[Diy_efi] Group buy changed to injector timing

jay zumwalt pjzum at yahoo.com
Sun Nov 17 05:02:19 GMT 2002


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Thanks to all of you who made suggestions. You have been great. I have more than enough info to run with, especially given that I have so much to learn. We are considering an ECU to make an engine run on hydrogen.
Thanks again for all of your help.
Jay Z (not the rapper)
 
 Dave Dahlgren <ddahlgren at snet.net> wrote:First I have worked with the DTA stuff and it was a nightmare at the least.
First there is only 1 tech guy for the entire world and he is in England so you
have some time zone issues. Second i thought the whole programing process not
very intuitive at all. Last even when you talk to the tech guy what he says
sounds like english but the words make no sense..

Injection timing, are you looking for the injector opening or closing point at
180 BTDC to TDC. I would assume the closing point. If we make the assumption
that effective airflow is about done at 0.050 valve lift then an injector 
closing point at this crank position is fairly realistic. But that would only be
true if the injector is at the valve face which it is not. This means you have
to add the transport time to the closing poi nt. It is pretty simple to measure
the distance from the injector to the face of the valve and to measure the cross
section of the port. With these two numbers you can first calculate the mean
airspeed at a given rpm and then calculate how many crank degrees it will take
for the fuel to get past the valve for that rpm. That is a starting point for
the value that the injector needs to close at. Of course there is some tuning to
do from there and if you change the injector phasing and have to take fuel away
in order to get the correct AFR then you are going in the correct direction. The
other thing that becomes obvious is that you need a phase map not just one fixed
point. Numbers for injector closing for a high performance / race engine sound
more like from 100 to 300 degrees BTDC depending on the above factors. Maybe
this is why you are having trouble with the range of closing points you are
seeking..

Dave Dahlgren

jay zumwalt wrote:
> 
> Thanks John I am familiar with some but not all. I will look at them. I have
> tried Pectel but the site "pectel" says it is under construction. How do I
> reach them?
> 
> Jay Z
> 
> Ioannis Andrianakis wrote:
> 
> Have a look at DTA P8 Pro at www.dtafast.co.uk
> It has very good value for money. You can set the injection start or
> end degrees BTDC. The Motec will allow more detail with different
> injection angles for different rpm and loads. Other ecus capable are
> the Autronic, Pectel and EFI and probably many other I am not aware
> of.
> Regards,
> John Andrianakis
> 
> ----- Original Message -----
> From: jay zumwalt
> To: diy_efi at diy-efi.org
> Sent: 11 Íïåìâñßïõ 2002 20:39
> Subject: Re: [Diy_efi] Group buy
> 
> Dave: This is unrelated to your post, I hope you dont
> mind. I am there to learn a little about efi. I don't have
> much to
> contribute. My application is a little out of the
> ordinary.
> 
> I have a question for you since your with a company that
> represents
> many suppliers of controllers. I am looking for a
> controller that allow me
> to move the fuel injection pulse to anywhere between 180
> deg BTDC to
> TDC. We have looked at many but most of the ones we have
> looked at do not move the injection pulse. We are settling
> on the MoTec 48 but wondered if there was anything any
> cheaper? Do you know anything about AEM Power? I sent them
> an email but they have not returned one. I am also
> starting to look at Accel.
> 
> Any help you or anyone else can provide would be much
> appreciated.
> 
> Thanks
> 
> Jay Zumwalt
> 
> 
>


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<P>Thanks to all of you who made suggestions. You have been great. I have more than enough info to run with, especially given that I have so much to learn. We are considering an ECU to make an engine run on hydrogen.
<P>Thanks again for all of your help.
<P>Jay Z (not the rapper)
<P>&nbsp;
<P>&nbsp;<B><I>Dave Dahlgren &lt;ddahlgren at snet.net&gt;</I></B> wrote:
<BLOCKQUOTE style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">First I have worked with the DTA stuff and it was a nightmare at the least.<BR>First there is only 1 tech guy for the entire world and he is in England so you<BR>have some time zone issues. Second i thought the whole programing process not<BR>very intuitive at all. Last even when you talk to the tech guy what he says<BR>sounds like english but the words make no sense..<BR><BR>Injection timing, are you looking for the injector opening or closing point at<BR>180 BTDC to TDC. I would assume the closing point. If we make the assumption<BR>that effective airflow is about done at 0.050 valve lift then an injector <BR>closing point at this crank position is fairly realistic. But that would only be<BR>true if the injector is at the valve face which it is not. This means you have<BR>to add the transport time to the closing poi nt. It is pretty simple to measure<BR>the distance from the injector to the face of the valve and to measure the cross<BR>section of the port. With these two numbers you can first calculate the mean<BR>airspeed at a given rpm and then calculate how many crank degrees it will take<BR>for the fuel to get past the valve for that rpm. That is a starting point for<BR>the value that the injector needs to close at. Of course there is some tuning to<BR>do from there and if you change the injector phasing and have to take fuel away<BR>in order to get the correct AFR then you are going in the correct direction. The<BR>other thing that becomes obvious is that you need a phase map not just one fixed<BR>point. Numbers for injector closing for a high performance / race engine sound<BR>more like from 100 to 300 degrees BTDC depending on the above factors. Maybe<BR>this is why you are having trouble with the range of closing points you are<BR>seeking..<BR><BR>Dave Dahlgren<BR><BR>jay zumwalt wrote:<BR>&gt; <BR>&gt; Thanks John I am familiar with some but not all. I will look at them. I have<BR>&gt; tried Pectel but the site "pectel" says it is under construction. How do I<BR>&gt; reach them?<BR>&gt; <BR>&gt; Jay Z<BR>&gt; <BR>&gt; Ioannis Andrianakis <EVOTECH at B-ONLINE.GR>wrote:<BR>&gt; <BR>&gt; Have a look at DTA P8 Pro at www.dtafast.co.uk<BR>&gt; It has very good value for money. You can set the injection start or<BR>&gt; end degrees BTDC. The Motec will allow more detail with different<BR>&gt; injection angles for different rpm and loads. Other ecus capable are<BR>&gt; the Autronic, Pectel and EFI and probably many other I am not aware<BR>&gt; of.<BR>&gt; Regards,<BR>&gt; John Andrianakis<BR>&gt; <BR>&gt; ----- Original Message -----<BR>&gt; From: jay zumwalt<BR>&gt; To: diy_efi at diy-efi.org<BR>&gt; Sent: 11 Íïåìâñßïõ 2002 20:39<BR>&gt; Subject: Re: [Diy_efi] Group buy<BR>&gt; <BR>&gt; Dave: This is unrelated to your post, I hope you dont<BR>&gt; mind. I am there to learn a little about efi. I don't have<BR>&gt; much to<BR>&gt; contribute. My application is a little out of the<BR>&gt; ordinary.<BR>&gt; <BR>&gt; I have a question for you since your with a company that<BR>&gt; represents<BR>&gt; many suppliers of controllers. I am looking for a<BR>&gt; controller that allow me<BR>&gt; to move the fuel injection pulse to anywhere between 180<BR>&gt; deg BTDC to<BR>&gt; TDC. We have looked at many but most of the ones we have<BR>&gt; looked at do not move the injection pulse. We are settling<BR>&gt; on the MoTec 48 but wondered if there was anything any<BR>&gt; cheaper? Do you know anything about AEM Power? I sent them<BR>&gt; an email but they have not returned one. I am also<BR>&gt; starting to look at Accel.<BR>&gt; <BR>&gt; Any help you or anyone else can provide would be much<BR>&gt; appreciated.<BR>&gt; <BR>&gt; Thanks<BR>&gt; <BR>&gt; Jay Zumwalt<BR>&gt; <BR>&gt; <BR>&gt;<BR><BR><BR>_______________________________________________<BR>Diy_efi mailing list<BR>Diy_efi at diy-efi.org<BR>http://www.diy-efi.org/mailman/listinfo/diy_efi</BLOCKQUOTE><p><br><hr size=1>Do you Yahoo!?<br>
<a href="http://rd.yahoo.com/hosting/mailsig/*http://webhosting.yahoo.com">Yahoo! Web Hosting</a> - Let the expert host your site
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