4.2 tbi
02-05-2006, 02:15 PM
#11
Guest
Posts: n/a
Re: 4.2 tbi
Mike Romain wrote:
> Too bad you have to pay big in gas mileage for that 'reliability'....
Mike, fuel injection is better for mileage... That Carter isn't better
than FI in any way shape or form, let alone delivering fuel efficiently.
Most TBI writeups on the web claim 1 to 4 MPG increase after TBI, and
the MPI writups claim even more. One of them even claims a 6 MPG
increase. Although I can't find it right now. Sure these are probably
replacing badly running Carters, but then most of them never ran very
well to begin with.
Assuming he's replacing a emissions era Carter his power will increase
as well, JUST getting rid of that POS carter is worth a couple HP, more
if it's out of tune and needing a rebuild (and they all are) when you
put a higher CFM part in it's place (those GM TBI's are generally 300
CFM versus the Carter's 260), and then disable all that air flow
impeding, and air density robbing heater crap and emissions equipment,
things start getting interesting.
Stock that system comes with a door in the housing that mildly restricts
airflow; an electric heater; an exhaust riser heater that warms the
intake air; while these are supposed to only work at start up you also
have the EGR pumping warm exhaust into the carb; pulse air tubes,
pumping warm air into the housing (possibly constantly depending on what
shape his are in); AND as if that's not enough, the coolant is sent
through the intake manifold, AND the exhaust manifold is radiating heat
onto it to the point where the intake can burn you.
Losing the Carter and all that heater garbage Almost all of which is
there ONLY to aid fuel atomization in that horrible carb, is probably
worth 10 or 15 peak HP, over a _perfectly_ running BBD.
--
Simon
"I may be wrong, but I'm not uncertain." -- Robert A. Heinlein
> Too bad you have to pay big in gas mileage for that 'reliability'....
Mike, fuel injection is better for mileage... That Carter isn't better
than FI in any way shape or form, let alone delivering fuel efficiently.
Most TBI writeups on the web claim 1 to 4 MPG increase after TBI, and
the MPI writups claim even more. One of them even claims a 6 MPG
increase. Although I can't find it right now. Sure these are probably
replacing badly running Carters, but then most of them never ran very
well to begin with.
Assuming he's replacing a emissions era Carter his power will increase
as well, JUST getting rid of that POS carter is worth a couple HP, more
if it's out of tune and needing a rebuild (and they all are) when you
put a higher CFM part in it's place (those GM TBI's are generally 300
CFM versus the Carter's 260), and then disable all that air flow
impeding, and air density robbing heater crap and emissions equipment,
things start getting interesting.
Stock that system comes with a door in the housing that mildly restricts
airflow; an electric heater; an exhaust riser heater that warms the
intake air; while these are supposed to only work at start up you also
have the EGR pumping warm exhaust into the carb; pulse air tubes,
pumping warm air into the housing (possibly constantly depending on what
shape his are in); AND as if that's not enough, the coolant is sent
through the intake manifold, AND the exhaust manifold is radiating heat
onto it to the point where the intake can burn you.
Losing the Carter and all that heater garbage Almost all of which is
there ONLY to aid fuel atomization in that horrible carb, is probably
worth 10 or 15 peak HP, over a _perfectly_ running BBD.
--
Simon
"I may be wrong, but I'm not uncertain." -- Robert A. Heinlein
02-05-2006, 02:15 PM
#12
Guest
Posts: n/a
Re: 4.2 tbi
Mike Romain wrote:
> Too bad you have to pay big in gas mileage for that 'reliability'....
Mike, fuel injection is better for mileage... That Carter isn't better
than FI in any way shape or form, let alone delivering fuel efficiently.
Most TBI writeups on the web claim 1 to 4 MPG increase after TBI, and
the MPI writups claim even more. One of them even claims a 6 MPG
increase. Although I can't find it right now. Sure these are probably
replacing badly running Carters, but then most of them never ran very
well to begin with.
Assuming he's replacing a emissions era Carter his power will increase
as well, JUST getting rid of that POS carter is worth a couple HP, more
if it's out of tune and needing a rebuild (and they all are) when you
put a higher CFM part in it's place (those GM TBI's are generally 300
CFM versus the Carter's 260), and then disable all that air flow
impeding, and air density robbing heater crap and emissions equipment,
things start getting interesting.
Stock that system comes with a door in the housing that mildly restricts
airflow; an electric heater; an exhaust riser heater that warms the
intake air; while these are supposed to only work at start up you also
have the EGR pumping warm exhaust into the carb; pulse air tubes,
pumping warm air into the housing (possibly constantly depending on what
shape his are in); AND as if that's not enough, the coolant is sent
through the intake manifold, AND the exhaust manifold is radiating heat
onto it to the point where the intake can burn you.
Losing the Carter and all that heater garbage Almost all of which is
there ONLY to aid fuel atomization in that horrible carb, is probably
worth 10 or 15 peak HP, over a _perfectly_ running BBD.
--
Simon
"I may be wrong, but I'm not uncertain." -- Robert A. Heinlein
> Too bad you have to pay big in gas mileage for that 'reliability'....
Mike, fuel injection is better for mileage... That Carter isn't better
than FI in any way shape or form, let alone delivering fuel efficiently.
Most TBI writeups on the web claim 1 to 4 MPG increase after TBI, and
the MPI writups claim even more. One of them even claims a 6 MPG
increase. Although I can't find it right now. Sure these are probably
replacing badly running Carters, but then most of them never ran very
well to begin with.
Assuming he's replacing a emissions era Carter his power will increase
as well, JUST getting rid of that POS carter is worth a couple HP, more
if it's out of tune and needing a rebuild (and they all are) when you
put a higher CFM part in it's place (those GM TBI's are generally 300
CFM versus the Carter's 260), and then disable all that air flow
impeding, and air density robbing heater crap and emissions equipment,
things start getting interesting.
Stock that system comes with a door in the housing that mildly restricts
airflow; an electric heater; an exhaust riser heater that warms the
intake air; while these are supposed to only work at start up you also
have the EGR pumping warm exhaust into the carb; pulse air tubes,
pumping warm air into the housing (possibly constantly depending on what
shape his are in); AND as if that's not enough, the coolant is sent
through the intake manifold, AND the exhaust manifold is radiating heat
onto it to the point where the intake can burn you.
Losing the Carter and all that heater garbage Almost all of which is
there ONLY to aid fuel atomization in that horrible carb, is probably
worth 10 or 15 peak HP, over a _perfectly_ running BBD.
--
Simon
"I may be wrong, but I'm not uncertain." -- Robert A. Heinlein
02-05-2006, 02:15 PM
#13
Guest
Posts: n/a
Re: 4.2 tbi
Mike Romain wrote:
> Too bad you have to pay big in gas mileage for that 'reliability'....
Mike, fuel injection is better for mileage... That Carter isn't better
than FI in any way shape or form, let alone delivering fuel efficiently.
Most TBI writeups on the web claim 1 to 4 MPG increase after TBI, and
the MPI writups claim even more. One of them even claims a 6 MPG
increase. Although I can't find it right now. Sure these are probably
replacing badly running Carters, but then most of them never ran very
well to begin with.
Assuming he's replacing a emissions era Carter his power will increase
as well, JUST getting rid of that POS carter is worth a couple HP, more
if it's out of tune and needing a rebuild (and they all are) when you
put a higher CFM part in it's place (those GM TBI's are generally 300
CFM versus the Carter's 260), and then disable all that air flow
impeding, and air density robbing heater crap and emissions equipment,
things start getting interesting.
Stock that system comes with a door in the housing that mildly restricts
airflow; an electric heater; an exhaust riser heater that warms the
intake air; while these are supposed to only work at start up you also
have the EGR pumping warm exhaust into the carb; pulse air tubes,
pumping warm air into the housing (possibly constantly depending on what
shape his are in); AND as if that's not enough, the coolant is sent
through the intake manifold, AND the exhaust manifold is radiating heat
onto it to the point where the intake can burn you.
Losing the Carter and all that heater garbage Almost all of which is
there ONLY to aid fuel atomization in that horrible carb, is probably
worth 10 or 15 peak HP, over a _perfectly_ running BBD.
--
Simon
"I may be wrong, but I'm not uncertain." -- Robert A. Heinlein
> Too bad you have to pay big in gas mileage for that 'reliability'....
Mike, fuel injection is better for mileage... That Carter isn't better
than FI in any way shape or form, let alone delivering fuel efficiently.
Most TBI writeups on the web claim 1 to 4 MPG increase after TBI, and
the MPI writups claim even more. One of them even claims a 6 MPG
increase. Although I can't find it right now. Sure these are probably
replacing badly running Carters, but then most of them never ran very
well to begin with.
Assuming he's replacing a emissions era Carter his power will increase
as well, JUST getting rid of that POS carter is worth a couple HP, more
if it's out of tune and needing a rebuild (and they all are) when you
put a higher CFM part in it's place (those GM TBI's are generally 300
CFM versus the Carter's 260), and then disable all that air flow
impeding, and air density robbing heater crap and emissions equipment,
things start getting interesting.
Stock that system comes with a door in the housing that mildly restricts
airflow; an electric heater; an exhaust riser heater that warms the
intake air; while these are supposed to only work at start up you also
have the EGR pumping warm exhaust into the carb; pulse air tubes,
pumping warm air into the housing (possibly constantly depending on what
shape his are in); AND as if that's not enough, the coolant is sent
through the intake manifold, AND the exhaust manifold is radiating heat
onto it to the point where the intake can burn you.
Losing the Carter and all that heater garbage Almost all of which is
there ONLY to aid fuel atomization in that horrible carb, is probably
worth 10 or 15 peak HP, over a _perfectly_ running BBD.
--
Simon
"I may be wrong, but I'm not uncertain." -- Robert A. Heinlein
02-05-2006, 03:26 PM
#14
Guest
Posts: n/a
Re: 4.2 tbi
Simon Juncal wrote:
>
> Mike Romain wrote:
> > Too bad you have to pay big in gas mileage for that 'reliability'....
>
> Mike, fuel injection is better for mileage... That Carter isn't better
> than FI in any way shape or form, let alone delivering fuel efficiently.
>
> Most TBI writeups on the web claim 1 to 4 MPG increase after TBI, and
> the MPI writups claim even more. One of them even claims a 6 MPG
> increase. Although I can't find it right now. Sure these are probably
> replacing badly running Carters, but then most of them never ran very
> well to begin with.
>
> Assuming he's replacing a emissions era Carter his power will increase
> as well, JUST getting rid of that POS carter is worth a couple HP, more
> if it's out of tune and needing a rebuild (and they all are) when you
> put a higher CFM part in it's place (those GM TBI's are generally 300
> CFM versus the Carter's 260), and then disable all that air flow
> impeding, and air density robbing heater crap and emissions equipment,
> things start getting interesting.
>
> Stock that system comes with a door in the housing that mildly restricts
> airflow; an electric heater; an exhaust riser heater that warms the
> intake air; while these are supposed to only work at start up you also
> have the EGR pumping warm exhaust into the carb; pulse air tubes,
> pumping warm air into the housing (possibly constantly depending on what
> shape his are in); AND as if that's not enough, the coolant is sent
> through the intake manifold, AND the exhaust manifold is radiating heat
> onto it to the point where the intake can burn you.
>
> Losing the Carter and all that heater garbage Almost all of which is
> there ONLY to aid fuel atomization in that horrible carb, is probably
> worth 10 or 15 peak HP, over a _perfectly_ running BBD.
>
> --
> Simon
I dumped the Ford emissions computer and regularly put the $20.00
rebuild kit into my BBD and that sucker just rocks! I have done the
same for several others and got the same results. Folks forget the Carb
is supposed to get a kit with every plug change...
We all pass emissions easily or with a slight lean tweak needed because
the sniffer likes the idle to lean rumble slightly and I get a sweet 23
mpg running about 65-70 mph.
Killing the computer frees up about 25% power or as Jo put it, over 10
mph more per gear way faster. I also believe the gas mileage boost also
come from that and running 91 octane 'gasoline', not mix. If I run mix,
I drop down to 18 mpg.
Mine will light up my 33's from a stop, second hits 53 mph at 4400 rpm,
3 hauls fast to 75 mph, 4th buries the speedo easy and I have 'no' urge
to find out how fast 5th goes....
I think the mpg boost the FI systems show is only because all that Ford
emissions crap gets dumped, same as doing the 'Nutter' bypass.
I really like my setup.
That all said, I do like our Cherokee's FI system with nothing to have
mess with too often....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
>
> Mike Romain wrote:
> > Too bad you have to pay big in gas mileage for that 'reliability'....
>
> Mike, fuel injection is better for mileage... That Carter isn't better
> than FI in any way shape or form, let alone delivering fuel efficiently.
>
> Most TBI writeups on the web claim 1 to 4 MPG increase after TBI, and
> the MPI writups claim even more. One of them even claims a 6 MPG
> increase. Although I can't find it right now. Sure these are probably
> replacing badly running Carters, but then most of them never ran very
> well to begin with.
>
> Assuming he's replacing a emissions era Carter his power will increase
> as well, JUST getting rid of that POS carter is worth a couple HP, more
> if it's out of tune and needing a rebuild (and they all are) when you
> put a higher CFM part in it's place (those GM TBI's are generally 300
> CFM versus the Carter's 260), and then disable all that air flow
> impeding, and air density robbing heater crap and emissions equipment,
> things start getting interesting.
>
> Stock that system comes with a door in the housing that mildly restricts
> airflow; an electric heater; an exhaust riser heater that warms the
> intake air; while these are supposed to only work at start up you also
> have the EGR pumping warm exhaust into the carb; pulse air tubes,
> pumping warm air into the housing (possibly constantly depending on what
> shape his are in); AND as if that's not enough, the coolant is sent
> through the intake manifold, AND the exhaust manifold is radiating heat
> onto it to the point where the intake can burn you.
>
> Losing the Carter and all that heater garbage Almost all of which is
> there ONLY to aid fuel atomization in that horrible carb, is probably
> worth 10 or 15 peak HP, over a _perfectly_ running BBD.
>
> --
> Simon
I dumped the Ford emissions computer and regularly put the $20.00
rebuild kit into my BBD and that sucker just rocks! I have done the
same for several others and got the same results. Folks forget the Carb
is supposed to get a kit with every plug change...
We all pass emissions easily or with a slight lean tweak needed because
the sniffer likes the idle to lean rumble slightly and I get a sweet 23
mpg running about 65-70 mph.
Killing the computer frees up about 25% power or as Jo put it, over 10
mph more per gear way faster. I also believe the gas mileage boost also
come from that and running 91 octane 'gasoline', not mix. If I run mix,
I drop down to 18 mpg.
Mine will light up my 33's from a stop, second hits 53 mph at 4400 rpm,
3 hauls fast to 75 mph, 4th buries the speedo easy and I have 'no' urge
to find out how fast 5th goes....
I think the mpg boost the FI systems show is only because all that Ford
emissions crap gets dumped, same as doing the 'Nutter' bypass.
I really like my setup.
That all said, I do like our Cherokee's FI system with nothing to have
mess with too often....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
02-05-2006, 03:26 PM
#15
Guest
Posts: n/a
Re: 4.2 tbi
Simon Juncal wrote:
>
> Mike Romain wrote:
> > Too bad you have to pay big in gas mileage for that 'reliability'....
>
> Mike, fuel injection is better for mileage... That Carter isn't better
> than FI in any way shape or form, let alone delivering fuel efficiently.
>
> Most TBI writeups on the web claim 1 to 4 MPG increase after TBI, and
> the MPI writups claim even more. One of them even claims a 6 MPG
> increase. Although I can't find it right now. Sure these are probably
> replacing badly running Carters, but then most of them never ran very
> well to begin with.
>
> Assuming he's replacing a emissions era Carter his power will increase
> as well, JUST getting rid of that POS carter is worth a couple HP, more
> if it's out of tune and needing a rebuild (and they all are) when you
> put a higher CFM part in it's place (those GM TBI's are generally 300
> CFM versus the Carter's 260), and then disable all that air flow
> impeding, and air density robbing heater crap and emissions equipment,
> things start getting interesting.
>
> Stock that system comes with a door in the housing that mildly restricts
> airflow; an electric heater; an exhaust riser heater that warms the
> intake air; while these are supposed to only work at start up you also
> have the EGR pumping warm exhaust into the carb; pulse air tubes,
> pumping warm air into the housing (possibly constantly depending on what
> shape his are in); AND as if that's not enough, the coolant is sent
> through the intake manifold, AND the exhaust manifold is radiating heat
> onto it to the point where the intake can burn you.
>
> Losing the Carter and all that heater garbage Almost all of which is
> there ONLY to aid fuel atomization in that horrible carb, is probably
> worth 10 or 15 peak HP, over a _perfectly_ running BBD.
>
> --
> Simon
I dumped the Ford emissions computer and regularly put the $20.00
rebuild kit into my BBD and that sucker just rocks! I have done the
same for several others and got the same results. Folks forget the Carb
is supposed to get a kit with every plug change...
We all pass emissions easily or with a slight lean tweak needed because
the sniffer likes the idle to lean rumble slightly and I get a sweet 23
mpg running about 65-70 mph.
Killing the computer frees up about 25% power or as Jo put it, over 10
mph more per gear way faster. I also believe the gas mileage boost also
come from that and running 91 octane 'gasoline', not mix. If I run mix,
I drop down to 18 mpg.
Mine will light up my 33's from a stop, second hits 53 mph at 4400 rpm,
3 hauls fast to 75 mph, 4th buries the speedo easy and I have 'no' urge
to find out how fast 5th goes....
I think the mpg boost the FI systems show is only because all that Ford
emissions crap gets dumped, same as doing the 'Nutter' bypass.
I really like my setup.
That all said, I do like our Cherokee's FI system with nothing to have
mess with too often....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
>
> Mike Romain wrote:
> > Too bad you have to pay big in gas mileage for that 'reliability'....
>
> Mike, fuel injection is better for mileage... That Carter isn't better
> than FI in any way shape or form, let alone delivering fuel efficiently.
>
> Most TBI writeups on the web claim 1 to 4 MPG increase after TBI, and
> the MPI writups claim even more. One of them even claims a 6 MPG
> increase. Although I can't find it right now. Sure these are probably
> replacing badly running Carters, but then most of them never ran very
> well to begin with.
>
> Assuming he's replacing a emissions era Carter his power will increase
> as well, JUST getting rid of that POS carter is worth a couple HP, more
> if it's out of tune and needing a rebuild (and they all are) when you
> put a higher CFM part in it's place (those GM TBI's are generally 300
> CFM versus the Carter's 260), and then disable all that air flow
> impeding, and air density robbing heater crap and emissions equipment,
> things start getting interesting.
>
> Stock that system comes with a door in the housing that mildly restricts
> airflow; an electric heater; an exhaust riser heater that warms the
> intake air; while these are supposed to only work at start up you also
> have the EGR pumping warm exhaust into the carb; pulse air tubes,
> pumping warm air into the housing (possibly constantly depending on what
> shape his are in); AND as if that's not enough, the coolant is sent
> through the intake manifold, AND the exhaust manifold is radiating heat
> onto it to the point where the intake can burn you.
>
> Losing the Carter and all that heater garbage Almost all of which is
> there ONLY to aid fuel atomization in that horrible carb, is probably
> worth 10 or 15 peak HP, over a _perfectly_ running BBD.
>
> --
> Simon
I dumped the Ford emissions computer and regularly put the $20.00
rebuild kit into my BBD and that sucker just rocks! I have done the
same for several others and got the same results. Folks forget the Carb
is supposed to get a kit with every plug change...
We all pass emissions easily or with a slight lean tweak needed because
the sniffer likes the idle to lean rumble slightly and I get a sweet 23
mpg running about 65-70 mph.
Killing the computer frees up about 25% power or as Jo put it, over 10
mph more per gear way faster. I also believe the gas mileage boost also
come from that and running 91 octane 'gasoline', not mix. If I run mix,
I drop down to 18 mpg.
Mine will light up my 33's from a stop, second hits 53 mph at 4400 rpm,
3 hauls fast to 75 mph, 4th buries the speedo easy and I have 'no' urge
to find out how fast 5th goes....
I think the mpg boost the FI systems show is only because all that Ford
emissions crap gets dumped, same as doing the 'Nutter' bypass.
I really like my setup.
That all said, I do like our Cherokee's FI system with nothing to have
mess with too often....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
02-05-2006, 03:26 PM
#16
Guest
Posts: n/a
Re: 4.2 tbi
Simon Juncal wrote:
>
> Mike Romain wrote:
> > Too bad you have to pay big in gas mileage for that 'reliability'....
>
> Mike, fuel injection is better for mileage... That Carter isn't better
> than FI in any way shape or form, let alone delivering fuel efficiently.
>
> Most TBI writeups on the web claim 1 to 4 MPG increase after TBI, and
> the MPI writups claim even more. One of them even claims a 6 MPG
> increase. Although I can't find it right now. Sure these are probably
> replacing badly running Carters, but then most of them never ran very
> well to begin with.
>
> Assuming he's replacing a emissions era Carter his power will increase
> as well, JUST getting rid of that POS carter is worth a couple HP, more
> if it's out of tune and needing a rebuild (and they all are) when you
> put a higher CFM part in it's place (those GM TBI's are generally 300
> CFM versus the Carter's 260), and then disable all that air flow
> impeding, and air density robbing heater crap and emissions equipment,
> things start getting interesting.
>
> Stock that system comes with a door in the housing that mildly restricts
> airflow; an electric heater; an exhaust riser heater that warms the
> intake air; while these are supposed to only work at start up you also
> have the EGR pumping warm exhaust into the carb; pulse air tubes,
> pumping warm air into the housing (possibly constantly depending on what
> shape his are in); AND as if that's not enough, the coolant is sent
> through the intake manifold, AND the exhaust manifold is radiating heat
> onto it to the point where the intake can burn you.
>
> Losing the Carter and all that heater garbage Almost all of which is
> there ONLY to aid fuel atomization in that horrible carb, is probably
> worth 10 or 15 peak HP, over a _perfectly_ running BBD.
>
> --
> Simon
I dumped the Ford emissions computer and regularly put the $20.00
rebuild kit into my BBD and that sucker just rocks! I have done the
same for several others and got the same results. Folks forget the Carb
is supposed to get a kit with every plug change...
We all pass emissions easily or with a slight lean tweak needed because
the sniffer likes the idle to lean rumble slightly and I get a sweet 23
mpg running about 65-70 mph.
Killing the computer frees up about 25% power or as Jo put it, over 10
mph more per gear way faster. I also believe the gas mileage boost also
come from that and running 91 octane 'gasoline', not mix. If I run mix,
I drop down to 18 mpg.
Mine will light up my 33's from a stop, second hits 53 mph at 4400 rpm,
3 hauls fast to 75 mph, 4th buries the speedo easy and I have 'no' urge
to find out how fast 5th goes....
I think the mpg boost the FI systems show is only because all that Ford
emissions crap gets dumped, same as doing the 'Nutter' bypass.
I really like my setup.
That all said, I do like our Cherokee's FI system with nothing to have
mess with too often....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)
>
> Mike Romain wrote:
> > Too bad you have to pay big in gas mileage for that 'reliability'....
>
> Mike, fuel injection is better for mileage... That Carter isn't better
> than FI in any way shape or form, let alone delivering fuel efficiently.
>
> Most TBI writeups on the web claim 1 to 4 MPG increase after TBI, and
> the MPI writups claim even more. One of them even claims a 6 MPG
> increase. Although I can't find it right now. Sure these are probably
> replacing badly running Carters, but then most of them never ran very
> well to begin with.
>
> Assuming he's replacing a emissions era Carter his power will increase
> as well, JUST getting rid of that POS carter is worth a couple HP, more
> if it's out of tune and needing a rebuild (and they all are) when you
> put a higher CFM part in it's place (those GM TBI's are generally 300
> CFM versus the Carter's 260), and then disable all that air flow
> impeding, and air density robbing heater crap and emissions equipment,
> things start getting interesting.
>
> Stock that system comes with a door in the housing that mildly restricts
> airflow; an electric heater; an exhaust riser heater that warms the
> intake air; while these are supposed to only work at start up you also
> have the EGR pumping warm exhaust into the carb; pulse air tubes,
> pumping warm air into the housing (possibly constantly depending on what
> shape his are in); AND as if that's not enough, the coolant is sent
> through the intake manifold, AND the exhaust manifold is radiating heat
> onto it to the point where the intake can burn you.
>
> Losing the Carter and all that heater garbage Almost all of which is
> there ONLY to aid fuel atomization in that horrible carb, is probably
> worth 10 or 15 peak HP, over a _perfectly_ running BBD.
>
> --
> Simon
I dumped the Ford emissions computer and regularly put the $20.00
rebuild kit into my BBD and that sucker just rocks! I have done the
same for several others and got the same results. Folks forget the Carb
is supposed to get a kit with every plug change...
We all pass emissions easily or with a slight lean tweak needed because
the sniffer likes the idle to lean rumble slightly and I get a sweet 23
mpg running about 65-70 mph.
Killing the computer frees up about 25% power or as Jo put it, over 10
mph more per gear way faster. I also believe the gas mileage boost also
come from that and running 91 octane 'gasoline', not mix. If I run mix,
I drop down to 18 mpg.
Mine will light up my 33's from a stop, second hits 53 mph at 4400 rpm,
3 hauls fast to 75 mph, 4th buries the speedo easy and I have 'no' urge
to find out how fast 5th goes....
I think the mpg boost the FI systems show is only because all that Ford
emissions crap gets dumped, same as doing the 'Nutter' bypass.
I really like my setup.
That all said, I do like our Cherokee's FI system with nothing to have
mess with too often....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
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Jacob
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07-06-2004 01:17 PM
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