Might work out west but at maxton the condition of the track could very
possibly trip the switch.
Jim from Salem VA
-----Original Message-----
From: Joe Amo <jkamo@rapidnet.com>
To: Jonathan Amo <webmaster@amoproductions.com>
Cc: dahlgren <dahlgren@uconect.net>; land-speed@autox.team.net
<land-speed@autox.team.net>
Date: Tuesday, February 08, 2000 2:39 PM
Subject: Re: Cut off
>Dave, Jon and others, how about having the inertia switch isolated from
the circuit until
>it is armed after push off and "car is under its own power moving on down
course", I know a
>little more sophistication with the circuit, but have the driver arm the
circuit after the
>push off. Joe :) :)
>
>Jonathan Amo wrote:
>
>> Dave,
>>
>> You may be correct on the G factor rating, but isnt this what all the
chating is about,
>> if in fact of a wreck everybody wants a postive way to kill power to the
fuel pumps.
>> These fuel injection inertia switches can be mounted anywhere on the
vehicle, can be a
>> safe way to kill power to fuel pumps. And Like you say these are
triggered by a small
>> amount of G rating. And the driver in case of a wreck can point his
attention more to
>> bracing for impact or keeping his hands where he needs then instead of
trying to pull a
>> cutoff switch, lets the inertia switches do the work. Being in several
wrecks myself, my
>> mind isnt there going thru a checklist, im more curious on whats
happening, but those
>> that have been in a wreck, it goes by to damn fast to react sometimes
anyway. So in my
>> mind those inertia switches are a postive unit on any car. Just my
thoughts though, and
>> who am i anyway to question???
>>
>> Jonathan Amo
>>
>> dahlgren wrote:
>>
>> > You hit the reason why in your question.. "Sensitive little switches.."
>> > These respond to some fairly low G ratings..If i bump a car in the
>> > parking lot youare liable to set some of them off. So if when pushing
>> > someone off I bummp you a bit it may trip. And to my knowledge these
are
>> > not adjustable to suit racing needs. if my memory is correct I had
heard
>> > that a 5 or 10 mph hit is like 5 g's...The info i remember is from the
>> > old State Police crash simulator stuff of years gone by that was used
to
>> > remind people why they need to wear a seat belt.
>> > Dave Dahlgren
>> >
>> > Jonathan Amo wrote:
>> > >
>> > > Just out a curiosity why cant or dont people use the fuel inertia
cutoff switch for
>> > > the fuel pumps as all fuel injection cars have, in event of a wreck
these sensitive
>> > > little switches will automatically trip and cutoff power to fuel
pumps?
>> > >
>> > > Jonathan Amo
>> > >
>> > > Joe Amo wrote:
>> > >
>> > > > Dave, thank you very much for the tech info. It is very much
appreciated to
>> > > > hear such details, I am sure at times many refrain from expounding
about a
>> > > > particular matter, but many of us truly soak up the discussions
from the variety
>> > > > of sources on this list
>> > > > Thanks again, we are all the wiser (and safer) for it
Joe :)
>> > > > :) :)
>> > > >
>> > > > dahlgren wrote:
>> > > >
>> > > > > With an EFI System if it is installed correctly and the
controller is
>> > > > > worth anything at all should control the fuel pump. The normal
mode of
>> > > > > operation is as follows..
>> > > > >
>> > > > > switch on:
>> > > > > power up injector relay
>> > > > > power pump relay for 8 to 10 seconds to prime the fuel lines
>> > > > > shut off pump relay
>> > > > >
>> > > > > start position:
>> > > > > crank engine
>> > > > > if RPM is greater than 100 power up pump relay
>> > > > > engine starts
>> > > > >
>> > > > > run position:
>> > > > > keep injector relay powered up
>> > > > > check for RPM if less than 100 shut off pump relay
>> > > > > else power pump relay
>> > > > >
>> > > > > switch off:
>> > > > > shut off injector relay
>> > > > > when RPM drops below 100 shut off pump relay
>> > > > >
>> > > > > Do this over and over until you are tired of racing today, ran
out of
>> > > > > fuel, or blew the engine up....
>> > > > > A very quick check to see if this is installed correctly is to
turn the
>> > > > > switch to the on position..If the fuel pump runs for the 5 or 10
seconds
>> > > > > and then stops it is installed correctly..If your EFI does not do
this
>> > > > > there is one of a few problems.
>> > > > > #1 you installed or wired it incorrectly bypassing all the safety
>> > > > > methods built in to it.
>> > > > > #2 You intentionally thought you knew more than the engineers
that
>> > > > > designed the system and put in a manual switch.
>> > > > > #3 the system is so unsophisticated that it ought to be pulled
from the
>> > > > > market as it is a safety hazard..
>> > > > > This method works for every production car that i am aware of
that has
>> > > > > not been tampered with. The reason they(the auto companies) do it
this
>> > > > > way is to avoid the exact problem we are discussing. Fuel pump
running
>> > > > > in a crash or with the engine off. They do also use an inertia
switch to
>> > > > > shut off everything in the event of a crash but this is NOT
suitable for
>> > > > > a racing car..
>> > > > > The simplest way for the tech guys to check for a correct
installation
>> > > > > is to have the driver have only one switch to make the car run.
Have the
>> > > > > driver power it up and listen for the electric pump. It should
run for
>> > > > > the 5 to 10 seconds then stop. If it does not do this send them
to the
>> > > > > end of the line and have them fix it correctly. The installation
will be
>> > > > > safe when it passes this test..
>> > > > >
>> > > > > Dave Dahlgren
>> > > > > Engine Management Systems..
>> > > > >
>> > > > > BTW I am not reading from a user's manual on this.. I have
installed
>> > > > > tuned and designed EFI for the last 15 years...and write computer
code
>> > > > > that is inside EFI units that are for sale today....
>> > > > >
>> > > > > John Beckett wrote:
>> > > > > >
>> > > > > > Chris
>> > > > > >
>> > > > > > With EFI you really need a separate fuel pump shut off
switch. The Cut
>> > > > > > Off Switch we have been discussing on the list, in my opinion,
should
>> > > > > > disconnect everything electrical on the vehicle. But its not a
replacement
>> > > > > > for an individual fuel pump switch.
>> > > > > > The worst thing you can do is put in some sort of barrel
valve to stop
>> > > > > > fuel flow only. The problems created...increased line pressure
and current
>> > > > > > draw...will make things much worse.
>> > > > > >
>> > > > > > John Beckett, LSR #79
>> > > > > >
>> > > > > > ----- Original Message -----
>> > > > > > From: "Chris R Harris" <yesford@clear.net.nz>
>> > > > > > To: "land-speed" <land-speed@autox.team.net>
>> > > > > > Sent: Tuesday, February 08, 2000 1:17 AM
>> > > > > > Subject: Re: Cut off
>> > > > > >
>> > > > > > > List and especially Dan Warner,
>> > > > > > > I already have
a battery
>> > > > > > > isolating switch on the dash of my roadster in easy reach of
the driver
>> > > > > > and
>> > > > > > > will install a second in series in a location like the back
of the car
>> > > > > > like
>> > > > > > > the consensus suggest. My additional question is, with EFI,
will the dash
>> > > > > > > mounted battery isolater switch fill the requirement for a
fuel shut-off.
>> > > > > > > The dash switch will shut-off all current to the electric
pump, EFI
>> > > > > > > electronic control unit and ignition, or do I still require a
positive
>> > > > > > > mechanical barrel valve style fuel shut-off.
>> > > > > > > Chris Harris C/GR #397 New Zealand.
>
>
>
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