View Full Version : Running lean, reasons, log...
lswing
April 8th, 2013, 00:29
So I'm running lean according to my lambda's at least. Now this log is on a cooler day, with w/m backed off (spray starts at 9 and full by 15psi), and fueling backed off from 7% to 6% under load, plus 1.5psi extra boost. When on the dyno last summer, with more w/m and 7% fuel, and 1.5psi less boost, had a 12.5 afr under full throttle.
You'll see I'm not even hitting 2bar (14.7psi), yet still lean, but plenty of timing. So...running lean because of the extra timing? (more fuel being burnt)....or the w/m mix? What I need to check again are the egt's, because even with this lean condition they could be decent due to the w/m.
Car feels great, like a rocket. But to compare, look at the log I just posted from G2's car, with no w/m or extra fueling added, and more boost. Yet his mix looks nice and rich. I assume this is because of the reduced timing? Now timing is power, and I put down good numbers on the dyno, I'm just wondered why I seem to run lean and G2 is rich with ~3psi more boost.
<tbody>
Engine Speed
Throttle Valve Angle
Ignition
Lambda Control
Lambda Control
Boost Pressure
Boost Pressure
(G28)
Timing Angle
Bank 1 (actual)
Bank 2 (actual)
(specified)
(actual)
/min
%
°BTDC
V
V
mbar
mbar
2600
23.1
32.3
0.71
0.695
1380
1060
2640
27.1
32.3
0.64
0.74
1430
1090
2680
59.2
30
0.06
0.085
1500
1130
2720
84.3
27.8
0.625
0.73
1520
1190
2720
94.1
26.3
0.07
0.56
1550
1260
2760
98
24.8
0.07
0.695
1550
1330
2800
98.4
23.3
0.07
0.08
1550
1390
2880
100
18
0.135
0.175
1550
1470
2920
100
16.5
0.74
0.765
1550
1530
2920
100
13.5
0.75
0.78
1550
1580
3000
100
15
0.755
0.76
1560
1620
3040
100
13.5
0.7
0.77
1580
1630
3080
100
13.5
0.745
0.78
1610
1640
3160
100
12.8
0.755
0.795
1630
1640
3160
100
12.8
0.745
0.79
1660
1620
3240
100
12.8
0.77
0.8
1690
1610
3280
99.6
13.5
0.77
0.79
1700
1610
3320
99.6
14.3
0.77
0.805
1720
1610
3360
100
14.3
0.77
0.805
1760
1630
3400
100
14.3
0.77
0.81
1790
1660
3480
100
13.5
0.785
0.79
1810
1700
3520
100
12
0.77
0.805
1820
1740
3600
100
12.8
0.765
0.805
1830
1790
3640
100
12
0.77
0.795
1850
1830
3680
100
10.5
0.765
0.79
1860
1860
3720
100
10.5
0.765
0.775
1880
1890
3800
100
10.5
0.775
0.775
1890
1920
3840
100
10.5
0.755
0.755
1900
1940
3880
100
9
0.78
0.775
1900
1950
3960
99.6
9.8
0.775
0.78
1920
1960
4000
100
9.8
0.765
0.79
1930
1940
4080
100
9
0.77
0.795
1930
1940
4120
100
8.3
0.76
0.785
1930
1940
4160
100
9.8
0.76
0.79
1940
1920
4200
100
9
0.78
0.785
1940
1930
4240
100
9
0.765
0.78
1940
1910
4360
100
9
0.745
0.785
1950
1890
4400
100
9
0.74
0.785
1950
1910
4440
100
9
0.745
0.785
1950
1900
4480
100
9
0.73
0.785
1950
1880
4560
100
8.3
0.74
0.785
1950
1890
4600
100
9
0.74
0.785
1950
1890
4640
100
9
0.74
0.79
1940
1890
4720
99.6
8.3
0.745
0.79
1940
1890
4760
100
8.3
0.765
0.8
1920
1870
4800
100
9.8
0.77
0.81
1890
1860
4840
100
9
0.775
0.8
1870
1870
4920
100
8.3
0.785
0.8
1850
1870
5000
100
9
0.79
0.805
1840
1870
5040
100
9
0.785
0.8
1830
1850
5080
100
10.5
0.79
0.8
1820
1850
5160
100
10.5
0.785
0.81
1810
1830
5240
99.6
10.5
0.775
0.81
1810
1810
5280
100
11.3
0.78
0.81
1800
1790
5320
100
11.3
0.785
0.81
1790
1780
5400
99.6
12.8
0.785
0.81
1780
1760
5440
100
12.8
0.8
0.805
1770
1750
5520
100
12.8
0.785
0.81
1770
1740
5560
100
15.8
0.78
0.805
1770
1730
5600
99.2
15.8
0.785
0.81
1770
1710
5680
100
17.3
0.77
0.8
1770
1710
5720
99.6
15
0.77
0.815
1780
1720
5760
100
17.3
0.78
0.805
1780
1730
5800
100
15.8
0.785
0.795
1780
1720
5880
100
19.5
0.785
0.8
1770
1720
5920
100
19.5
0.77
0.81
1780
1720
5960
100
18
0.765
0.8
1780
1730
6000
100
16.5
0.77
0.805
1770
1750
6040
100
18
0.785
0.8
1770
1760
6120
99.6
16.5
0.78
0.81
1760
1760
6160
100
19.5
0.78
0.805
1750
1770
6200
100
17.3
0.785
0.81
1750
1750
</tbody>
4everRS
April 8th, 2013, 03:15
Post the specified lambda.
lswing
April 8th, 2013, 05:17
Specified is close, means? Will post soon, thanks!
lswing
April 8th, 2013, 07:29
Specified vs Actual lambda...
<tbody>
Engine Speed
Ignition
Lambda Control
Lambda Control
Lambda Control
Lambda Control
Boost Pressure
Boost Pressure
(G28)
Timing Angle
Bank 1 (actual)
Bank 1 (specified)
Bank 2 (actual)
Bank 2 (specified)
(specified)
(actual)
/min
°BTDC
V
V
V
V
mbar
mbar
2880
18
0.135
0.15
0.175
0.1
1550
1470
2920
16.5
0.74
0.72
0.765
0.73
1550
1530
2920
13.5
0.75
0.76
0.78
0.775
1550
1580
3000
15
0.755
0.75
0.76
0.76
1560
1620
3040
13.5
0.7
0.74
0.77
0.745
1580
1630
3080
13.5
0.745
0.77
0.78
0.765
1610
1640
3160
12.8
0.755
0.78
0.795
0.775
1630
1640
3160
12.8
0.745
0.785
0.79
0.77
1660
1620
3240
12.8
0.77
0.785
0.8
0.77
1690
1610
3280
13.5
0.77
0.795
0.79
0.775
1700
1610
3320
14.3
0.77
0.785
0.805
0.79
1720
1610
3360
14.3
0.77
0.79
0.805
0.795
1760
1630
3400
14.3
0.77
0.79
0.81
0.79
1790
1660
3480
13.5
0.785
0.79
0.79
0.795
1810
1700
3520
12
0.77
0.795
0.805
0.79
1820
1740
3600
12.8
0.765
0.79
0.805
0.79
1830
1790
3640
12
0.77
0.785
0.795
0.785
1850
1830
3680
10.5
0.765
0.775
0.79
0.775
1860
1860
3720
10.5
0.765
0.75
0.775
0.785
1880
1890
3800
10.5
0.775
0.745
0.775
0.785
1890
1920
3840
10.5
0.755
0.765
0.755
0.775
1900
1940
3880
9
0.78
0.76
0.775
0.78
1900
1950
3960
9.8
0.775
0.75
0.78
0.785
1920
1960
4000
9.8
0.765
0.78
0.79
0.785
1930
1940
4080
9
0.77
0.78
0.795
0.785
1930
1940
4120
8.3
0.76
0.765
0.785
0.78
1930
1940
4160
9.8
0.76
0.79
0.79
0.765
1940
1920
4200
9
0.78
0.78
0.785
0.79
1940
1930
4240
9
0.765
0.755
0.78
0.785
1940
1910
4360
9
0.745
0.785
0.785
0.775
1950
1890
4400
9
0.74
0.78
0.785
0.75
1950
1910
4440
9
0.745
0.77
0.785
0.755
1950
1900
4480
9
0.73
0.765
0.785
0.735
1950
1880
4560
8.3
0.74
0.755
0.785
0.75
1950
1890
4600
9
0.74
0.775
0.785
0.765
1950
1890
4640
9
0.74
0.78
0.79
0.745
1940
1890
4720
8.3
0.745
0.785
0.79
0.75
1940
1890
4760
8.3
0.765
0.8
0.8
0.765
1920
1870
4800
9.8
0.77
0.805
0.81
0.785
1890
1860
4840
9
0.775
0.795
0.8
0.79
1870
1870
4920
8.3
0.785
0.785
0.8
0.795
1850
1870
5000
9
0.79
0.805
0.805
0.805
1840
1870
5040
9
0.785
0.8
0.8
0.8
1830
1850
5080
10.5
0.79
0.79
0.8
0.805
1820
1850
5160
10.5
0.785
0.81
0.81
0.81
1810
1830
5240
10.5
0.775
0.8
0.81
0.79
1810
1810
5280
11.3
0.78
0.805
0.81
0.79
1800
1790
5320
11.3
0.785
0.81
0.81
0.8
1790
1780
5400
12.8
0.785
0.805
0.81
0.805
1780
1760
5440
12.8
0.8
0.805
0.805
0.82
1770
1750
5520
12.8
0.785
0.81
0.81
0.805
1770
1740
5560
15.8
0.78
0.805
0.805
0.805
1770
1730
5600
15.8
0.785
0.8
0.81
0.8
1770
1710
5680
17.3
0.77
0.805
0.8
0.795
1770
1710
5720
15
0.77
0.8
0.815
0.79
1780
1720
5760
17.3
0.78
0.805
0.805
0.805
1780
1730
5800
15.8
0.785
0.79
0.795
0.8
1780
1720
5880
19.5
0.785
0.8
0.8
0.805
1770
1720
5920
19.5
0.77
0.815
0.81
0.79
1780
1720
5960
18
0.765
0.8
0.8
0.79
1780
1730
6000
16.5
0.77
0.8
0.805
0.79
1770
1750
6040
18
0.785
0.815
0.8
0.805
1770
1760
6120
16.5
0.78
0.815
0.81
0.8
1760
1760
</tbody>
lswing
April 8th, 2013, 17:05
I know I've gone through some of this before, open/closed loop difference. RossTech wiki is saying lower lambda value = richer mix. So my ecu setting for extra fuel is driving the requested number down? I've felt like the car has been a bit rich with it bogging in lower rpms...
If Lambda is less than 1.0, then there is a surplus of fuel and the engine is running rich. It should be noted that the ratios are mass-based, not volume-based.
However, when we need acceleration, the mixture gets richer. Why? Maximum power is made between 0.85 to 0.95 Lambda (12.5 to 14.0 A/F with iso-octane).
KWest
April 8th, 2013, 18:02
What is Lambda?
Lambda is a measure for the mass air to fuel ratio (AFR) present during combustion. When exactly enough fuel is combined with the available free oxygen, the mixture is chemically balanced and is called stoichiometric.
Lambda = 1 —stoichiometric mixture
Lambda < 1 —mixture is rich, excess fuel present
Lambda > 1 —mixture is lean, excess air present
The amount of air that is needed depends on the type of fuel used. In the case of gasoline/petrol, a stoichiometric mixture consists of an air to fuel ratio of 14.7 to 1. For different fuel, different ratios apply.
Narrowband Lambda
Narrowband Lambda is a measurement method where the AFR range is limited from 14:1 to 15.4:1. The sensor reading switches very sharply between the thresholds of lean and rich areas, providing a signal which indicates either a rich or a lean mixture but not to what degree.
This works well in controlling an engine for emissions, however, the limited range makes narrowband Lambda unsuitable for accurate tuning.
Wideband Lambda
Wideband Lambda sensors are designed to give an exact reading of Lambda. This is particularly useful when the precise mixture needs to be known in order to tune the engine for optimum power. The measuring range can span from 0.7 to 32 Lambda for a 5 wire sensor type.
Wideband Lambda sensors use sophisticated controls, as the temperature change needs to be taken into account to be accurate.
There are two concepts for measuring wideband Lambda:
4 Wire Wideband Lambda Sensor
This technology takes advantage of the fact that the sensor's voltage output is based on not only the oxygen differential between the exhaust pipe and atmosphere, but also on the temperature of the sensor itself. Sensor impedance varies with temperature, so not only the sensor voltage, but also the sensor impedance needs to be measured. Systems which do not use at least four wires typically have errors in displayed Lambda as high as 8 percent!
5 Wire Wideband Lambda Sensor
This newer technology determines the air fuel ratio of an engine by measuring Lambda sensor voltage output and the current required to hold the sensor voltage output constant. This method offers increased speed and accuracy over the older 4 wire sensor technology.
Tuning with Lambda
The tuning objective dictates the target Lambda. Typical gasoline/petrol engines produce
peak power at Lambda between 0.84 and 0.90
best economy at Lambda equal to 1.05
optimal emissions at Lambda slightly lower than 1
Being that our cars have narrow band sensors there is no way to accurately tune with it, outside of the 14:1-15.4:1 range the sensor is almost unless. Given sensor ageing and tolerance the only thing your numbers say is that you are richer then 14:1. You can take the fact that your actual and specified track each other so things are as they should be. If you are worried about it Innovative LC-1's are a great tuning tool, again you have to watch the sensor drift/response time. On my racebike with VP U4.4 the sensors would only last 1 weekend, now with Shell URT105 I can get 2-3 weekend before the drift/response gets bad.
From the stock/tuned maps I have looked at under high load most request .80-.84 Lambda. Rich is safe, especially when it comes to street driven cars. When you are trying to extract that last couple hp and save that .2mpg in a race car/bike then you tune towards peak lean torque.
lswing
April 8th, 2013, 18:17
Gotcha. Seems like leaning towards the EGT's will be a better focus. I did get on a dyno and wideband O2 last summer, 12.5/1, perfect all through full boost. Now that it's cool the engine does not want all that fuel that I was dumping into it this summer, plus my boost is lower. I don't flog it too much, just looking for the optimal seasonal power. I feel good with my summer settings as that's what I tuned for last year, and kept great power due to the w/m. Thanks!
4everRS
April 8th, 2013, 18:49
Keep in mind the difference between lambda "value" and lambda "voltage". The logs are not value. They are voltage. Higher is richer.
Your logs are a bit lean. I have no experience in Revo. I was going to give you a default answer of "your tune is requesting a lean mixture" but you have done some work with fueling software to change things.
I might try to add a little more fuel with your software and do another log.
.82 to .86 lambda "voltage" would be ideal.
lswing
April 8th, 2013, 19:03
Thanks, I thought I was fudging the value/voltage deal.
All I did this time was reduce fuel from 7 to 6%, upped boost 1.5psi, still not even hitting 15psi.
Car was bogging down way to much around 3k rpms, was not doing that last summer.
Is certainly peppier now!...but also leaner than I'd like. I'm running extra timing, and that was pulling me off the line nice in the warm days, doesn't seem to like the mix with this cool/wet weather...
KWest
April 8th, 2013, 22:52
Narrow band sensors output curve changes with sensor temperature outside the normal 14:1-15.4:1 range. So unless you know the EGT and the calibration curve for the sensor using its reading outside its working range is pointless.
EGT is a good overall gauge if an engine is operating correct, however ignition timing has a bigger affect on EGT then a lean mixture. A super rich mixture with retarded timing will have a higher EGT than a lean mixture with optimal timing.
Are you adjusting the overall fuel (CH.10) or load based fuelling (CH.2/3)?
**** I know being a new guy with no posts gives me zero street cred around here, but I'm not a newbie when it comes to reverse engineering ECU's or tuning.
lswing
April 9th, 2013, 01:31
Thanks for the info. It's always seemed like a battle of too hot and lean. I had it dialed in nice last summer, good dose of w/m, fuel, good egt, lambda, boost.
This spring it's just been bogged down, so trying to find that sweet spot for the cooler temps. I swear I'm not boosting as high, and with the cool air the engine hasn't been excited about getting a big dose of w/m fuel at 3k or below, fine above that. So I bumped up boost and got rid of some fuel.
What are your thoughts on "optimal timing"? Timing is power, so more is better as long as you don't induce knock due to pre-det with the cylinder open right. I'm hoping to get away with extra timing by adding the w/m to boost octane and cool the air, control the explosion. But I've also added extra fuel to try and keep the heat down and have enough to burn. I need to check EGT's, will in a few days...
**** I know being a new guy with no posts gives me zero street cred around here, but I'm not a newbie when it comes to reverse engineering ECU's or tuning.
I'd like to think it's the content that matters, not the post count.
By all means from what I'm seeing, welcome aboard. Not that it matters (much), I'm ASE Master Certified, years (uh, decades, now) of performance work and tuning, and own a repair shop. I know people like yourself, and fully welcome the insights and experience.
lswing, speaking from a seat of the pants perspective, had we been on a "customer complaint" test run, would normaly check some of the hard parts to rule them out- more tune-up related maybe?...the hesitation was reasonably apparent. Might be worth doing a fuel pressure leak down test.
When I got the (my) car was surprised at the meager sized fuel filter compared to all other Audi's and German cars we service. Thankfully it's cheap to replace and it will be a yearly event on my rig. I was suprised my car ran so well and sorta disappointed too (!). Not much to be had in terms of improvements it seems.
KWest is spot on about too much fuel and not enough timing (ign. and/or cam) drastically increasing EGT's-- been there done that on my Callaway Scirocco about 17+ years ago.
Your timing looks great, but can't speak to what the ideal setting is for this engine....(but would like to). VERY curious about EGT's now.
That's all this sleep deprived brain can come up with for now.
lswing
April 12th, 2013, 01:37
Bumped up the water meth some, 10 degrees warmer outside...took egt also, same boost.
<tbody>
Engine Speed
Throttle Valve Angle
Ignition
Lambda Control
Lambda Control
Lambda Control
Lambda Control
Exhaust Gas
Exhaust Gas
(G28)
Timing Angle
Bank 1 (actual)
Bank 1 (specified)
Bank 2 (actual)
Bank 2 (specified)
Temp. Bank 1
Temp. Bank 2
/min
%
°BTDC
V
V
V
V
°C
°C
2800
22.7
32.3
0.685
0.59
0.61
0.16
515
515
2800
25.5
30.8
0.705
0.325
0.14
0.51
515
515
2840
27.8
30
0.72
0.085
0.1
0.695
515
515
2880
30.2
28.5
0.325
0.105
0.13
0.585
520
515
2920
48.6
28.5
0.075
0.14
0.325
0.075
520
520
2960
82.4
26.3
0.1
0.235
0.71
0.07
520
520
2960
92.9
25.5
0.755
0.73
0.735
0.71
520
520
3040
97.3
22.5
0.705
0.715
0.735
0.705
525
520
3080
98.8
16.5
0.53
0.715
0.75
0.615
525
525
3120
99.6
18
0.095
0.7
0.71
0.105
530
525
3160
100
14.3
0.085
0.28
0.09
0.085
530
530
3200
100
16.5
0.465
0.145
0.485
0.13
535
530
3240
100
14.3
0.73
0.17
0.595
0.675
535
535
3280
100
13.5
0.065
0.2
0.395
0.075
540
535
3360
100
9
0.06
0.085
0.25
0.06
545
540
3400
99.6
12.8
0.07
0.38
0.65
0.065
545
540
3440
99.6
11.3
0.075
0.685
0.74
0.1
545
545
3480
100
6.8
0.195
0.715
0.755
0.12
550
545
3520
100
6.8
0.625
0.74
0.74
0.27
555
550
3560
100
5.3
0.605
0.755
0.775
0.265
560
555
3640
100
8.3
0.705
0.76
0.795
0.675
565
560
3680
100
6.8
0.725
0.75
0.775
0.72
570
565
3760
100
6.8
0.72
0.735
0.78
0.695
580
570
3800
100
6.8
0.75
0.775
0.79
0.735
585
575
3880
100
4.5
0.755
0.755
0.785
0.75
590
580
3920
100
7.5
0.76
0.78
0.805
0.775
595
590
3960
100
7.5
0.765
0.785
0.805
0.78
605
595
4040
100
4.5
0.78
0.8
0.815
0.79
610
600
4080
100
6.8
0.785
0.805
0.82
0.795
620
610
4120
100
6.8
0.775
0.8
0.81
0.785
620
610
4200
100
4.5
0.795
0.805
0.81
0.8
630
620
4240
99.6
4.5
0.8
0.8
0.815
0.81
645
625
4280
100
6.8
0.785
0.8
0.81
0.795
655
630
4360
100
4.5
0.78
0.805
0.82
0.795
660
645
4400
100
6.8
0.775
0.8
0.82
0.8
670
655
4440
100
3.8
0.785
0.81
0.815
0.805
680
665
4480
100
6.8
0.765
0.8
0.81
0.785
685
670
4560
100
6
0.785
0.815
0.82
0.81
695
680
4600
100
6.8
0.725
0.805
0.815
0.745
705
690
4640
100
4.5
0.77
0.81
0.815
0.785
710
695
4720
100
6
0.78
0.805
0.81
0.79
720
705
4760
100
6
0.78
0.815
0.82
0.8
725
710
4840
99.6
6
0.79
0.83
0.835
0.805
735
720
4880
100
4.5
0.8
0.835
0.84
0.815
745
730
4920
100
4.5
0.795
0.83
0.835
0.815
750
735
5000
100
6.8
0.8
0.83
0.83
0.825
760
745
5040
100
6.8
0.805
0.83
0.83
0.82
770
755
5120
100
5.3
0.82
0.83
0.83
0.84
780
765
5160
100
6
0.805
0.825
0.825
0.82
785
770
5240
100
9
0.81
0.83
0.835
0.83
795
775
5280
100
6
0.815
0.84
0.83
0.83
800
785
5360
100
7.5
0.805
0.825
0.83
0.83
805
790
5400
100
10.5
0.82
0.835
0.83
0.84
810
795
5480
100
8.3
0.815
0.84
0.83
0.84
820
805
5520
100
9.8
0.81
0.83
0.825
0.835
830
810
5600
100
11.3
0.8
0.815
0.815
0.825
835
815
5640
100
10.5
0.805
0.825
0.82
0.83
835
820
5680
100
9.8
0.81
0.835
0.83
0.835
840
825
5720
100
9
0.79
0.82
0.825
0.82
845
830
</tbody>
lswing
April 12th, 2013, 02:45
I also did some logs with wm reduced by 75%, and they were not good. Timing pulled into negative, egt's were 50 higher, lambda even leaner, could feel it was off, and this is with "only" 14psi boost. Not enough fuel? Too much timing? I could turn the fuel up, but that seemed to bog it down. Baffled as it was dialed last summer...difference is car has new trans, pulled apart, and its now 50 here not 85...
KWest
April 12th, 2013, 03:44
Your thread got me in the mood to do some logs. I did some runs out in the country last evening, ambient air temp was about 2C. I was doing 2nd gear runs to get the temps up, hard brake then 3rd gear run. Attached is a 3rd gear run that I rolled into.
The most interesting thing is TargetAFRDriverRequest at part throttle, and then full throttle. Even under boost and part throttle the ECU is still trying for 1.0 lambda and full throttle is only .89 lambda. There is no question some more fuel will help everything except fuel mileage.
This was with a fresh tank of Shell 91, I have half a barrel of Shell URT105 that's too old to run in the bike so once this tank is done I'll pump it in and do a comparison run. I'm interested to see how big of a difference it will make in ignition corrections.
Sorry for the .xlsx, but I was 30k characters over the post limit and it will be easier to view all the data.
https://dl.dropboxusercontent.com/u/1097543/KWest.3rdGearBlast.xlsx
DHall1
April 12th, 2013, 05:08
Lou,
Sorry to see the issues crop back into the picture.
A couple of things. Go back to square one and clear the ecu. Disconnect battery or reset with vag. Then drive the car and perform some logs with your fuel trim set at the last value that produced good results.
Log to set a nice boost baseline and look at fuel.
Then dial in your fuel to get that voltage back to .84v
Then log to inspect the timing advance. Only after you have sorted boost then fuel do you play around with the timing. imho
Timing could be your "bog"
Post up more info on this bog and what your feeling. good luck
I also did some logs with wm reduced by 75%, and they were not good. Timing pulled into negative, egt's were 50 higher, lambda even leaner, could feel it was off, and this is with "only" 14psi boost. Not enough fuel? Too much timing? I could turn the fuel up, but that seemed to bog it down. Baffled as it was dialed last summer...difference is car has new trans, pulled apart, and its now 50 here not 85...
lswing
April 12th, 2013, 06:01
Kwest, tough to read, interesting though, you tuned? Thanks Dave, was just talking about that extra timing i'm running being too much. Going to dial that back a bit and give it a run, see what we got then look at clearing it out.
My random thought on this. Old trans would slip some allowing easier spooling on the engine at low rpms, new trans clutchs are tight, no slipping, more load on engine. Hmmm....
DHall1
April 12th, 2013, 07:31
On one of the above logs you were running alot more timing.
If you were lean and running that timing....ecu has already pulled timing due to detonation which could account for your feeling of bogging
You cant really make timing changes after the fact without clearing the ecu learned knock detection. Your timing has been pulled by the ecu already.
Got to clear the ecu then follow the steps with boost....fuel....then timing.
Kwest, tough to read, interesting though, you tuned? Thanks Dave, was just talking about that extra timing i'm running being too much. Going to dial that back a bit and give it a run, see what we got then look at clearing it out.
My random thought on this. Old trans would slip some allowing easier spooling on the engine at low rpms, new trans clutchs are tight, no slipping, more load on engine. Hmmm....
KWest
April 12th, 2013, 17:30
Kwest, tough to read, interesting though, you tuned?
Ya, its a bit tough to follow the numbers in excel, its easier to understand in a real data program with graphing.
Yes, the car was tuned by the original owner. I'm on the hunt for the original bin file so I can flash it myself.
G2
April 12th, 2013, 21:07
Had a chat with an old pro, regarding both the RS6 and of the issues.
This is general info and I've regurgitated to the best of my ability.
1. the small fuel filter needs to be replaced often, about every 6 months for tuned cars.
2. The fuel pump degrade with time and keeping a fresh one on board helps under high loads.
3. Using colder spark plugs helps. Keeping a close eye on the condition is important- replace often.
4. I was told 7* BTDC at max load is the safe limit, at least with 91 pump gas. The (advanced) timing doesn't cause high EGT's.
5. Lamda should be, I THINK he said .79v or higher is okay to prevent burned valves.
6. There are latency issues with the ECU and data ouput for logging purposes.
I have a newer fuel filter and plugs (colder heat range) and that could be directly related to the more stabile fueling and okay timing. I plan to replace the fuel pump, especially if/when I run into less than ideal AFR.
Seems my "technician spider senses" may be somewhere on the target at least with the hard parts.
DHall1
April 13th, 2013, 03:46
I like this list.
.79 is bare minimum.
Get them fuel filters changed.
Had a chat with an old pro, regarding both the RS6 and of the issues.
This is general info and I've regurgitated to the best of my ability.
1. the small fuel filter needs to be replaced often, about every 6 months for tuned cars.
2. The fuel pump degrade with time and keeping a fresh one on board helps under high loads.
3. Using colder spark plugs helps. Keeping a close eye on the condition is important- replace often.
4. I was told 7* BTDC at max load is the safe limit, at least with 91 pump gas. The (advanced) timing doesn't cause high EGT's.
5. Lamda should be, I THINK he said .79v or higher is okay to prevent burned valves.
6. There are latency issues with the ECU and data ouput for logging purposes.
I have a newer fuel filter and plugs (colder heat range) and that could be directly related to the more stabile fueling and okay timing. I plan to replace the fuel pump, especially if/when I run into less than ideal AFR.
Seems my "technician spider senses" may be somewhere on the target at least with the hard parts.