Dibilas CAI maf issue.
- Thread starter -pseudonymous-
- Start date
Interesting read that Dan. How much 'better' were your airflow readings after fitting the Dbilas Horace?
The stock oval pipe has a csa of pi*(2/2)*(3/2) = 4.71 square inches
New intake is 3 inc round = pi*1.5*1.5 = 7.07 square inches.
New pipe is 1.5 times larger than the original.
therefore readings in new maff tube will be lower than the original figures even if good gains are realised.
your lambda sensors are confirming this within your fuel trims.
In theory at least your new maff reading will equate to 209 * 1.5 =313g/sec which is unlikely, in old money.
But since the original maff sensor does not sit in the center of the tube, its under reading to begin with.
What does this all mean, not much without a dyno, but i would speak to the company about your findings.
Don't forget to post up before and after logs of vagcom 118 to see if the improved air flow can be seen affecting the duty cycle.
New intake is 3 inc round = pi*1.5*1.5 = 7.07 square inches.
New pipe is 1.5 times larger than the original.
therefore readings in new maff tube will be lower than the original figures even if good gains are realised.
your lambda sensors are confirming this within your fuel trims.
In theory at least your new maff reading will equate to 209 * 1.5 =313g/sec which is unlikely, in old money.
But since the original maff sensor does not sit in the center of the tube, its under reading to begin with.
What does this all mean, not much without a dyno, but i would speak to the company about your findings.
Don't forget to post up before and after logs of vagcom 118 to see if the improved air flow can be seen affecting the duty cycle.
Last edited:
Hey Willy here are a couple of logs of block 118.....
Stock Intake in 3rd gear:
Dbilas Intake in 3rd gear:
Stock Intake in 4th gear:
Dbilas Intake in 4th gear:
Obviously its not really a fair test as the logs were done on different days and the ambient temperatures were slightly warmer when i logged the stock intake. If i get time over the weekend i will try and get some better logs of both the stock and Dbilas intakes under the same conditions, but looking at the logs above there doesn't appear to be a great deal of difference between the two.
While i was out logging i thought i may aswell check my airflow readings and funnily enough they have since risen from 209g/s to 218g/s. I think next week i may knock up a little spacer for the maf tube to bring the maf more central and re-log it.
Dbilas airflow log in 3rd gear:
I've also noticed that since fitting the Dbilas intake my engine load values have gone to pot. Actual is no longer meeting the specified load whereas before fitting the intake it followed nicely. I assume this is down to false readings from the MAF sensor?
Stock Intake in 3rd gear:
Code:
'118
Engine Speed Intake Air Wastegate (N75) Boost Pressure
Temperature Duty Cycle (actual)
/min °C % mbar
1720 33 99.6 1010
1760 33 99.6 1060
1920 33 99.6 1170
2160 34 99.6 1290
2400 34 99.6 1430
2680 34 99.6 1650
2920 34 59.6 1930
3240 35 53.7 2190
3600 35 49.8 2250
3880 35 47.5 2120
4240 35 49.8 2070
4600 35 52.9 2110
4880 36 54.5 2130
5080 36 55.7 2160
5400 36 56.5 2140
5640 37 57.6 2130
5840 38 57.6 2120
6040 38 56.1 2040
6280 39 55.3 1950
6440 39 54.9 1930Dbilas Intake in 3rd gear:
Code:
'118
Engine Speed Intake Air Wastegate (N75) Boost Pressure
Temperature Duty Cycle (actual)
/min °C % mbar
1720 35 99.6 1050
1880 35 99.6 1170
2040 34 99.6 1260
2200 34 99.6 1350
2440 33 99.6 1510
2640 33 99.6 1710
2920 33 53.3 2030
3200 33 54.9 2280
3560 32 49 2240
3800 31 47.8 2090
4080 31 49 2080
4440 31 51.4 2120
4680 31 53.3 2110
4960 31 54.9 2130
5240 31 56.1 2140
5520 32 57.6 2120
5800 32 58 2110
6040 33 57.3 2040
6280 33 55.3 1980
6520 34 54.5 1910Stock Intake in 4th gear:
Code:
'118
Engine Speed Intake Air Wastegate (N75) Boost Pressure
Temperature Duty Cycle (actual)
/min °C % mbar
1960 39 99.6 1230
2040 38 99.6 1320
2160 38 99.6 1410
2280 38 99.6 1520
2360 38 99.6 1620
2480 37 99.6 1800
2680 37 57.3 2060
2800 37 61.6 2220
2920 37 57.3 2340
3080 36 53.7 2290
3200 36 51.4 2230
3360 36 49.8 2180
3520 36 48.6 2130
3680 36 47.1 2170
3760 36 47.1 2070
3920 36 49 2090
4000 37 49.8 2110
4120 37 50.2 2130
4280 38 51.4 2120
4400 38 52.5 2160
4520 39 53.7 2160
4640 39 54.5 2170
4720 39 54.9 2170
4840 39 55.3 2180
4960 40 55.7 2190
5080 41 56.1 2170
5160 42 56.5 2170
5280 42 56.5 2180
5400 43 57.3 2180
5480 43 57.3 2180
5600 44 57.6 2170
5680 45 58 2150
5760 45 57.6 2170
5840 45 56.9 2130
5960 45 56.1 2080
6040 45 55.3 2040Dbilas Intake in 4th gear:
Code:
'118
Engine Speed Intake Air Wastegate (N75) Boost Pressure
Temperature Duty Cycle (actual)
/min °C % mbar
1960 28 99.6 1250
2080 28 99.6 1350
2200 28 99.6 1470
2320 28 99.6 1590
2480 28 99.6 1760
2600 27 55.3 2000
2760 27 59.6 2270
2920 27 54.5 2380
3120 27 48.2 2270
3320 27 45.5 2120
3440 27 45.5 2060
3600 27 45.5 2070
3760 27 45.5 2070
3920 27 45.9 2050
4040 27 47.5 2070
4200 27 49 2090
4360 27 49.4 2120
4480 28 50.6 2140
4680 29 51.4 2130
4760 30 51.4 2130
4920 30 52.2 2120
5040 30 52.5 2140
5160 31 52.5 2130
5280 31 52.9 2120
5360 32 53.7 2120
5480 32 54.1 2120
5600 33 54.5 2120
5680 33 54.5 2120
5800 34 54.5 2090
5920 35 54.1 2060
6040 35 52.5 2010Obviously its not really a fair test as the logs were done on different days and the ambient temperatures were slightly warmer when i logged the stock intake. If i get time over the weekend i will try and get some better logs of both the stock and Dbilas intakes under the same conditions, but looking at the logs above there doesn't appear to be a great deal of difference between the two.
While i was out logging i thought i may aswell check my airflow readings and funnily enough they have since risen from 209g/s to 218g/s. I think next week i may knock up a little spacer for the maf tube to bring the maf more central and re-log it.
Dbilas airflow log in 3rd gear:
Code:
'003
Engine Speed Intake Air Mass Throttle Drive Ignition
Angle Sensor 1 Timing Angle
/min g/s % °ATDC
1800 33.36 99.6 16.5
1960 38.56 99.6 15.8
2120 44.08 99.6 16.5
2320 56.67 99.6 12.8
2520 65.08 99.6 11.3
2760 85.58 99.6 6.8
3080 116.14 99.6 0
3360 135.11 99.6 -2.3
3680 130.11 99.6 6.8
3960 138.06 99.6 10.5
4240 147.03 99.2 12
4560 161.14 99.6 8.3
4840 170.56 99.6 10.5
5080 184.69 99.6 11.3
5360 189.75 99.6 10.5
5680 207.94 99.6 9.8
5920 211.97 99.6 11.3
6200 215.86 99.6 13.5
6400 218.17 99.6 15
6600 218.69 99.6 16.5I've also noticed that since fitting the Dbilas intake my engine load values have gone to pot. Actual is no longer meeting the specified load whereas before fitting the intake it followed nicely. I assume this is down to false readings from the MAF sensor?
Similar threads
