[Diy_efi] Group buy changed to injector timing

[Dave Dahlgren]

First I have worked with the DTA stuff and it was a nightmare at the leas=
t.
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 sa=
ys
sounds like english but the words make no sense..

Injection timing, are you looking for the injector opening or closing poi=
nt at
180 BTDC to TDC. I would assume the closing point. If we make the assumpt=
ion
that effective airflow is about done at 0.050 valve lift then an injector=
=20
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 m=
easure
the distance from the injector to the face of the valve and to measure th=
e cross
section of the port. With these two numbers you can first calculate the m=
ean
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 tu=
ning to
do from there and if you change the injector phasing and have to take fue=
l away
in order to get the correct AFR then you are going in the correct directi=
on. The
other thing that becomes obvious is that you need a phase map not just on=
e 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. Ma=
ybe
this is why you are having trouble with the range of closing points you a=
re
seeking..

Dave Dahlgren

jay zumwalt wrote:
>=20
> 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?
>=20
> Jay Z
>=20
>  Ioannis Andrianakis <evotech at b-online.gr> wrote:
>=20
>      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 a=
re
>      the Autronic, Pectel and EFI and probably many other I am not awar=
e
>      of.
>      Regards,
>      John Andrianakis
>=20
>           ----- Original Message -----
>           From: jay zumwalt
>           To: diy_efi at diy-efi.org
>           Sent: 11 =CD=EF=E5=EC=E2=F1=DF=EF=F5 2002 20:39
>           Subject: Re: [Diy_efi] Group buy
>=20
>           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.
>=20
>           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.
>=20
>           Any help you or anyone else can provide would be much
>           appreciated.
>=20
>           Thanks
>=20
>           Jay Zumwalt
>=20
>          =20
>


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