Bruno

Hitman wrote:
"I hope I can lay some of this AF Meter ranting to rest. I have
used
> extensively most types and brands of meters out there on the
market, as well as
> countless hours in the old days (8 years ago) of looking at Haltech
mV readings
> on the laptop screen. I have used the Autronic system which I am
still using
> today, the Motec unit, M&W NTK UEGO system..... UEGO sensors have
5-wires
> BTW..... , Autometer cheapie O2 Sensor gauges , the Haltech
Haltuner , a few
> home-made systems , and probably more than these that I have
forgotten about.
> This I would say gives me enough experience to know what works and
what doesn't.
>
> The true Bosche wide-band sensor equipped systems are more than
adequate to use
> to tune your car under all operating conditions. Any system
running these
> sensors will retail at around US$1000.00 or higher due to the
careful
> calibration , temperature correction algorithms, and all the rest
of the
> electronics to read it accurately. The Bosche wide-band sensor is
quite thick
> in the body but still fits the standard 18x1.5mm thread, 4-wires
going through a
> heat-proof jacket, and usually terminated in two plugs that look
like injector
> clips ... one male one female.
> The normal NTK 4-wire sensor that most cheap AF Meter kits will use
has a slim
> body and same thread size. It is only of any accuracy when reading
14.0 - 15.5
> for A/F ratio. Even then they are not temperature corrected.
Once you get
> below 13.3:1 they become quite erratic in their readings and should
not be
> relied on. If you are stuck in the middle of nowhere and one of
these meters is
> your only option , tune wide open throttle so that it never reads
less than
> full-rich on the scale. You should normally be aiming for mid to
low 12:1 for
> less than 10psi , and high 11:1 for above that.
> If you are running a single wire sensor I am afraid to say they are
quite
> useless and you should save up some cash to at the very least run a
4-wire
> sensor.
>
> So there you go Eric , the basics of AF Meters and I think it is
OK for you to
> use a normal 02 sensor for tuning when nothing else is available.
>
> One other hint for tuning with these devices. Stoic is only wanted
on these
> motors if economy and emmisions are a concern. If all you want is
the best power
> and response then you should never come close to running even as
lean as 13.8:1
> Best power on the 13B is made at 12.7:1 and you will all find this
most easily
> when tuning idle mixtures. The engine will run at its highest revs
when set to
> this mixture exactly indicating a higher torque output. Same
happens all
> through the load and rev range except under boost where it will
need richer to
> help prevent detonation.
>
> I hope my little rave here can help a few of you out and maybe end
the AF Meter
> dabate.
> --
> Matt
> The HITman - Haltech Injection Tuning
> http://www.hitman.hm:"

Hi to everyone.

I think that the best way to get advantage of this forum is to start
reading all your posts from the beginning maybe all the answers are
already written so why ask again.
So I decided to start reading all the post before installing my
haltech system and I came up with this post from may 2000 written by
Hitman.

You mention in this post that I should be aiming at 12.7:1 fuel air
ratio, but dont say anything about EGT tempetures.

As I have learn from reading there is a big diference between 12.7:1
at 500C and 900C, At 900 degrees 12.7:1 is about 0.81 volts and at
500C is 0.95 volts.
So I think that there is a relationship here that needs to be mention
here.
Is there a way that haltech can feedback from a EGT It will help a
lot I think. Suppost that you are running 12:1 and you think that you
have the perfect air/fuel mixture. Suppost that one day you look at
your data log and you see that wonderfull 12:1 ratio wow. But? was it
actually 12:1 at lets say 500 degres C. (0.97 volts) or was it 12:1
at 900 degres c. (0.84 volts). Suppost you were running 13:1 instead,
big problem eh.
Now 3 questions
1 what about EGT reading in Haltech?
2 What egt tempetures are you talking about here when you say 12.7:1?
3 What safe ratio for 20 pounds of boost looking for max hp? Any
Ideas?

Thanks to everyone
Bruno

HWO

i'll spit in my 2 cents worth here:

1)are EGT's really that important? see 2.

2)I am PRETTY SURE you'll find that wideband sensors have temperature correction in them, so 12.7:1 is 12.7:1 weather its at -10 or +1000

3) no leaner than 11:1 at 20psi, play it safe and stick to 10.5:1 above 14psi