I off my rocker = here?  Is this possible?  Has anybody built a
    product which does this?  Is = this even an issue, or does a stock ECU program
    ALWAYS allow enough buffer that input = modification is a better approach?

      I hope I'm not reiterating = common questions or wandering too far from the
    list charter -- I haven't seen a FAQ = for this list yet, so please bear with
    me.  And if there is a FAQ, you = somebody point me at it?

    Cheers,
       Andrew

    ------------------------------

    End of DIY_EFI Digest V4 #677
    *****************************

    To subscribe to DIY_EFI-Digest, send = the command:

        subscribe = diy_efi-digest

    in the body of a message to = "Majordomo@xxx. 

    A non-digest (direct mail) version of = this list is also available; to
    subscribe to that instead, replace = "diy_efi-digest" in the command
     above with = "diy_efi".

- ------_=_NextPart_001_01BF40C8.A329CEEA-- ------------------------------ Date: Tue, 7 Dec 1999 10:34:35 -0500 From: "Patrick Anglum" Subject: Remove me from this list please This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. - ------_=_NextPart_001_01BF40C8.93F46ED0 Content-Type: text/plain; charset="iso-8859-1" Patrick Anglum Passport 4400 Development 4100 Guardian Street M/S NE Simi Valley, CA 93063-3397 panglum@xxx.com > % (805) 577-2288 > % ESN 495-2288 > > > > -----Original Message----- > From: DIY_EFI-Digest-Owner@xxx.edu > [SMTP:DIY_EFI-Digest-Owner@xxx.edu] > Sent: Monday, December 06, 1999 2:00 AM > To: DIY_EFI-Digest@xxx.edu > Subject: DIY_EFI Digest V4 #678 > > > DIY_EFI Digest Monday, December 6 1999 Volume 04 : Number > 678 > > > > In this issue: > > Getting facts straight!! (2/2) > Re: Signal of AMC 16 > Re: DIY_EFI Digest V4 #672 > re: Add-on systems which affect output pulse width? > > See the end of the digest for information on subscribing to the > DIY_EFI or DIY_EFI-Digest mailing lists. > > ---------------------------------------------------------------------- > > Date: Sun, 5 Dec 1999 16:17:59 -0700 > From: bearbvd@xxx.net (Greg Hermann) > Subject: Getting facts straight!! (2/2) > > (continued from 1/2) > > I have no hard numbers to back up this contention, YET, but I suspect that > if a port injected engine had MUCH BETTER fuel atomization than is > attainable with current art injectors, and a much quicker fuel squirt--one > timed with the high velocity flow of air in the port--that it would not > only make more power AND have a lower BSFC at WOT conditions, but would > ALSO want a mixture somewhat RICHER of stoich for maximum power than is > the > case with current art port injected engines! WHY?? evaporatin fuel on the > back side of a hot intake valve allows fuel vapor to displace > air--reducing > output, whereas--getting finely atomized fuel into the cylinder, and not > vaporizing much of it 'til after the I valve has closed not only avoids > displacement of inlet air by fuel vapor, but takes full advantage of the > heat absorbtion effect (as detailed above) during the compression stroke. > - ------------------------------------------ > > As to the best ECONOMY mixture--going lean of stoich tends to insure > burning every last bit of the fuel, and thus improves economy. The limit > is > usually when one approaches a lean misfire condition. (Misfires waste > fuel.) Better fuel atomization and distribution BOTH work to push this > limit further out. Also--the basic Otto cycle efficiency, even at WOT, > improves with a leaner mixture. Good chamber geometry and good mixture > turbulence during combustion push the lean limit further out, as well as > allowing better efficiency through higher compression ratio (by avoiding > pre-ignition and/or detonation). Furthermore-- leaner mixtures at part > throttle (with a spark ignition engine) reduce pumping losses, improving > economy even further at part throttle. SO--how far lean of stoich is best > for economy--the answer is--"As far as you can get away with!"--not some > set rule! It all depends on a large number of engine design factors. > > So--what are we left with that is magical about stoich? The facts that a > stoich mixture is the point where a three way catalyst works best for > cleaning up tailpipe emissions and that it is also the point where a > standard EGO or HEGO exhaust oxygen sensor (as opposed to a UEGO WBO2 > sensor) switches its output. Period. > > In closing--I would like to say that this list will return to far better > health once it finally get put onto a different server, and can FINALLY > get > off of the #$%^^&^*& digest mode--too many of the really knowlegeable > people here have been driven into the lurk mode by the digest format! > > AND--the trick to getting good information off of the internet is the same > as it is anywhere else in life--one has to learn to sort useful > information > out from BS!! There are always plenty of people in any field who are > willing to spread BS indiscriminately, usually without knowing any better, > but sometimes with premeditation and for profit! Good, old fashioned > fundamental education taken together with the ability and experience with > applying it is one of the most effective tools for accomplishing this > sorting process! > > Unfortunately, high performance engines seem to attract more than their > proportionate share of the BS and the profiteers (particularly the ones > who > feed on ignorance)! > > Although I am NOT going to be so bold as to say where, I WILL promise that > there is a bunch of good information in this last series of posts--it's up > to all of you to figure out where! > > Back to lurk mode, at least 'til we are off digest mode! > > Regards, Greg > > ------------------------------ > > Date: Mon, 6 Dec 1999 10:01:24 +0800 > From: dzorde@xxx.com > Subject: Re: Signal of AMC 16 > > Mike, I had a similar problem trying to interface my Chev HEI to the > aftermarket > ECU, made the car undrivable as it saw multiple crossovers of the same > trigger. > Try something along the lines of. > > 0.1uF 1k > coil ------||------/\/\/\/\/---------|--------------ECU > < > > 1k > > > | > ---- 15V zener > diode > 5W > /\ > | > gnd > regards > > Dan dzorde@xxx.com > > > > > Date: Sun, 5 Dec 1999 00:56:23 -0500 (EST) > From: Mike Comai > Subject: Ref. Signal off of AMC I6 > > I am currently trying to get my first major retrofit up and running. I > have everything installed and when I try to start it the injector's don't > fire. I was told that I need a filter on the negative side of the coil > and to feed the filtered signal into the Reference line on the ECM (which > I am using a '747). I was given a design for a filter which looks like > this: > > ------------------------------ > > Date: Mon, 6 Dec 1999 10:14:04 +0800 > From: dzorde@xxx.com > Subject: Re: DIY_EFI Digest V4 #672 > > I'm doing this on my current s/c set-up (although car is not yet > driveable), > anyway a blow off valve just venting of the air during idle and light > cruise. > Put your foot down, the valve shuts and there is instant 17psi boost. > Unlike a > turbo, you don't get a pop when it opens, but more of a constant whistle > as it > lets a lot of air out unless wot. > > Due to the extremely hot air (currently don't have an intercooler yet) I'm > reluctant to recirculate it through the intake filter (but due to the very > loud > whistle created by all this air veing vented in the engine bay I need to > do > something). Can anyone see a problem with feeding the air from the blow > off > valve into the exhaust system before the muffler and quieten it down this > way. > The line could be fed in at 45deg angle with the exhaust flow. > > Dan dzorde@xxx.com > > > Date: Thu, 2 Dec 1999 19:02:36 -0500 > From: "Jonathan Davis" > Subject: Re: KLUTCH!!! > > Another way to do this, perhaps would be a large bypass valve that > recirculates > any boost until WOT. Something like that would be intoxicating to drive - > nice > fat kick in the pants at WOT... > > ------------------------------ > > Date: Mon, 06 Dec 1999 02:19:16 -0500 > From: Chris Conlon > Subject: re: Add-on systems which affect output pulse width? > > "Andrew Brownsword" wrote: > > > It seems to me that this could be problematic if the ECU was designed > to > >expect a particular voltage range and the stock airflow meter generated > that > >full range ... in other words there is no buffer for going beyond the > >expected range of values. This seems fairly reasonable for an N/A engine > >since it is extremely unlikely that the car will have to deal with >1 > >atmosphere. > > I'm not going to get into this, really. You may very well run > into problems, especially with ignition timing, when you try to > trick an NA ECU into running much boost. (If you aren't > reprogramming it, that is.) > > > The alternative is to modify the ECU's output, which is a time > dependant > >pulse width. It simply isn't possible to have full remapping control > over > >the output because by the time you know what the pulse width is, the time > at > >which you have to send it to the injectors has passed. It occurred to me > > You can get very close, though, and very easily, in at least a > couple different ways. This presumes you're running injectors a > good bit larger than stock and will not need to lengthen the > pulse. Take your basic HC11. Wire a switch (power mosfet most > likely) in series with each injector drive circuit, watch for > voltage drops, ground ref, etc. Control each switch via output > compare line. Also wire up input compare lines so they can > detect when the ECU is *trying* to fire the injector, > independent of your switch's position. (If you have more than > 4 independent injector drive circuits, see 68332 instead.) Now > you can easily read RPM and load, more or less, via input > compares. You have a map, and for each rpm/pulse width point, > look up a new pulse width. (Or just multiply by old injector > size / new injector size, correct for short PW, etc etc.) > Leave each output compare line (switches) on, until the ecu > fires that circuit. You'll get an interrupt and time count > via input compare. Calculate how long you want the pulse to > be, program output compare to turn off at that time. When IC > turns off again, take another interrupt, turn OC back on. > > You can update RPM and desired-PW info at each injector firing > if desired. It is "behind reality" but not by much. Issues > exist with p&h drivers, need a dummy load, etc, or just supply > your own drivers. (Assorted details omitted, none too tricky.) > > I already have to do this (and more besides) for my semi > insane supercharged MR2 project, ugh. Lucky for me the ECU > already understands boost, timing retard, knock sensing, > etc, it just needs a few white lies about airflow & injector > sizes. > > > Now I had some questions for you, since you seem to know > Ford/Mazda stuff well. I did some searching for answers > but got confused and set it aside. I'd like to get an > MX-3 v6, and do some engine swapping. I've heard that a > 2.5l v6 from the MX-6 (or 626?) will basically drop in. > Wasn't there a 2.5l *turbo* Ford Probe GT engine at one > point? If so would it drop in w/o much work? Basically I > think the MX-3 is cute and would get one if I knew I could > grab a decent turbo engine (well, a whole front cut) from > something and drop it in pretty easily. (Ignoring ECU hassles > of course, got to have some fun!) I know there are aftermarket > turbo kits, etc, but I was hoping for a factory turbo motor. > Am I just real wrong or was there such a beast? I'm pretty > sure there was a not-common MX-6 turbo... comments? Thoughts? > > TIA, > Chris C. > > ------------------------------ > > End of DIY_EFI Digest V4 #678 > ***************************** > > To subscribe to DIY_EFI-Digest, send the command: > > subscribe diy_efi-digest > > in the body of a message to "Majordomo@xxx. > > A non-digest (direct mail) version of this list is also available; to > subscribe to that instead, replace "diy_efi-digest" in the command > above with "diy_efi". > - ------_=_NextPart_001_01BF40C8.93F46ED0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Remove me from this list please


Patrick = Anglum
Passport 4400 Development
4100 Guardian Street  M/S = NE
Simi Valley, CA 93063-3397
panglum@xxx.com
% (805) 577-2288 
%  ESN 495-2288



    -----Original Message-----
    From:   DIY_EFI-Digest-Owner@xxx.edu = [SMTP:DIY_EFI-Digest-Owner@xxx.edu]
    Sent:   Monday, December 06, 1999 2:00 AM
    To:     DIY_EFI-Digest@xxx.edu
    Subject:       = DIY_EFI Digest V4 #678


    DIY_EFI = Digest        Monday, December 6 = 1999        Volume 04 : Number = 678



    In this issue:

            Getting facts straight!! (2/2)
            Re: Signal of AMC 16
            Re: DIY_EFI Digest V4 #672
            re: Add-on systems which affect output pulse = width?

    See the end of the digest for = information on subscribing to the
    DIY_EFI or DIY_EFI-Digest mailing = lists.

    ---------------------------------------------------------= - -------------

    Date: Sun, 5 Dec 1999 16:17:59 = - -0700
    From: bearbvd@xxx.net (Greg = Hermann)
    Subject: Getting facts straight!! = (2/2)

    (continued from 1/2)

    I have no hard numbers to back up this = contention, YET, but I suspect that
    if a port injected engine had MUCH = BETTER fuel atomization than is
    attainable with current art = injectors, and a much quicker fuel squirt--one
    timed with the high velocity flow of = air in the port--that it would not
    only make more power AND have a lower = BSFC at WOT conditions, but would
    ALSO want a mixture somewhat RICHER = of stoich for maximum power than is the
    case with current art port injected = engines! WHY?? evaporatin fuel on the
    back side of a hot intake valve = allows fuel vapor to displace air--reducing
    output, whereas--getting finely = atomized fuel into the cylinder, and not
    vaporizing much of it 'til after the = I valve has closed not only avoids
    displacement of inlet air by fuel = vapor, but takes full advantage of the
    heat absorbtion effect (as detailed = above) during the compression stroke.
    - = - ------------------------------------------

    As to the best ECONOMY mixture--going = lean of stoich tends to insure
    burning every last bit of the fuel, = and thus improves economy. The limit is
    usually when one approaches a lean = misfire condition. (Misfires waste
    fuel.) Better fuel atomization and = distribution BOTH work to push this
    limit further out. Also--the = basic  Otto cycle efficiency, even at WOT,
    improves with a leaner mixture. Good = chamber geometry and good mixture
    turbulence during combustion push the = lean limit further out, as well as
    allowing better efficiency through = higher compression ratio (by avoiding
    pre-ignition and/or detonation). = Furthermore-- leaner mixtures at part
    throttle (with a spark ignition = engine) reduce pumping losses, improving
    economy even further at part = throttle. SO--how far lean of stoich is best
    for economy--the answer is--"As = far as you can get away with!"--not some
    set rule! It all depends on a large = number of engine design factors.

    So--what are we left with that is = magical about stoich? The facts that a
    stoich mixture is the point where a = three way catalyst works best for
    cleaning up tailpipe emissions and = that it is also the point where a
    standard EGO or HEGO exhaust oxygen = sensor (as opposed to a UEGO WBO2
    sensor) switches its output. = Period.

    In closing--I would like to say that = this list will return to far better
    health once it finally get put onto a = different server, and can FINALLY get
    off of the #$%^^&^*& digest = mode--too many of the really knowlegeable
    people here have been driven into the = lurk mode by the digest format!

    AND--the trick to getting good = information off of the internet is the same
    as it is anywhere else in life--one = has to learn to sort useful information
    out from BS!! There are always plenty = of people in any field who are
    willing to spread BS = indiscriminately, usually without knowing any better,
    but sometimes with premeditation and = for profit! Good, old fashioned
    fundamental education taken together = with the ability and experience with
    applying it is one of the most = effective tools for accomplishing this
    sorting process!

    Unfortunately, high performance = engines seem to attract more than their
    proportionate share of the BS and the = profiteers (particularly the ones who
    feed on ignorance)!

    Although I am NOT going to be so bold = as to say where, I WILL promise that
    there is a bunch of good information = in this last series of posts--it's up
    to all of you to figure out = where!

    Back to lurk mode, at least 'til we = are off digest mode!

    Regards, Greg

    ------------------------------

    Date: Mon, 6 Dec 1999 10:01:24 = +0800
    From: dzorde@xxx.com
    Subject: Re: Signal of AMC 16

    Mike, I had a similar problem trying = to interface my Chev HEI to the aftermarket
    ECU, made the car undrivable as it = saw multiple crossovers of the same trigger.
    Try something along the lines = of.

             &nb= sp;          = 0.1uF    1k
    coil       = - ------||------/\/\/\/\/---------|--------------ECU
             &nb= sp;           &nb= sp;           &nb= sp;           &nb= sp;            = <
             &nb= sp;           &nb= sp;           &nb= sp;           &nb= sp;            = >  1k
             &nb= sp;           &nb= sp;           &nb= sp;           &nb= sp;            = >
             &nb= sp;           &nb= sp;           &nb= sp;           &nb= sp;            = |
             &nb= sp;           &nb= sp;           &nb= sp;           &nb= sp;          = - ----   15V zener diode
    5W
             &nb= sp;           &nb= sp;           &nb= sp;           &nb= sp;            = /\
             &nb= sp;           &nb= sp;           &nb= sp;           &nb= sp;           &nb= sp; |
             &nb= sp;           &nb= sp;           &nb= sp;           &nb= sp;           = gnd
    regards

    Dan  dzorde@xxx.com




    Date: Sun, 5 Dec 1999 00:56:23 -0500 = (EST)
    From: Mike Comai = <comai@xxx.edu>
    Subject: Ref. Signal off of AMC = I6

    I am currently trying to get my first = major retrofit up and running.  I
    have everything installed and when I = try to start it the injector's don't
    fire.  I was told that I need a = filter on the negative side of the coil
    and to feed the filtered signal into = the Reference line on the ECM (which
    I am using a '747).  I was given = a design for a filter which looks like
    this:

    ------------------------------

    Date: Mon, 6 Dec 1999 10:14:04 = +0800
    From: dzorde@xxx.com
    Subject: Re: DIY_EFI Digest V4 = #672

    I'm doing this on my current s/c = set-up (although car is not yet driveable),
    anyway a blow off valve just venting = of the air during idle and light cruise.
    Put your foot down, the valve shuts = and there is instant 17psi boost.  Unlike a
    turbo, you don't get a pop when it = opens, but more of a constant whistle as it
    lets a lot of air out unless = wot.

    Due to the extremely hot air = (currently don't have an intercooler yet) I'm
    reluctant to recirculate it through = the intake filter (but due to the very loud
    whistle created by all this air veing = vented in the engine bay I need to do
    something).  Can anyone see a = problem with feeding the air from the blow off
    valve into the exhaust system before = the muffler and quieten it down this way.
    The line could be fed in at 45deg = angle with the exhaust flow.

    Dan  dzorde@xxx.com


    Date: Thu, 2 Dec 1999 19:02:36 = - -0500
    From: "Jonathan Davis" = <jfd125@xxx.edu>
    Subject: Re: KLUTCH!!!

    Another way to do this, perhaps would = be a  large bypass valve that recirculates
    any boost until WOT.  Something = like that would be intoxicating to drive -  nice
    fat kick in the pants at = WOT...

    ------------------------------

    Date: Mon, 06 Dec 1999 02:19:16 = - -0500
    From: Chris Conlon = <synchris@xxx.net>
    Subject: re: Add-on systems which = affect output pulse width?

    "Andrew Brownsword" = <asword@xxx.net> wrote:

    >  It seems to me that this = could be problematic if the ECU was designed to
    >expect a particular voltage range = and the stock airflow meter generated that
    >full range ... in other words = there is no buffer for going beyond the
    >expected range of values.  = This seems fairly reasonable for an N/A engine
    >since it is extremely unlikely = that the car will have to deal with >1
    >atmosphere.

    I'm not going to get into this, = really. You may very well run
    into problems, especially with = ignition timing, when you try to
    trick an NA ECU into running much = boost. (If you aren't
    reprogramming it, that is.)

    >  The alternative is to = modify the ECU's output, which is a time dependant
    >pulse width.  It simply = isn't possible to have full remapping control over
    >the output because by the time = you know what the pulse width is, the time at
    >which you have to send it to the = injectors has passed.  It occurred to me

    You can get very close, though, and = very easily, in at least a
    couple different ways. This presumes = you're running injectors a
    good bit larger than stock and will = not need to lengthen the
    pulse. Take your basic HC11. Wire a = switch (power mosfet most
    likely) in series with each injector = drive circuit, watch for
    voltage drops, ground ref, etc. = Control each switch via output
    compare line. Also wire up input = compare lines so they can
    detect when the ECU is *trying* to = fire the injector,
    independent of your switch's = position. (If you have more than
    4 independent injector drive = circuits, see 68332 instead.) Now
    you can easily read RPM and load, = more or less, via input
    compares. You have a map, and for = each rpm/pulse width point,
    look up a new pulse width. (Or just = multiply by old injector
    size / new injector size, correct for = short PW, etc etc.)
    Leave each output compare line = (switches) on, until the ecu
    fires that circuit. You'll get an = interrupt and time count
    via input compare. Calculate how long = you want the pulse to
    be, program output compare to turn = off at that time. When IC
    turns off again, take another = interrupt, turn OC back on.

    You can update RPM and desired-PW info = at each injector firing
    if desired. It is "behind = reality" but not by much. Issues
    exist with p&h drivers, need a = dummy load, etc, or just supply
    your own drivers. (Assorted details = omitted, none too tricky.) 

    I already have to do this (and more = besides) for my semi
    insane supercharged MR2 project, ugh. = Lucky for me the ECU
    already understands boost, timing = retard, knock sensing,
    etc, it just needs a few white lies = about airflow & injector
    sizes.


    Now I had some questions for you, = since you seem to know
    Ford/Mazda stuff well. I did some = searching for answers
    but got confused and set it aside. = I'd like to get an
    MX-3 v6, and do some engine swapping. = I've heard that a
    2.5l v6 from the MX-6 (or 626?) will = basically drop in.
    Wasn't there a 2.5l *turbo* Ford = Probe GT engine at one
    point? If so would it drop in w/o = much work? Basically I
    think the MX-3 is cute and would get = one if I knew I could
    grab a decent turbo engine (well, a = whole front cut) from
    something and drop it in pretty = easily. (Ignoring ECU hassles
    of course, got to have some fun!) I = know there are aftermarket
    turbo kits, etc, but I was hoping for = a factory turbo motor.
    Am I just real wrong or was there = such a beast? I'm pretty
    sure there was a not-common MX-6 = turbo... comments? Thoughts?

       TIA,
       Chris C.

    ------------------------------

    End of DIY_EFI Digest V4 #678
    *****************************

    To subscribe to DIY_EFI-Digest, send = the command:

        subscribe = diy_efi-digest

    in the body of a message to = "Majordomo@xxx. 

    A non-digest (direct mail) version of = this list is also available; to
    subscribe to that instead, replace = "diy_efi-digest" in the command
     above with = "diy_efi".

- ------_=_NextPart_001_01BF40C8.93F46ED0-- ------------------------------ End of DIY_EFI Digest V4 #681 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. A non-digest (direct mail) version of this list is also available; to subscribe to that instead, replace "diy_efi-digest" in the command above with "diy_efi".