I'm not arguing that there aren't other factors involved, but even by your
equation, the IAT is part of it. You change ANY value in the equation and
the end result changes too. And since that includes IAT, then, by posting
that formula, you supported what I said that tricking the PCM into thinking
the IAT is lower than it actually is, you are changing the PW and therefore
amount of fuel used. Or are you going to try and argue that the formula
doesn't work the way it's written??
brian cropp
-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Bernd D.
Ratsch
Sent: Friday, September 19, 2008 8:59 AM
To: dakota-truck@dakota-truck.net
Subject: DML: RE: RE: RE: RE: RE: RE: Cold engine puts out more hp/tq...
Yup...while yes it can, it depends on quite a few other conditions - not
just intake air temp.
(RPM/Max RPM) x (MAP Baro) x (TPS x ECT x IAT x Sensed Battery Voltage x
LTFT) x (Upstream O2) x (STFT x LTFT) = PW
That's the formula. The ignition timing is also affected by IAT (but not
just by itself) so engine and weather conditions do apply. Higher/Lower
pressure, engine coolant temp, engine rpm, battery voltage, throttle
position...so you're trying to tell me that they don't matter??? What about
what the O2's read - think about those variables and how the PCM reacts too.
Fuel mileage is dependent on a lot of variables - yes...the difference in
between a 30 degree outside ambient and 90 degree outside ambient will
affect mileage slightly, but again...pcm calculations need to be figured
out.
- Bernd
-----Original Message-----
From: Brian [mailto:hskr@cox.net]
Sent: Friday, September 19, 2008 7:31 AM
To: dakota-truck@dakota-truck.net
Subject: DML: RE: RE: RE: RE: RE: Cold engine puts out more hp/tq...
Yes, and you even mentioned weather, which is what you are tricking the
computer into thinking is changing with the IAT mod. You can't honestly sit
there and say that tricking the PCM into thinking there is a colder intake
charge doesn't affect gas mileage.
brian cropp
-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Bernd D.
Ratsch
Sent: Friday, September 19, 2008 6:31 AM
To: dakota-truck@dakota-truck.net
Subject: DML: RE: RE: RE: RE: Cold engine puts out more hp/tq...
I can watch the fuel mileage change just by pressing the accelerator pedal
slightly (as the cruise does) on level ground. Sorry to say but conditions
do apply - look up the injector pulse-width formula and you'll understand.
- Bernd
-----Original Message-----
From: Brian [mailto:hskr@cox.net]
Sent: Thursday, September 18, 2008 10:40 PM
To: dakota-truck@dakota-truck.net
Subject: DML: RE: RE: RE: Cold engine puts out more hp/tq...
Hmm, lets see, the computer adjust the amount of fuel based on the intake
air temp, which is why there is an intake air temp sensor. Colder air
contains more oxygen and requires more fuel. You trick the computer into
thinking the air is colder than it really is, then you will use more fuel.
It's not rocket science. I used to have one of the adjustable IAT boxes
from speedtweaks(wasn't that you Bernd??) And on straight level ground with
the cruise control set, I could watch the fuel mileage change on my overhead
console as I turned the knob. I don't care what the conditions are, or what
type of fuel you are using. If the computer thinks there is colder air
going into the engine than there actually is, it will throw more fuel at it.
Especially when accelerating.
brian cropp
-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Bernd D.
Ratsch
Sent: Thursday, September 18, 2008 9:36 PM
To: dakota-truck@dakota-truck.net
Subject: DML: RE: RE: Cold engine puts out more hp/tq...
Not necessarily - it depends on the driving conditions, weather (temp
mainly), and fuel blend.
- Bernd
-----Original Message-----
From: Brian [mailto:hskr@cox.net]
Sent: Thursday, September 18, 2008 8:23 PM
To: dakota-truck@dakota-truck.net
Subject: DML: RE: Cold engine puts out more hp/tq...
Your gas mileage will suffer noticeably as well if you do any of the IAT
sensor mods mentioned.
brian cropp
-----Original Message-----
From: owner-dakota-truck@bent.twistedbits.net
[mailto:owner-dakota-truck@bent.twistedbits.net] On Behalf Of Dan Kramarsky
Sent: Thursday, September 18, 2008 6:49 PM
To: dakota-truck@dakota-truck.net
Subject: DML: Cold engine puts out more hp/tq...
DMLers,
I have notice that within the first 3 to 4 minutes of driving in the
morning, my truck is real neck snapper!! lol. It very apparent that I
get about 10 to 15 more HP within the first 4 minutes of driving the
vehicle after it has rested for several hours.
Is this due to PCM being 'open loop' mode until engine reaches operating
temperature and then switches to 'closed loop' mode?
Any way to get that first 5 minute performance... all the time ?
Dan K.
Vehicle 1: 1992 Dodge Dakota Club Cab LE Color: Two-tone silver Engine:
5.2L EFI Mods: March pullies, K&N Filter
Photo: http://static.flickr.com/42/84856795_c18903d10f.jpg
Vehicle 2: 1993 Ford Crown Victoria LX Color: White Engine: 4.6L EFI
Mods: none yet.
Photo: http://farm4.static.flickr.com/3098/2726734706_3f511ec702.jpg
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