highroad

Did some data logging this morning. The actual boost seem to be lower than the specified boost by quite a bit. It shows the most in second gear, but aslo shows up in the third gear roll on throttle. It almost seems that the boost stays constantly low between 3400 and 4400 rpm. Is this normal or should I be looking for a leak. I have a homemade leak tester leftover from my 92 S4 but I am not too sure how much pressure I should run while testing and if there are any hoses I should plug while testing. Here are some pics of the logs.

Second and Third gear:

<img src="http://pictureposter.audiworld.com/125663/23rd_gear.jpg">

Third gear
<img src="http://pictureposter.audiworld.com/125663/3rd_gear.jpg">

Thanks

Jack

quickaudi:STFA

do you have any codes?

highroad

Giac Flash on a 6 sp allroad

Fats:4.31 sec
Caps:4.92

No codes

quickaudi:STFA

and what MAF do you have - Bosch or Valeo?

highroad

Here is a log. The timing looks a bit funny. It drops at the area that is lagging behind on the boost. What do you think?


Engine Speed Mass Air Flow Throttle Valve Angle Ignition Timing Angle

2560 32.64 12.9 14.3
2640 50.33 21.2 26.3
2720 77.67 42.7 16.5
2800 101.25 83.5 18
2960 134.25 85.5 8.3
3120 167.31 87.8 11.3
3320 164.19 90.2 12.8
3480 176.75 93.3 12
3680 190.36 96.1 12.8
3920 200.44 98.8 9
4080 204.14 100 9
4320 213.17 100 9.8
4520 229.47 100 9
4720 242.81 100 9
4920 248.42 100 10.5
5160 248.42 100 12.8
5320 252.89 100 14.3
5520 255.44 100 14.3
5680 259.83 100 15
5880 260.58 100 15
6080 260.69 100 14.3
6240 260.22 100 15.8
263.14 100 15.8
260.97 100 19.5

quickaudi:STFA

check the accordian hose to make sure the vacuum line that plugs in it is still there and that you don't have any other intake leaks

replaced your air filter lately?