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16v has more power when motor is cold?
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So, the consensus is that cold engines DO have more torque than warm =
engines. I noticed this many years ago when I was motocrossing; my =
open-class two-strokes would pull hole shots when I fired them up just =
prior to the flag dropping (hand-on-helmet starts, for you young guys). =
If I started them 3-4 minutes before the start, I'd be in the middle of =
the pack at the first corner.
Now, how do we fool our engines into thinking they are cold?
Is it even possible? Maybe they JUST HAVE TO BE COLD! =20
larry
----- Original Message -----=20
From: Dan Smith=20
To: L F ; T. Reed ; scirocco-l@scirocco.org=20
Sent: Thursday, November 21, 2002 8:43 PM
Subject: Re: 16v has more power when motor is cold?
That was going to be my suggestion, although I notice weather makes a =
HUGE difference with my car and its acceleration as well. My car is =
happiest on clear sunny days in the low 60s. After it warms up (weather =
and/or car) it loses some of it's zip.
Dan
Could be that your tires are just not as grippy when they're cold??
:)
Seriously, I sometimes feel like my 16V pulls a little harder when =
it's cold, too.
=20
Larry
----- Original Message -----=20
From: T. Reed=20
To: scirocco-l@scirocco.org=20
Sent: Thursday, November 21, 2002 7:25 PM
Subject: 16v has more power when motor is cold?
Hey all,
Just got back from a drive tonight and I noticed that during the first =
2
minutes or so the car had kick ass power.. I mean, I was barely laying =
in
to the throttle .. probably just a touch over half way, and the tires =
were
chirping in 1st and 2nd without even trying. After the car was warmed
up I went over the same stretch of road and while it was still fast =
and
there was no "huge" reduction in power, I couldn't get the tires to =
chirp
again with the same amount of throttle. Both times I was just doing my
normal smooth declutching action.
I know that's not very scientific, but I'm feeling like my motor is
running "torquier" when it hasn't warmed up yet. Ambient air temp is =
about
50 F, but I can't imagine that cold vs. warm air could make that much =
of a
difference, besides.. my engine runs cold to begin with (I never get =
to
the LED on the water temp gauge)
I do have my mixture set to 4 mA +/- 1 mA.. Stock is 5 mA or 10 mA
depending on who you ask. This is a 2.0 16v with 1.8 head, BTW.
I've noticed that my idle bounces a bit until the car warms up. I've =
heard
that this can indicate a rich mixture, but I can't rememebr why.
I suspect that what might be happening is while the car is in open =
loop
mode, the mixture is not influenced by the O2 sensor and is going rich
because of my non-stock mechanical setting of the mixture screw. But
once the car warms up, the oxygen sensor bypasses the mechanical =
setting,
leaning out the mixture and causing me to loose power..
I replaced the sensor about 1.5 years ago with a universal bosch =
sensor
and spliced the wires in to the original harness.
So I'm wondering:
- what is the difference between euro mechanical CIS for 16v's and our
CIS-E running in open loop mode? It seems to me like there should be =
no
difference.. in steady-state conditions the mixture is based =
completely
off of the mechanical adjust screw when in open loop mode.. it =
should
be possible to force the car in to open loop (by disconnecting the =
o2
sensor) and tune the screw to keep something just a little richer =
than
stoich. This would also preserve all the warm-up and acceleration
enrichment features of CIS-E (assuming they normally operate when in
open loop)
- has anyone tried placing a resistor in line with the oxygen sensor =
to
cause its output voltage to be divided between the resistor and the
computer, effectively making the computer "see" a lower voltage =
(which
corresponds to a leaner mixture) and thus causing it to richen the
mixture on its own? It seems like this would work.. if it did then =
you
could put a potentiometer in line and tune the mixture to your =
liking,
electrically.
I think I might try the latter, and borrow my friend's homemade air =
fuel
meter that hooks to the o2 sensor and see if putting resistance inline
is indeed effective in changing the mixture. First, though.. I'll need =
to
put an ammeter inline with the o2 sensor and see how much current is =
going
through the circuit so I can determine what range of resistance is =
needed.
Anyway, I just thought I'd share my ideas about this since I know =
CIS-E is
notorious for leaning things out in the name of fuel economy.
I've thought about buying one of those euro CIS setups for $300-ish =
but in
my opinion there is nothing mechanically wrong with the CIS-E I =
already
have.. its more than capable of delivering the amount of fuel (and the
proper amount, at that).. so why junk it? As an electrical engineering
student I'm inclined to find an electrical (read: cheap; components =
cost
just pennies and are readily available) solution that uses the =
existing
mechanical parts and sensors to accomplish the same goal.
-Toby
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<DIV><FONT face=3DArial size=3D2>So, the consensus is that cold engines =
DO have more=20
torque than warm engines. I noticed this many years ago when I was =
motocrossing; my open-class two-strokes would pull hole shots when =
I fired=20
them up just prior to the flag dropping (hand-on-helmet starts, for you =
young=20
guys). If I started them 3-4 minutes before the start, I'd be in =
the=20
middle of the pack at the first corner.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Now, how do we fool our engines into =
thinking they=20
are cold?</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Is it even possible? Maybe they =
JUST HAVE TO=20
BE COLD! </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>larry</FONT></DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: =
0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A href=3D"mailto:sad_rocc@veedub.com"; title=3Dsad_rocc@veedub.com>Dan =
Smith</A>=20
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
href=3D"mailto:rocco16v@netzero.net"=20
title=3Drocco16v@netzero.net>L F</A> ; <A =
href=3D"mailto:treed2@u.washington.edu"=20
title=3Dtreed2@u.washington.edu>T. Reed</A> ; <A=20
href=3D"mailto:scirocco-l@scirocco.org"=20
title=3Dscirocco-l@scirocco.org>scirocco-l@scirocco.org</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Thursday, November 21, =
2002 8:43=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: 16v has more power =
when=20
motor is cold?</DIV>
<DIV><BR></DIV>That was going to be my suggestion, although I notice =
weather=20
makes a HUGE difference with my car and its acceleration as well. My =
car is=20
happiest on clear sunny days in the low 60s. After it warms up =
(weather and/or=20
car) it loses some of it's zip.<BR><BR>Dan<BR><BR>Could be that your =
tires are=20
just not as grippy when they're cold??<BR>:)<BR>Seriously, I sometimes =
feel=20
like my 16V pulls a little harder when it's cold,=20
too.<BR> <BR>Larry<BR>----- Original Message ----- <BR>From: T. =
Reed=20
<BR>To: <A =
href=3D"mailto:scirocco-l@scirocco.org";>scirocco-l@scirocco.org</A>=20
<BR>Sent: Thursday, November 21, 2002 7:25 PM<BR>Subject: 16v has more =
power=20
when motor is cold?<BR><BR><BR>Hey all,<BR><BR>Just got back from a =
drive=20
tonight and I noticed that during the first 2<BR>minutes or so the car =
had=20
kick ass power.. I mean, I was barely laying in<BR>to the throttle .. =
probably=20
just a touch over half way, and the tires were<BR>chirping in 1st and =
2nd=20
without even trying. After the car was warmed<BR>up I went over the =
same=20
stretch of road and while it was still fast and<BR>there was no "huge" =
reduction in power, I couldn't get the tires to chirp<BR>again with =
the same=20
amount of throttle. Both times I was just doing my<BR>normal smooth=20
declutching action.<BR><BR>I know that's not very scientific, but I'm =
feeling=20
like my motor is<BR>running "torquier" when it hasn't warmed up yet. =
Ambient=20
air temp is about<BR>50 F, but I can't imagine that cold vs. warm air =
could=20
make that much of a<BR>difference, besides.. my engine runs cold to =
begin with=20
(I never get to<BR>the LED on the water temp gauge)<BR><BR>I do have =
my=20
mixture set to 4 mA +/- 1 mA.. Stock is 5 mA or 10 mA<BR>depending on =
who you=20
ask. This is a 2.0 16v with 1.8 head, BTW.<BR><BR>I've noticed that my =
idle=20
bounces a bit until the car warms up. I've heard<BR>that this can =
indicate a=20
rich mixture, but I can't rememebr why.<BR><BR>I suspect that what =
might be=20
happening is while the car is in open loop<BR>mode, the mixture is not =
influenced by the O2 sensor and is going rich<BR>because of my =
non-stock=20
mechanical setting of the mixture screw. But<BR>once the car warms up, =
the=20
oxygen sensor bypasses the mechanical setting,<BR>leaning out the =
mixture and=20
causing me to loose power..<BR><BR>I replaced the sensor about 1.5 =
years ago=20
with a universal bosch sensor<BR>and spliced the wires in to the =
original=20
harness.<BR><BR>So I'm wondering:<BR><BR>- what is the difference =
between euro=20
mechanical CIS for 16v's and our<BR> CIS-E running in open loop =
mode? It=20
seems to me like there should be no<BR> difference.. in =
steady-state=20
conditions the mixture is based completely<BR> off of the =
mechanical=20
adjust screw when in open loop mode.. it should<BR> be possible =
to force=20
the car in to open loop (by disconnecting the o2<BR> sensor) and =
tune=20
the screw to keep something just a little richer than<BR> =
stoich. This=20
would also preserve all the warm-up and acceleration<BR> =
enrichment=20
features of CIS-E (assuming they normally operate when in<BR> =
open=20
loop)<BR><BR>- has anyone tried placing a resistor in line with the =
oxygen=20
sensor to<BR> cause its output voltage to be divided between the =
resistor and the<BR> computer, effectively making the computer =
"see" a=20
lower voltage (which<BR> corresponds to a leaner mixture) and =
thus=20
causing it to richen the<BR> mixture on its own? It seems like =
this=20
would work.. if it did then you<BR> could put a potentiometer in =
line=20
and tune the mixture to your liking,<BR> electrically.<BR><BR>I =
think I=20
might try the latter, and borrow my friend's homemade air =
fuel<BR>meter that=20
hooks to the o2 sensor and see if putting resistance inline<BR>is =
indeed=20
effective in changing the mixture. First, though.. I'll need to<BR>put =
an=20
ammeter inline with the o2 sensor and see how much current is =
going<BR>through=20
the circuit so I can determine what range of resistance is=20
needed.<BR><BR>Anyway, I just thought I'd share my ideas about this =
since I=20
know CIS-E is<BR>notorious for leaning things out in the name of fuel=20
economy.<BR><BR>I've thought about buying one of those euro CIS setups =
for=20
$300-ish but in<BR>my opinion there is nothing mechanically wrong with =
the=20
CIS-E I already<BR>have.. its more than capable of delivering the =
amount of=20
fuel (and the<BR>proper amount, at that).. so why junk it? As an =
electrical=20
engineering<BR>student I'm inclined to find an electrical (read: =
cheap;=20
components cost<BR>just pennies and are readily available) solution =
that uses=20
the existing<BR>mechanical parts and sensors to accomplish the same=20
=
goal.<BR><BR>-Toby<BR><BR><BR><BR><BR>___________________________________=
__________________________<BR>Sign=20
up for FREE email <A=20
href=3D"mailto:yourname@veedub.com";>yourname@veedub.com</A><BR>from <A =
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