KENNE BELL in Cucamonga california &( MSD ELECTRONICS ) sells a
“boost-a-pump” - which basically raises the voltage to the tank mounted fuel
pump to 16 volts temporarily - while in “open loop” & under full throttle -
IE uses a vacuum or mechanical switch switch & some tricky wiring. Raising
the voltage raises the fuel pumps output & therfore the pressure at the
injector - with higher pressure & maximum commanded injector duty cycle -
that which characterises “open loop” - results in more fuel delivery. This
is a trick used oftem on souped up turbocars such as the grand national -
however, I saw a concept FORD EXPLORER at an autoshow & the FORD engineers
were using this gizmo to spice up the explorer in full throttle mode. They
wired the thing discretely into the crash-shutoff switch - using a connector
from another car to make it neat & neatly reverseable - IE just unplugs
…ALSO - KINSLER injector in MICHIGAN can sell you a high output version of
your factory fuel pump - they know alll the worlds fuel pumps & could supply
you with a higher pressure version of what you already have - in part
throttle mode - you vacuum / load sensing presure regulator would keep you
in factory specs - IE “closed loop”…
That is good info and sounds like solid performance gail would be possible. I
just don’t know how the Jag computer feed back would take to it but I suspect
the darn thing would just cut down on the number of on of cycles. That computer
system pretty much negates a lot of things that one does. I am planning on
removing the catalytic converters under the driver seat since they seem to have
reached their end at 188000. One has apparently broken ceramic because I can
hear it when I shake the tail pipe and it got in the new muffler the other may
by plugging I notice the volume of steam coming out the pipes when starting a
cold engine in damp weather is greater on pipe without the loose pieces rattling
about.
Cleaning and lubing he contacts with conductive lube (injectors) made a hell of
a difference for me. I had a dead spot on the power curve until 2000 rpm then
it would all of a sudden take off. After the cleaning there is no dead spot and
performance is awesome by comparison. Still how much can it hurt to try
boosting the pump output and seeing if it does give me a few more horses.
Thanks for the information
Jay 90 Majestic
R Mahoney wrote:> KENNE BELL in Cucamonga california &( MSD ELECTRONICS ) sells a
“boost-a-pump” - which basically raises the voltage to the tank mounted fuel
pump to 16 volts temporarily - while in “open loop” & under full throttle -
IE uses a vacuum or mechanical switch switch & some tricky wiring. Raising
the voltage raises the fuel pumps output & therfore the pressure at the
injector - with higher pressure & maximum commanded injector duty cycle -
that which characterises “open loop” - results in more fuel delivery. This
is a trick used oftem on souped up turbocars such as the grand national -
however, I saw a concept FORD EXPLORER at an autoshow & the FORD engineers
were using this gizmo to spice up the explorer in full throttle mode. They
wired the thing discretely into the crash-shutoff switch - using a connector
from another car to make it neat & neatly reverseable - IE just unplugs
…ALSO - KINSLER injector in MICHIGAN can sell you a high output version of
your factory fuel pump - they know alll the worlds fuel pumps & could supply
you with a higher pressure version of what you already have - in part
throttle mode - you vacuum / load sensing presure regulator would keep you
in factory specs - IE “closed loop”…
Biggy,
Does this new system do something with the fuel pressure
regulator on the fuel rail?
Its the fuel pressure regulator on the front of the fuel rail
that sets the pressure in the rail, not the pump.
The stock pump has NO problem supplying much more pressure
and flow than the engine can use.
The fuel pressure regulator is set to a range of 32 to 44
psi depending on the throttle/vacuum.
The pump can deliver a much higher pressure than this.
If you boost the pressure up, there must be a point where the injectors wont
be able to open against the pressure.
The oxy sensor will also correct the mixture at anything below
full throttle.
At full throttle, the ecu uses maps to set the mixture
in an open loop mode, with input from the maf sensor,
and the maps are set for 44 psi at the injectors.
The ecu is already set to enrich the mixture quite a bit,
any richer would not likely do anything except reduce
gas mileage.
If you were to move more air in and out of the engine, the maf
would sense this and increase the mixture to maintain the
optimal mixture for maximum power.
Another thing I noticed is that the injectors seem to
be very insensitive as to fuel pressure.
Pull off the vacuum line to the regulator and plug it,
and run the pressure at 44 psi all the time, and there
seems to be no change at all.
I don’t know if the special fuel pump device would work
on some cars, but seems like it would do nothing on
most cars I have seen except make the seller a bit richer…
Brett
1990 XJ6>
KENNE BELL in Cucamonga california &( MSD ELECTRONICS ) sells a
“boost-a-pump” - which basically raises the voltage to the
tank mounted fuel
pump to 16 volts temporarily - while in “open loop” & under
full throttle -
IE uses a vacuum or mechanical switch switch & some tricky
wiring. Raising
the voltage raises the fuel pumps output & therfore the
pressure at the
injector - with higher pressure & maximum commanded injector
duty cycle -
that which characterises “open loop” - results in more fuel
delivery. This
is a trick used oftem on souped up turbocars such as the
grand national -
however, I saw a concept FORD EXPLORER at an autoshow & the
FORD engineers
were using this gizmo to spice up the explorer in full
throttle mode. They
wired the thing discretely into the crash-shutoff switch -
using a connector
from another car to make it neat & neatly reverseable - IE
just unplugs
…ALSO - KINSLER injector in MICHIGAN can sell you a high
output version of
your factory fuel pump - they know alll the worlds fuel pumps
& could supply
you with a higher pressure version of what you already have - in part
throttle mode - you vacuum / load sensing presure regulator
would keep you
in factory specs - IE “closed loop”…
This thing is only for full throttle because of the fuel rail regulator -
however, Kinsler fuel injection can sell you either a trick aftermarket fuel
regulator to open the fuel delivery parameters OR an OEM bosch - IE off a
930 porsche etc… You are right, this does make things richer - where you
need it - full throttle.
I agreee with your assertion about the stock fuel pumps - Ive seen bad
regulators cause fule fail 23 codes - IE everything gets richened up &
eventually starts fouling plugs …
The only thing the computer controls at full throttle is spark timing - &
that is determined by detonation - IE the injectors go full duty cycle - so
therefore increasing the fuel pressure will increase the fuel delivery at
full throttle.
If I was to consider what you were considering - I would just get the 1994
XJR eaton/AJ6 setup & use the computer - you wouldnt be too far off … - you
also need to lower the static compression of your motor or you will blow a
headgasket & not realize the full potential of the boost - IE have WEISCO or
JE make you a set of custom pistons - probably $50 - 90 ea …
This thing is only for full throttle because of the fuel rail
regulator -
The fuel pressure regulator is still in line at full throttle.
The fuel pressure will go up from 32 psi to 44 psi with no
vacuum in the intake manifold.
however, Kinsler fuel injection can sell you either a trick
aftermarket fuel
regulator to open the fuel delivery parameters OR an OEM
bosch - IE off a
930 porsche etc… You are right, this does make things richer
where you
need it - full throttle.
So you would be boosting the pressure above 44 psi.
I wonder how they do that.
Putting pressure (instead of vacuum) on the vacuum
port will boost the pressure.
I agreee with your assertion about the stock fuel pumps - Ive seen bad
regulators cause fule fail 23 codes - IE everything gets richened up &
eventually starts fouling plugs …
Most times they leak into the vacuum port.
With age, the spring inside gets weak and the fuel
pressure drops, but it seems to have no effect on performance.
I bought a new regulator as a precaution, and it had
LOWER output pressure!
Still need more air to use the extra fuel so a blower would be to get the air in
to use the extra fuel
Jay
R Mahoney wrote:> This thing is only for full throttle because of the fuel rail regulator -
however, Kinsler fuel injection can sell you either a trick aftermarket fuel
regulator to open the fuel delivery parameters OR an OEM bosch - IE off a
930 porsche etc… You are right, this does make things richer - where you
need it - full throttle.
I agreee with your assertion about the stock fuel pumps - Ive seen bad
regulators cause fule fail 23 codes - IE everything gets richened up &
eventually starts fouling plugs …
Yea - That was what the freeflowing cats, and AJ6 engineering’s MAF, exhaust
& intake & airbox were all about - in the original post …Thats why we do
those things right ?
Many regulators never get to their upper limit due to weak fuel delivery
pumps - FOrd has a service bulletin about this on the late model Explorers
as a cure for lack of power - however, I believe if you raise the pressure
of the fuel delivery over specs - it will also raise the upper limit
pressure - because this is a Bosch fuel regulator - Kinsler ca supply a
another Bosch vacuum actuated regulator ( they know all the specs &
numbers ) - there are also several after market suppliers of these things …
KENNE BELL sells a tuneable machined unit - others are standart Bosch units
that have been either crushed to change there clearances OR that have had
half there body cut off & a machined tuneable chamber added thereto…Im
going to look into replacing my regulator as well - will let you know what I
find out …
It will be interesting to hear the results. Frankly, I am happy with the
performance I have now but one always has a yen to get a little more zip on
occasion. Don’t know that I modify my Majestic and I’ll probably buy one of the
new AWD Fordaurs this year for the wife.
I spent the weekend back east and visited my local dealer and like Brett, they
studiously ignored me after I asked if the parts department was open so I could
get some mineral oil. When my local mech replaced all my PS hoses he didn’t
order enough fluid. I was down a pint but drove to the airport 90 miles away to
catch flight and didn’t want to drive back without the level full. The good
news is all the leaking is fixed ( had about two pints on the garage floor over
the winter). The bad news is they new jurid just changed the point of
vibration. I am just going to take it to the Jag dealer and leave it for a
week so they get the drive shaft lined up and balanced. I’ve tired everything
else.
BTW They had as many XJ8 (is that what they call the X300?) as the new X type
(is the one with the Taurus like body the X version?). When I asked them what
models sold most they said the XJ8 was the better seller which is opposite from
what I had been hearing but then that was in RI. I also checked a road and
track on the new 400 HP Jag (still looks like a very ugly Taurus to me but
that’s my taste and does not imply that they are not good cars or intended to
anyone that spent money on one. That is there problem not mine.
The one thing that impressed me though was that the brand new XJ series still
looks an awful lot like my 90 Majestic (except for the round headlights which I
am not sure I like better than the Euro Block I have. I do like the smoother
tail and lights compared to mine though.
I’ll be happy when they make a Jag that doesn’t depreciate 70% in a couple of
years. But that’s what makes Jag a good buy. They still depreciate (or seem to
) faster than other Makes and you get a lot of car for the money with 60,000
miles on it which is nothing for these cars.
Good luck with your fuel boost experiment. I still think the oxysenor will
negate the gain unless you can get more air in the mixture but I will await your
test results with curiosity.
Jay 90 Majestic XJ6 VDP 188000
R Mahoney wrote:> Many regulators never get to their upper limit due to weak fuel delivery
pumps - FOrd has a service bulletin about this on the late model Explorers
as a cure for lack of power - however, I believe if you raise the pressure
of the fuel delivery over specs - it will also raise the upper limit
pressure - because this is a Bosch fuel regulator - Kinsler ca supply a
another Bosch vacuum actuated regulator ( they know all the specs &
numbers ) - there are also several after market suppliers of these things …
KENNE BELL sells a tuneable machined unit - others are standart Bosch units
that have been either crushed to change there clearances OR that have had
half there body cut off & a machined tuneable chamber added thereto…Im
going to look into replacing my regulator as well - will let you know what I
find out …