Re: Stock CIS, running out of gas at 2 bar?

["Scott M." <scottmo@teleport.com>]

Turbo,

> 	 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.

Well according to the Bosch book, with the K-Lamda system,
the movement of the plate and the corresponding movement of
the plunger is indeed linear. But, I will look into this
some more and see as I am not convinced the movement is
linear either.

>I have ridden in Neds cars and 300-325 hp can be achieved
> quite easily.

Well, I guess one question that arises in my feeble mind,
is just how and where was this "quoted" 300-325 HP "figure"
derived? WAG? (wild ass guess) I have never heard of any
actual dyno runs, have you? I too have driven in Neds cars
on several occasions, but I'm afraid my butt has not been
calibrated in HP lately.

> 	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.

Well, I would love to believe you, but it would help if you
had some data, i.e. fuel flow (injector) testing at full
sensor movement?, Bosch fuel distributor specifications? I
would like to do the test myself soon, but if you have
already done this, it would save me from yanking out all my
injectors (again).

> 	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.

Well, I wasn't trying to imply that my test was accurate
other than telling me that the sensor plate is near the top
of its travel. Sorry if I implied otherwise.

> 	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.

Yes, this is a good idea, and you are right, as long as
their is still some movement left, and the fuel is still
being provided at the correct A/F ratio.

> 	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.

Yes, there are many ways to sense running out of fuel,
massive pinging might be another.
The O2 sensor voltage is not very accurate, I'm afraid, yes
it will give you some indication as to whether you are
grossly lean, but don't expect me to believe that it will
tell me whether I have 10.6 to 1 A/F ratio or whether I
actually have 12.6 to 1 A/F ratio. I have read way too many
SAE design articles on O2 sensors that indicate that thing
ain't gonna cut it. There are some new O2 sensors that will
give accurate A/F ratios but these are in limited use. Read
some articles on these sensors as well.

Oh, I have a very nice portable 4 gas exhaust analyzer that
I have used under sustained full throttle, (1.8 bar boost)
conditions in 4th gear at ~5500 RPM, and my analyzer
indicated the A/F ratio was about 12.8 to 1 which told me
everything was pretty much ok. I just am wondering how much
more it can provide if the boost was increased to 2.0 Bar?

> 	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.

Well, shoot away, I love a good technical discussion, but
just because there are a lot of people out there running
over 2.0 bar doesn't convince me they have a clue what the
A/F ratio being delivered to the engine or what is going
out their tailpipe.

Drive fast, and take chances
Cheers
Scott M.