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Re: Stock CIS, running out of gas at 2 bar?
Scott M. wrote:
> I was doing some testing yesterday on my 89 200TQ where I
> measured the voltage output from the CIS Air-flow plate
> potentiometer (used for fuel mileage calculation). This
> potentiometer (variable resistor) tells the dash computer
> how high the air-flow plate rises while you are driving.
> With the ign. key on and the air flow plate pushed up by
> hand to the top of its travel (max air flow) the voltage
> output was 4.465 V.
> I remember Ned quoting that the stock fuel injection was
> good to 300-325 HP, at this point, I think that figure may
> need to be reduced a bit.
> Scott M.
The travel of the air flow sensor plate is not linear just look at the
shape of the funel the plate rides in.all of the air goes around the
plate and the shape of the funel regulates the amount of lift and the
amount of fuel.I have ridden in Neds cars and 300-325 hp can be achieved
On fuel flow an engine needs .5Lb of fuel per horsepower per hour so
300hp requires 150Lb fuel or @ 6Lbs/gallon gas 25 gallons of fuel per
hour.And believe me this fuel system can deliver at least this much.
Checking the plate travel with the potieometer is a good idea but I
dont think it is as accurate as you would like it to be.
To be safe though check your work reconnect the volt meter and lift the
air flow sensor plate until the voltage is the same as it was during
your test and check the travel that is left it may not be much but as
long as some is left it doesnt matter.
There are many other ways of checking if the engine is running out of
fuel like; reading spark plugs,connecting a portable gas
analyzer,reading 02 sensor voltage,checking fuel pressure.
I am not trying to shoot down your testing.It is nice to see somebody
is thinking but remember there are many people on this list who are
running much more than 2.0 bar boost and are not running into fuel
delivery problems.GOOD LUCK!HAVE FUN!DRIVE SAFELY!!