OBD II article------------>very interesting (archive)

At 05:51 PM 1/30/99 -0500, Tom Peluso wrote:
>
>-> Sure.. lots of them.. BEYOND the fact that I have repeatedly said
>> that owners cannot reliably dyno an OBD-II upgrade because of the
>> adaption concerns (and no one seems to listen to me.. they just
>> keep wasting money.. and the dynojet operators keep making money)
>>
>How does one properly dyno an OBD-II upgrade?

It's called adaption.. simply put, the Siemens boxes in the
BMW 6 cylinder cars adapt under a much wider range than the
previous OBD-I.. and worst off YOU can't clear the adaption..

See, previous to OBD-II, adaptive information was stored in
battery backed SRAM. Unplug the DME to swap chips and woosh
all adaptive factors set to "nominal" (1 for mult. and 0 for add.)
Then came Kalifornia, and KARB, and OBD-II.. and EEPROM for
storage.. this means you can't just "erase" it anymore because
the last thing the DME does during shutdown is write the SRAM
locations to EEPROM.. and guess what the first thing it does is.

Yup... zero SRAM, run a galpat memory check, and reload the
needed ram locations from EEPROM.

The only way to clear the adaptive locations is via diagnostic
commands down the serial port (even desoldering the main
FLASH memory program store doesn't do it, because there is a
separate EEPROM elsewhere)

What's worse is the "quasi-tuners" out there who have no idea
how it all works, spouting nonsense..

Either you trust the person your buying it from, or don't
buy it. It really is like "Natural Flavors" in soda...

Either you trust the manufacturer, or you put the can back
on the shelf, because it's not easy to quantify the contents.

Now.. back to adaption.. since you can't clear it
you can't get a valid comparison.. want to try something..

Take your car.. OBD-II.. chipped or stock.. drive it one week
like a MADMAN and dyno it.. then drive it for another week
very meekly.. and dyno it.. compare the results.. and they
WILL NOT be anywhere NEAR the same.. and we didn't change the
car at ALL..

Exactly.. the car ADAPTED to different areas of the maps
and either enrichened or enleaned the overall mixture.

Now.. in whatever state the car is in, you can be rather
assured that ON AVERAGE the chipped car is making significantly
more power than the stock car.

Adaption works like this.. at lower loads and rpms it watches
the AVERAGE correction (realize we swing rich and lean of
stoichiometric continuously, except for WOT)... and it adds or
subtracts a bit of fuel until the low speed fuel mixture is
swinging evenly around Lambda = 1.0 / AFR 14.7:1..

Now as the rev range increases.. we switch to a multiplicative
correction which adjusts (if you will) the SLOPE of the fuel
curve by multiplying the STORED values by a factor (based on 1.00)

Depending upon how good the manufacturer tuned the low end and lower
midrange, the environmental conditions, the fuel you are using,
and the flavor of soda I have in my fridge (*grin*) .. well really
what AREAS of that lower speed area you are in most of the time
during the drive cycles.. that determines WHAT those two magic
numbers will be.

The kicker.. and bummer.. is that even though lambda control isn't
active, and adaption isn't HAPPENING at high throttle angles, those
two numbers ARE STILL USED IN THE CALCULATION regardless as an
"overall correction" to fueling.

So.. let's say that at 20% throttle and 3000 rpms the manufacturer
is a bit rich.. the system adapts lean.. if you drove at very light
load/throttle for a while at 3000.. you might see your peak HP
drop 10HP on the dyno.. once the car adapts

Conversely, let's say the manufacturer is a bit lean at 2000 and 50%
and you spend your week in LA traffic jams always gassing it in 4th
and not downshifting.. car goes rich.. now you dyno your car and
BOOM magic horsepower have appeared (well.. not really)

Simply put.. while any chip manufacturer can tell you that 90+% of the
time your chipped car will have more HP than the stock one, unless you
have cleared the adaption BOTH times when you run the cars you can't
quantify it at all.

PS: Know that this isn't something I'm pulling out of my butt, it's
as frustrating to me as it is to you, because to tune these cars
you disconnect all 4 sensors and then put the car into intentional
FAULTS to stop adaption.. which you then clear to 0 and 1 respectively
then tune.. then test.. and on it goes.

--------------------------------------------------------------------------------

Date: Sat, 30 Jan 1999
From: Land Shark
Subject: Re: [E36M3] RE: Jim C 2.8 dyno results (from Z3 list?)

>Okay, so if you drive your car gently all week, then it will adapt
>lean/rich based on how the engine is performing at low throttle.
>Then when you go to the track on saturday and stand on the throttle,
>it may be too lean or too rich depending upon how the engine is
>performing at WOT. Right?

>So, if you are going to the track in your daily driver, and you want
>it performing its best on Saturday, you may want to flog it during
>the week -- so the software is adapting to the engine at high
>throttle rather than at low throttle???? Right?

In practice, it's not something you can do reliably,
and that's the whole problem.. unless you have a bunch
of instrumentation on the car watching load and rpm and airflow
and such..

>P.S. Besides the lean/rich software, is there any other software that
>is adapting and affected by driving behavior?

--------------------------------------------------------------------------------

OBD-II Dyno Results - Z3 2.8
Date: Sat, 30 Jan 1999
From: "Michael J. Greto"
Subject: Jim C 2.8 dyno results (repost from Z3 message board)

Someone with a Z3 2.8 posted the following to the Z3 message board after
upgrading to Jim C. software. I think the Dinan intake is hurting and not
helping as I know people are getting much better results than this with
stock intake and exhaust. Also based on these tests it seems he has gotten
~30HP from the intake and exhaust, I know that is pure BS. Any other
comments?

>Well, I just returned from the dyno. My car is a 98 2.8 manual with the
>Dinan intake, Supersprint exhaust without the crimp and now with the new
>Jim C ECU. The run was made on a 248C dynojet using 92 octane fuel and a
>temp of app 20 degrees F. Here are my best numbers pre and post.
>PRE - 188.1hp at 5250rpms and 197 ft lbs at 4350 rpms.
>POST - 190.2 hp at 5250rpms and 200.6 ft lbs at 4000 rpms.
A total gain of only 2.1 hp and 3.6 ftlbs of torque.
Assuming 15% drivetrain losses 223.8 hp and 236 ftlbs. I don't understand
the poor showing post ECU other than the fact that modifications are never
cumilative and that I was able to gain most of the easy hp with the exhaust
and intake. I have never trusted hp numbers with ECU upgrades in non turbo
cars, and this only strengthens my doubts. How much more hp can you get by
maximizing for 3-5 octane points anyways? If anyone can post some personal
dyno numbers pre and post ECU, maybe then I'll be a believer. I also expect
that the other ECU's (Autothority, Dinan, etc) will fair just as well on the
dyno.
Would I do it again, maybe... but I'm a hp freak anyways. My butt dyno did
notice a slight improvement.

TORQUE HP
RPM pre post gain pre post gain
1600 152.3 156.7 +4.4 47.0 48.4 +1.4
1700 152.3 159.5 +5.2 50.9 52.4 +1.5
1800 160.9 162.4 +1.5 56.1 56.6 +0.5
1900 167.4 168.9 +2.5 61.4 62.1 +0.7
2000 167.4 172.4 +5.0 64.7 66.7 +2.0
2100 168.1 174.6 +6.5 68.3 71.0 +1.7
2200 171.7 178.3 +6.5 73.0 75.8 +2.8
2300 172.5 179.0 +6.5 76.8 79.7 +2.9
2400 168.1 175.3 +7.2 78.0 81.4 +3.4
2500 168.1 175.3 +7.2 81.4 84.8 +3.4
2600 171.7 177.5 +5.8 86.3 89.2 +2.9
2700 171.0 176.8 +5.8 89.4 92.3 +2.9
2800 171.0 176.8 +5.8 92.6 95.6 +3.0
2900 173.9 177.5 +3.6 97.7 99.8 +2.1
3000 176.8 180.4 +3.6 102.8 104.6 +1.8
3100 180.4 183.3 +2.9 108.0 110.0 +2.0
3200 183.3 186.9 +3.6 113.3 115.6 +2.3
3300 188.3 192.7 +4.4 120.3 122.8 +2.5
3400 189.8 194.1 +4.3 125.1 127.8 +2.7
3500 189.8 194.1 +4.3 128.4 131.4 +3.0
3600 189.1 194.1 +5.0 131.6 135.3 +3.7
3700 190.5 195.5 +5.0 136.5 140.2 +3.7
3800 193.4 198.4 +5.0 142.4 145.7 +3.3
3900 194.8 199.9 +5.1 147.1 150.7 +3.6
4000 195.6 200.6 +5.0 151.5 155.2 +3.7
4100 194.1 199.2 +5.1 154.1 157.8 +3.7
4200 191.9 197.8 +5.9 156.0 161.0 +5.0
4300 196.3 199.9 +3.6 163.1 166.4 +3.3
4400 195.6 199.9 +4.3 166.4 170.0 +3.6
4500 194.9 197.8 +2.9 169.7 172.1 +2.4
4600 194.2 196.2 +2.0 172.6 174.5 +1.9
4700 192.7 194.8 +1.5 175.2 177.3 +2.1
4800 192.7 193.4 +0.7 178.7 179.8 +1.1
4900 190.5 192.7 +2.2 180.3 182.7 +2.4
5000 189.8 191.3 +1.5 183.4 185.4 +2.0
5100 189.1 190.5 +1.4 186.9 187.9 +1.0
5200 186.2 187.6 +1.4 187.4 189.1 +1.7
5300 182.6 184.7 +2.1 187.4 189.7 +2.3
5400 178.2 180.4 +2.2 186.4 188.5 +2.1
5500 173.2 174.6 +1.4 184.2 185.9 +1.7
5600 164.5 169.6 +5.1 178.6 184.1 +5.5
5700 160.9 163.1 +2.2 177.3 180.2 +2.9
5800 154.4 157.3 +2.9 173.5 176.2 +2.7
5900 147.2 152.3 +5.1 167.7 173.7 +6.0
6000 145.7 150.1 +4.4 169.6 173.9 +4.3
As you see, at no point did the post curve dip under the pre curve and also
that the most notable gains were up to about 4400 rpms. ( also the worthless
gains above 5500 rpms ).

--------------------------------------------------------------------------------

Date: Sat, 30 Jan 1999
From: Land Shark
Subject: RE: Jim C 2.8 dyno results (from Z3 list?)

>Someone with a Z3 2.8 posted the following to the Z3 message board after
>upgrading to Jim C. software. I think the Dinan intake is hurting and not
>helping as I know people are getting much better results than this with
>stock intake and exhaust. Also based on these tests it seems he has gotten
>~30HP from the intake and exhaust, I know that is pure BS. Any other
>comments?

Sure.. lots of them.. BEYOND the fact that I have repeatedly said
that owners cannot reliably dyno an OBD-II upgrade because of the
adaption concerns (and no one seems to listen to me.. they just
keep wasting money.. and the dynojet operators keep making money)

What were the conditions of the original test.. because the
"stock" HP is showing around 227HP.. a bit much for a 2.8l
emissions motor rated out of the box at 190ish

Well, totally unrealistic.. because we KNOW the exhaust doesnt
do very much if anything on an OBD-II car besides sound.

What were the EXACT conditions of each test.. temp, pressure,
etc etc.. are these actual or corrected #'s..

Also, as had been made perfectly clear, the upgrade is designed
for a (very close to) stock vehicle.. not a modified one..

>I have never trusted hp numbers with ECU upgrades in non turbo
>cars, and this only strengthens my doubts.

("ECU upgrades" in turbo cars are a nobrainer.. you can raise boost
with a mechanical mod on the wastegate!)

Considering that they've been tested 100's of times and the large
majority of tests show good and real gains, you'd be contradicted
by the test data..

>I also expect that the other ECU's (Autothority, Dinan, etc) will
>fair just as well on the dyno.

Here, you'd not only be contradicted by the test data, but also
by the race results..

Anthony Cafik
Manny Kruger
Bob Tunnel
TC Kline
Carl Buckland
Todd Green
Dan Martinez
Will Turner
Ken Goldberg

Of course, Bob T's only a three time SCCA champion in Sharked M3's
(both OBD-1 and II!) so what would he know, right?!?

Then there's that unamed (well, Josh knows who it is, I forgot)
racer in the OBD-II M3 that was taking out SUPERCHARGED M3's with
his sharked M3.. somewhere in CO I think..

>As you see, at no point did the post curve dip under the pre curve and also
>that the most notable gains were up to about 4400 rpms. ( also the worthless
>gains above 5500 rpms ).

On a BMW, the revs above 5500 aren't there to LOOK AT.. they are there
to DRIVE..every day..

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