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Re: BPW numbers
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Thanks for the info Dave,
This thing (now that I've got some other numbers)--runs at 154 BL at =
cruise. Idle is at 132 (close enough) ---so I'm assuming WOT is going to =
be pretty lean.=20
Here's some more specs...Cam duration 283 INT and 286 EXH, Intake lift =
is .435
and exhaust is .455. Compression ratio is 9.4 to 1 and the heads have =
been ported to match Vortec specs (this truck is a 1988). 3.42 ratio =
diff is what we're working with--and actually the truck peels around =
pretty good the way it is...we're just a little concerned about the lean =
ratio at cruise and WOT. I'll try adding 15% across the upper end of the =
fuel map to start with...
Lyndon.
-----Original Message-----
From: Dave Zug <dzug@delanet.com>
To: gmecm@diy-efi.org <gmecm@diy-efi.org>
Date: February 22, 2000 9:35 PM
Subject: Re: BPW numbers
=20
=20
On a MAF system, if you UP the fuel pressure 7 - 10 %, and set the =
flow rate to a value 7 - 10% higher, the 305 injectors will have the =
best chance on a un-hotrodded 350 motor IMO. you can add 20% more FP =
and mess up idle and cause BLM skewing, and the WOT will have more fuel, =
or you can leave the FP alone and idle will be great but WOT may have =
the injectors static and still have low o2 readings. Either is a =
comprimise. 305 to 350 =3D bit more than 14% more air, need 14% more =
fuel and thats with no other intake mods. If you were using 12ms at WOT =
on the 305 you'll use the same injectors 14% longer in the 350 - closer =
to static (or over)
=20
dont just change the BPW by 14%, (in a MAF) you'll do the opposite =
of what you are after. the injector base PW should be the actual setting =
for the injectors used - then you adjust it a bit for more FP.. which =
makes the injectors have a higher flow rate than they are "stamped". a =
better spray pattern too. On a TPI (not TBI) each of the 8 are rated at =
19#/hr for a 305 and 22#/hr for a 350. 19 * 1.14 =3D 21.66 amazingly... =
keeps the injectors below something like 80% of max duty cycle.
=20
and you're "off road" so no problem with the feds.
=20
Please anyone correct anything. I'm not a pro, I just play one on =
TV.
=20
PS - my soon to be dropped-in 383 will start out with 350 injectors. =
(MAF too).=20
----- Original Message -----=20
From: Programmer=20
To: gmecm@diy-efi.org=20
Sent: Tuesday, February 22, 2000 4:46 PM
Subject: BPW numbers
=20
=20
Greetings guys,
=20
Just wondering what BPW numbers would do when a guy changes a =
305 to a 350. The 1988 TBI injectors are different, PROM BPW numbers are =
148 for a 305 and 135 for a 350. This is based on flow in =
grams/sec...what would you have to set a 305 injector to, to work in a =
350 properly -- or is the flow rate too low already ?
=20
Lyndon.
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<DIV><FONT color=3D#000000 size=3D2>Thanks for the info =
Dave,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT><FONT size=3D2>This thing =
(now that I've=20
got some other numbers)--runs at 154 BL at cruise. Idle is at 132 (close =
enough)=20
---so I'm assuming WOT is going to be pretty lean. </FONT></DIV>
<DIV><FONT size=3D2>Here's some more specs...Cam duration 283 INT and =
286 EXH,=20
Intake lift is .435</FONT> </DIV>
<DIV><FONT size=3D2>and exhaust is .455. Compression ratio is 9.4 to 1 =
and the=20
heads have been ported to match Vortec specs (this truck is a 1988). =
3.42 ratio=20
diff is what we're working with--and actually the truck peels around =
pretty good=20
the way it is...we're just a little concerned about the lean ratio at =
cruise and=20
WOT. I'll try adding 15% across the upper end of the fuel map to start=20
with...</FONT> </DIV>
<DIV><FONT size=3D2></FONT> </DIV>
<DIV><FONT size=3D2>Lyndon.</FONT></DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 solid 2px; MARGIN-LEFT: 5px; PADDING-LEFT: =
5px">
<DIV><FONT face=3DArial size=3D2><B>-----Original =
Message-----</B><BR><B>From:=20
</B>Dave Zug <<A=20
href=3D"mailto:dzug@delanet.com";>dzug@delanet.com</A>><BR><B>To: =
</B><A=20
href=3D"mailto:gmecm@diy-efi.org";>gmecm@diy-efi.org</A> <<A=20
=
href=3D"mailto:gmecm@diy-efi.org";>gmecm@diy-efi.org</A>><BR><B>Date:=20
</B>February 22, 2000 9:35 PM<BR><B>Subject: </B>Re: BPW=20
numbers<BR><BR></DIV></FONT>
<DIV><FONT face=3DArial size=3D2>On a MAF system, if you UP the fuel =
pressure 7=20
- 10 %, and set the flow rate to a value 7 - 10% higher, the =
305=20
injectors will have the best chance on a un-hotrodded 350 motor =
IMO. =20
you can add 20% more FP and mess up idle and cause BLM skewing, and =
the WOT=20
will have more fuel, or you can leave the FP alone and idle will be =
great=20
but WOT may have the injectors static and still have low o2 =
readings. =20
Either is a comprimise. 305 to 350 =3D bit more than 14% more =
air, need=20
14% more fuel and thats with no other intake mods. If you were using =
12ms at=20
WOT on the 305 you'll use the same injectors 14% longer in the 350 - =
closer=20
to static (or over)</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>dont just change the BPW by 14%, =
(in a MAF)=20
you'll do the opposite of what you are after. the injector base PW =
should be=20
the actual setting for the injectors used - then you adjust it a bit =
for=20
more FP.. which makes the injectors have a higher flow rate than =
they are=20
"stamped". a better spray pattern too. On a TPI (not =
TBI)=20
each of the 8 are rated at 19#/hr for a 305 and 22#/hr for a 350. 19 =
* 1.14=20
=3D 21.66 amazingly... keeps the injectors below something like 80% =
of max=20
duty cycle.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>and you're "off road" so =
no problem=20
with the feds.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>Please anyone correct anything. I'm =
not a pro,=20
I just play one on TV.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>PS - my soon to be dropped-in 383 =
will start=20
out with 350 injectors. (MAF too). </FONT></DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 solid 2px; MARGIN-LEFT: 5px; =
MARGIN-RIGHT: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- =
</DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A href=3D"mailto:nwester@eidnet.org"=20
title=3Dnwester@eidnet.org>Programmer</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A=20
href=3D"mailto:gmecm@diy-efi.org"=20
title=3Dgmecm@diy-efi.org>gmecm@diy-efi.org</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Tuesday, February =
22, 2000=20
4:46 PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> BPW =
numbers</DIV>
<DIV><BR></DIV>
<DIV><FONT color=3D#000000 size=3D2>Greetings guys,</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000 size=3D2>Just wondering what BPW =
numbers would do=20
when a guy changes a 305 to a 350. The 1988 TBI injectors are =
different,=20
PROM BPW numbers are 148 for a 305 and 135 for </FONT><FONT=20
color=3D#000000 size=3D2>a 350. This is based on flow in =
grams/sec...what=20
would you have to set a 305 injector to, to work in a 350 =
properly -- or=20
is the flow rate too low already ?</FONT></DIV>
<DIV><FONT color=3D#000000 size=3D2></FONT> </DIV>
<DIV><FONT color=3D#000000=20
size=3D2>Lyndon.</FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>
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