[Diy_efi] Sequential fire setup
mazak
rroberts2 at charter.net
Tue Aug 6 08:40:55 GMT 2002
This is a multi-part message in MIME format.
------=_NextPart_000_002E_01C23CFA.90230560
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Since I'm like really new here I hope this is the proper way to reply to =
my original message.
I guess my first post was a bit misleading & incomplete............
First, we already have everything bought-------fabricated intake =
matched to cnc'd big chief heads, throttle bodies, ecm, injectors, pump, =
etc.
When we started this car all we had was an empty building------we even =
made our stainless headers so doing the efi ourselves is very important.
Time isn't really an issue for our learning curve but we don't want to =
learn while the engine is on the dyno, not to mention doing something =
stupid & leaning the engine out.
Our dyno guy doesn't know squat about efi so it's totally up to us.
We do have a nice data acquisition setup so we can monitor the egt's =
once we're done with the dyno.
Here are some more specifics.......
Hopefully, we'll be in the 175-185 mph range & about 7.30 ET.
Our fuel pump can handle whatever we throw at it----------MagnaFlow =
electric gear type pump-----mondo you might say.......
88lb injectors. I don't have the flow numbers here with me.
The hood scoop is the newest pro-stock design & has a triangular =
opening---the isolator pan is ramped in the front & radiused in the back =
to force the air into the throttle bodies. We made the front ramp a =
little larger than normal since the tops of the throttle bodies are on a =
flat plane & cover a broader area than carburetors.
The intake manifold is fabricated aluminum sheet metal with each runner =
tapering down to match the cnc'd head intake port. Each runner is about =
6 inches long. The injector port angle is about 30 degrees from parallel =
to the intake runner.
The heads have 2.450 intake valves but I'm not sure about the exhaust & =
I don't know what cfm the heads flow (14 degree big chief's).
We don't know the exact compression ratio either but I'm guessing around =
14.5-15:1
Bore =3D 4.600in Stroke =3D4.25in
I guess I made a stupid assumption about injector angle since the intake =
is already made. By injector angle I meant at what degree before TDC do =
you fire the injector ? I realize it mainly depends on the grind of the =
cam so maybe I should ask at what point do you fire the injector in =
relation to the intake valve rising off it's seat ?
About the open/closed loop question I asked.......
We plan on running some in the Top Sportsman class which is merely a =
bracket race once you qualify. Maximum HP isn't a necessity in this =
class. Consistency is an absolute must so I was wondering if using a =
closed loop (even if the engine is rich) would provide some advantage =
over carbureted engines due to changing atmospheric conditions.
Also, we'll be able to electronically shift the transmission in this =
class so the only variables other than the engine will be track & =
atmospheric conditions. I just don't have a clue as to how fast the ecm =
reads the O=B2 sensor & adjusts the fuel .
Any thoughts on this ?
I'm in the process of making a decision about the cam position sensor. =
IMO it would be better to have a large ring with 2 magnets (exactly 180 =
apart) on the crankshaft rather than a small ring with 1 magnet on the =
camshaft. I have no idea how accurate the ecm or magnetic pick-ups are. =
The crank trigger for the ignition is about 8-9 inches & I'm guessing =
that the cam position sensor is every bit as critical as the timing ?
I can provide pics of the intake set-up & hood scoop we have if anyone =
is interested.
Thanks to everyone for their input !!!!!!
----- Original Message -----=20
From: mazak=20
To: diy_efi at diy-efi.org=20
Sent: Friday, August 02, 2002 1:04 PM
Subject: Sequential fire setup
Hello
After much thought my best friend & I have decided to put sequential =
fire EFI on our drag car.=20
I found this---> http://yarchive.net/car/fuel_injection.html
Very nice information---I learned more from this than anything else =
I've read.
We've already built a 91 Corvette drag car with a L98 TPI (batch fire) =
& had a little success. The owner didn't want to dyno the engine so =
everything has been a hit-or-miss considering our limited knowledge of =
EFI. We're fully aware of the basic theory & operation but since I read =
the post about sequential fire I've begun to wonder if there's any =
advantage over batch or bank fire.=20
Here's what we're planning......
The car will weigh 2250-2350lbs & we're hoping for 1200hp @8500rpm =
from our 565 BBC.=20
The throttle bodies (4) each have 2 two inch holes located directly =
over the fabricated intake runners.
The injectors we're starting out with are 88lb & the ecm is a FAST =
sequential fire. (http://www.fuelairspark.com/)
I guess I'm asking any of your personal opinions of this since you =
seem to have full knowledge of EFI systems.
It seems everyone we've spoken with so far gives us vague =
information-----for example: What injector angle ? How much fuel =
pressure ? What is the optimum EGT ? Open or closed loop if the engine =
is only run at WOT ?
I've got some general ideas about the answers to these questions but =
no rock-solid advice.
We would gladly compensate the right person that would work closely =
with us to get maximum HP.
Weeks could be spent on the dyno without some sort of baseline =
information.
Also, any tips or links to other online information & articles would =
be greatly appreciated.
Anyone interested in helping please contact me asap.
Thanks in advance
Ray Roberts
------=_NextPart_000_002E_01C23CFA.90230560
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content=3D"text/html; charset=3Diso-8859-1" =
http-equiv=3DContent-Type>
<META content=3D"MSHTML 5.00.3315.2870" name=3DGENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DArial size=3D2>
<DIV><FONT face=3DArial size=3D2>
<DIV>Since I'm like really new here I hope this is the proper way to =
reply to my=20
original message.</DIV>
<DIV> </DIV>
<DIV>I guess my first post was a bit misleading &=20
incomplete............</DIV>
<DIV> </DIV>
<DIV>First, we already have everything bought-------fabricated =
intake=20
matched to cnc'd big chief heads, throttle bodies, ecm, injectors, pump, =
etc.</DIV>
<DIV>When we started this car all we had was an empty building------we =
even made=20
our stainless headers so doing the efi ourselves is very =
important.</DIV>
<DIV>Time isn't really an issue for our learning curve but we don't want =
to learn while the engine is on the dyno, not to mention doing =
something=20
stupid & leaning the engine out.</DIV>
<DIV>Our dyno guy doesn't know squat about efi so it's totally up to =
us.</DIV>
<DIV>We do have a nice data acquisition setup so we can monitor the =
egt's once=20
we're done with the dyno.</DIV>
<DIV> </DIV>
<DIV>Here are some more specifics.......</DIV>
<DIV> </DIV>
<DIV>
<DIV>Hopefully, we'll be in the 175-185 mph range & about 7.30 =
ET.</DIV>
<DIV> </DIV></DIV>
<DIV>Our fuel pump can handle whatever we throw at it----------MagnaFlow =
electric gear type pump-----mondo you might say.......</DIV>
<DIV> </DIV>
<DIV>88lb injectors. I don't have the flow numbers here with =
me.</DIV>
<DIV> </DIV>
<DIV>The hood scoop is the newest pro-stock design & has a =
triangular=20
opening---the isolator pan is ramped in the front & radiused in the =
back to=20
force the air into the throttle bodies. We made the front ramp a =
little=20
larger than normal since the tops of the throttle bodies are on a flat =
plane=20
& cover a broader area than carburetors.</DIV>
<DIV> </DIV>
<DIV>The intake manifold is fabricated aluminum sheet metal with =
each=20
runner tapering down to match the cnc'd head intake port. Each runner is =
about 6 inches long. The injector port angle is about 30 degrees =
from=20
parallel to the intake runner.</DIV>
<DIV> </DIV>
<DIV>The heads have 2.450 intake valves but I'm not sure about the =
exhaust=20
& I don't know what cfm the heads flow (14 degree big =
chief's).</DIV>
<DIV> </DIV>
<DIV>We don't know the exact compression ratio either but I'm guessing =
around=20
14.5-15:1</DIV>
<DIV> </DIV>
<DIV>Bore =3D 4.600in Stroke =3D4.25in</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>I guess I made a stupid assumption about injector angle since the =
intake is=20
already made. By injector angle I meant at what degree before TDC do you =
fire=20
the injector ? I realize it mainly depends on the grind of the cam so =
maybe I=20
should ask at what point do you fire the injector in relation to the =
intake=20
valve rising off it's seat ?</DIV>
<DIV> </DIV>
<DIV>About the open/closed loop question I asked.......</DIV>
<DIV>We plan on running some in the Top Sportsman class which is merely =
a=20
bracket race once you qualify. Maximum HP isn't a necessity in this =
class.=20
Consistency is an absolute must so I was wondering if using a =
closed loop=20
(even if the engine is rich) would provide some advantage over =
carbureted=20
engines due to changing atmospheric conditions.</DIV>
<DIV>Also, we'll be able to electronically shift the transmission in =
this class=20
so the only variables other than the engine will be track & =
atmospheric=20
conditions. I just don't have a clue as to how fast the ecm reads the =
O=B2 sensor=20
& adjusts the fuel .</DIV>
<DIV>Any thoughts on this ?</DIV>
<DIV> </DIV>
<DIV>I'm in the process of making a decision about the cam position =
sensor. IMO=20
it would be better to have a large ring with 2 magnets (exactly 180 =
apart) on=20
the crankshaft rather than a small ring with 1 magnet on the camshaft. I =
have no=20
idea how accurate the ecm or magnetic pick-ups are. The crank trigger =
for the=20
ignition is about 8-9 inches & I'm guessing that the cam position =
sensor is=20
every bit as critical as the timing ?</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>I can provide pics of the intake set-up & hood scoop =
we have=20
if anyone is interested.</DIV>
<DIV> </DIV>
<DIV>Thanks to everyone for their input !!!!!!</DIV>
<DIV> </DIV></FONT></DIV></FONT></DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 2px solid; 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:rroberts2 at charter.net" =
title=3Drroberts2 at charter.net>mazak</A>=20
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
href=3D"mailto:diy_efi at diy-efi.org"=20
title=3Ddiy_efi at diy-efi.org>diy_efi at diy-efi.org</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Friday, August 02, 2002 =
1:04=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Sequential fire =
setup</DIV>
<DIV><BR></DIV>
<DIV><FONT face=3DArial size=3D2>
<DIV><FONT face=3DArial size=3D2>
<DIV>Hello</DIV>
<DIV><FONT face=3DArial size=3D2>After much thought my best friend =
& I have=20
decided to put sequential fire EFI on our drag car.</FONT><FONT =
face=3DArial=20
size=3D2> </FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I found this---> <A=20
=
href=3D"http://yarchive.net/car/fuel_injection.html">http://yarchive.net/=
car/fuel_injection.html</A></FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Very nice information---I learned =
more from this=20
than anything else I've read.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>We've already built a 91 Corvette =
drag car with a=20
L98 TPI (batch fire) & had a little success. The owner didn't want =
to dyno=20
the engine so everything has been a hit-or-miss considering our =
limited=20
knowledge of EFI. We're fully aware of the basic theory & =
operation but=20
since I read the post about sequential fire I've begun to wonder if =
there's=20
any advantage over batch or bank fire. </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>Here's what we're =
planning......</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>The car will weigh 2250-2350lbs & =
we're=20
hoping for 1200hp @8500rpm from our 565 BBC. </FONT></DIV>
<DIV><FONT face=3DArial size=3D2>The throttle bodies (4) each have 2 =
two inch=20
holes located directly over the fabricated intake =
runners.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>The injectors we're starting out with =
are 88lb=20
& the ecm is a FAST sequential fire. (<A=20
=
href=3D"http://www.fuelairspark.com/">http://www.fuelairspark.com/</A>)</=
FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>I guess I'm asking any of your =
personal opinions=20
of this since you seem to have full knowledge of EFI =
systems.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>It seems everyone we've spoken with =
so far gives=20
us vague information-----for example: What injector angle ? How much =
fuel=20
pressure ? What is the optimum EGT ? Open or closed loop if the engine =
is only=20
run at WOT ?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>I've got some general ideas about the =
answers to=20
these questions but no rock-solid advice.</FONT></DIV>
<DIV>We would gladly compensate the right person that would work =
closely with=20
us to get maximum HP.</DIV>
<DIV><FONT face=3DArial size=3D2>Weeks could be spent on the dyno =
without some=20
sort of baseline information.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Also, any tips or links to other =
online=20
information & articles would be greatly =
appreciated.</FONT></DIV>
<DIV>Anyone interested in helping please contact me asap.</DIV>
<DIV> </DIV>
<DIV>Thanks in advance</DIV>
<DIV>Ray Roberts</DIV>
<DIV> </DIV>
<DIV> </DIV></FONT></DIV></FONT></DIV></BLOCKQUOTE></BODY></HTML>
------=_NextPart_000_002E_01C23CFA.90230560--
_______________________________________________
Diy_efi mailing list
Diy_efi at diy-efi.org
http://www.diy-efi.org/mailman/listinfo/diy_efi
More information about the Diy_efi
mailing list