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skyegtb
May 15th, 2011, 10:58
VAGCOM overboost question 2601mbar max??
Sorry for an off - RS6 post, but I feel this info is relevant to similar RS6 testing.
Recently did some diagnostics on my wifes 2005 VW Touran 2.0TDI to check out an overboost issue. Long story short the issue was seized vanes on the VNT (variable vane) turbo which I resolved by cleaning - this is an extremely common issue on VNT cars.
Anyway, I did some 'before and after' logging with VAGCOM to check out the problem and prior to fixing it I got the below log. This was a 2nd gear WOT log. As you can see the overboost began at 2604rpm until I changed to 3rd gear.
My question is this: Does VAGCOM max out at 2601mbar because it seems odd to me that a turbo that was basically spooling out of control would max out at a set figure across the rev band?

For info, since chemically cleaning the VNT the specified and actual boost were within a few %.


<table style="width: 574pt; border-collapse: collapse;" border="0" cellSpacing="0" cellPadding="0" width="764"> <colgroup><col style="width: 38pt; mso-width-source: userset; mso-width-alt: 1792;" width="50"> <col style="width: 36pt; mso-width-source: userset; mso-width-alt: 1706;" width="48"> <col style="width: 66pt; mso-width-source: userset; mso-width-alt: 3128;" width="88"> <col style="width: 61pt; mso-width-source: userset; mso-width-alt: 2872;" width="81"> <col style="width: 80pt; mso-width-source: userset; mso-width-alt: 3783;" width="106"> <col style="width: 63pt; mso-width-source: userset; mso-width-alt: 2986;" width="84"> <col style="width: 71pt; mso-width-source: userset; mso-width-alt: 3384;" span="2" width="95"> <col style="width: 88pt; mso-width-source: userset; mso-width-alt: 4152;" width="117"> <tbody><tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; width: 38pt; height: 14.4pt; background-color: transparent;" height="19" width="50"></td> <td style="border: 0px black; width: 36pt; background-color: transparent;" width="48"></td> <td style="border: 0px black; width: 66pt; background-color: transparent;" width="88">Mass Air Flow</td> <td style="border: 0px black; width: 61pt; background-color: transparent;" width="81">Atmospheric</td> <td style="border: 0px black; width: 80pt; background-color: transparent;" width="106">Accel. Pedal Pos.</td> <td style="border: 0px black; width: 63pt; background-color: transparent;" width="84">Engine Speed</td> <td style="border: 0px black; width: 71pt; background-color: transparent;" width="95">Boost Pressure</td> <td style="border: 0px black; width: 71pt; background-color: transparent;" width="95">Boost Pressure</td> <td style="border: 0px black; width: 88pt; background-color: transparent;" width="117">Charge Pressure</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19"></td> <td style="border: 0px black; background-color: transparent;">TIME</td> <td style="border: 0px black; background-color: transparent;">(actual)</td> <td style="border: 0px black; background-color: transparent;">Pressure</td> <td style="border: 0px black; background-color: transparent;">Sensor 1 (G79)</td> <td style="border: 0px black; background-color: transparent;">(G28)</td> <td style="border: 0px black; background-color: transparent;">(specified)</td> <td style="border: 0px black; background-color: transparent;">(actual)</td> <td style="border: 0px black; background-color: transparent;">Control Duty Cycle</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">Gear</td> <td style="border: 0px black; background-color: transparent;">STAMP</td> <td style="border: 0px black; background-color: transparent;"> mg/str</td> <td style="border: 0px black; background-color: transparent;"> mbar</td> <td style="border: 0px black; background-color: transparent;"> %</td> <td style="border: 0px black; background-color: transparent;"> /min</td> <td style="border: 0px black; background-color: transparent;"> mbar</td> <td style="border: 0px black; background-color: transparent;"> mbar</td> <td style="border: 0px black; background-color: transparent;"> %</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">Change</td> <td style="border: 0px black; background-color: transparent;" align="right">8.65</td> <td style="border: 0px black; background-color: transparent;" align="right">255</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">0</td> <td style="border: 0px black; background-color: transparent;" align="right">2100</td> <td style="border: 0px black; background-color: transparent;" align="right">1030.2</td> <td style="border: 0px black; background-color: transparent;" align="right">1458.6</td> <td style="border: 0px black; background-color: transparent;" align="right">70.9</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">8.98</td> <td style="border: 0px black; background-color: transparent;" align="right">215</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">29.8</td> <td style="border: 0px black; background-color: transparent;" align="right">1701</td> <td style="border: 0px black; background-color: transparent;" align="right">1030.2</td> <td style="border: 0px black; background-color: transparent;" align="right">1295.4</td> <td style="border: 0px black; background-color: transparent;" align="right">70.5</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">9.3</td> <td style="border: 0px black; background-color: transparent;" align="right">520</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">77.3</td> <td style="border: 0px black; background-color: transparent;" align="right">1323</td> <td style="border: 0px black; background-color: transparent;" align="right">1356.6</td> <td style="border: 0px black; background-color: transparent;" align="right">1193.4</td> <td style="border: 0px black; background-color: transparent;" align="right">76.1</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">9.63</td> <td style="border: 0px black; background-color: transparent;" align="right">665</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">100</td> <td style="border: 0px black; background-color: transparent;" align="right">1512</td> <td style="border: 0px black; background-color: transparent;" align="right">2029.8</td> <td style="border: 0px black; background-color: transparent;" align="right">1193.4</td> <td style="border: 0px black; background-color: transparent;" align="right">76.1</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">9.95</td> <td style="border: 0px black; background-color: transparent;" align="right">770</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">100</td> <td style="border: 0px black; background-color: transparent;" align="right">1659</td> <td style="border: 0px black; background-color: transparent;" align="right">2193</td> <td style="border: 0px black; background-color: transparent;" align="right">1366.8</td> <td style="border: 0px black; background-color: transparent;" align="right">76.1</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">10.28</td> <td style="border: 0px black; background-color: transparent;" align="right">920</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">100</td> <td style="border: 0px black; background-color: transparent;" align="right">1848</td> <td style="border: 0px black; background-color: transparent;" align="right">2315.4</td> <td style="border: 0px black; background-color: transparent;" align="right">1611.6</td> <td style="border: 0px black; background-color: transparent;" align="right">71.3</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">10.6</td> <td style="border: 0px black; background-color: transparent;" align="right">1095</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">100</td> <td style="border: 0px black; background-color: transparent;" align="right">2079</td> <td style="border: 0px black; background-color: transparent;" align="right">2335.8</td> <td style="border: 0px black; background-color: transparent;" align="right">1948.2</td> <td style="border: 0px black; background-color: transparent;" align="right">47.4</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">10.94</td> <td style="border: 0px black; background-color: transparent;" align="right">1240</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">100</td> <td style="border: 0px black; background-color: transparent;" align="right">2331</td> <td style="border: 0px black; background-color: transparent;" align="right">2335.8</td> <td style="border: 0px black; background-color: transparent;" align="right">2376.6</td> <td style="border: 0px black; background-color: transparent;" align="right">34.3</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">11.28</td> <td style="border: 0px black; background-color: transparent;" align="right">1275</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">100</td> <td style="border: 0px black; background-color: transparent;" align="right">2604</td> <td style="border: 0px black; background-color: transparent;" align="right">2325.6</td> <td style="border: 0px black; background-color: yellow;" class="xl63" align="right">2601</td> <td style="border: 0px black; background-color: transparent;" align="right">12</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">11.59</td> <td style="border: 0px black; background-color: transparent;" align="right">1260</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">100</td> <td style="border: 0px black; background-color: transparent;" align="right">2877</td> <td style="border: 0px black; background-color: transparent;" align="right">2295</td> <td style="border: 0px black; background-color: yellow;" class="xl63" align="right">2601</td> <td style="border: 0px black; background-color: transparent;" align="right">4.8</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">11.92</td> <td style="border: 0px black; background-color: transparent;" align="right">1205</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">100</td> <td style="border: 0px black; background-color: transparent;" align="right">3108</td> <td style="border: 0px black; background-color: transparent;" align="right">2264.4</td> <td style="border: 0px black; background-color: yellow;" class="xl63" align="right">2601</td> <td style="border: 0px black; background-color: transparent;" align="right">4.8</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">12.22</td> <td style="border: 0px black; background-color: transparent;" align="right">1145</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">100</td> <td style="border: 0px black; background-color: transparent;" align="right">3339</td> <td style="border: 0px black; background-color: transparent;" align="right">2233.8</td> <td style="border: 0px black; background-color: yellow;" class="xl63" align="right">2601</td> <td style="border: 0px black; background-color: transparent;" align="right">4.8</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">12.54</td> <td style="border: 0px black; background-color: transparent;" align="right">1080</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">100</td> <td style="border: 0px black; background-color: transparent;" align="right">3549</td> <td style="border: 0px black; background-color: transparent;" align="right">2193</td> <td style="border: 0px black; background-color: yellow;" class="xl63" align="right">2601</td> <td style="border: 0px black; background-color: transparent;" align="right">4.8</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">12.84</td> <td style="border: 0px black; background-color: transparent;" align="right">1030</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">100</td> <td style="border: 0px black; background-color: transparent;" align="right">3759</td> <td style="border: 0px black; background-color: transparent;" align="right">2152.2</td> <td style="border: 0px black; background-color: yellow;" class="xl63" align="right">2601</td> <td style="border: 0px black; background-color: transparent;" align="right">4.8</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">13.16</td> <td style="border: 0px black; background-color: transparent;" align="right">985</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">100</td> <td style="border: 0px black; background-color: transparent;" align="right">3927</td> <td style="border: 0px black; background-color: transparent;" align="right">2091</td> <td style="border: 0px black; background-color: yellow;" class="xl63" align="right">2601</td> <td style="border: 0px black; background-color: transparent;" align="right">4.8</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">13.46</td> <td style="border: 0px black; background-color: transparent;" align="right">950</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">100</td> <td style="border: 0px black; background-color: transparent;" align="right">4116</td> <td style="border: 0px black; background-color: transparent;" align="right">1999.2</td> <td style="border: 0px black; background-color: yellow;" class="xl63" align="right">2601</td> <td style="border: 0px black; background-color: transparent;" align="right">4.8</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">2nd</td> <td style="border: 0px black; background-color: transparent;" align="right">13.78</td> <td style="border: 0px black; background-color: transparent;" align="right">905</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">100</td> <td style="border: 0px black; background-color: transparent;" align="right">4284</td> <td style="border: 0px black; background-color: transparent;" align="right">1907.4</td> <td style="border: 0px black; background-color: yellow;" class="xl63" align="right">2601</td> <td style="border: 0px black; background-color: transparent;" align="right">4.8</td> </tr> <tr style="height: 14.4pt;" height="19"> <td style="border: 0px black; height: 14.4pt; background-color: transparent;" height="19">Change</td> <td style="border: 0px black; background-color: transparent;" align="right">14.08</td> <td style="border: 0px black; background-color: transparent;" align="right">920</td> <td style="border: 0px black; background-color: transparent;" align="right">989.4</td> <td style="border: 0px black; background-color: transparent;" align="right">0</td> <td style="border: 0px black; background-color: transparent;" align="right">4410</td> <td style="border: 0px black; background-color: transparent;" align="right">1836</td> <td style="border: 0px black; background-color: yellow;" class="xl63" align="right">2601</td> <td style="border: 0px black; background-color: transparent;" align="right">4.8</td> </tr></tbody></table>

JSRS6
May 15th, 2011, 15:23
I dont think that has anything to do with vcds, rather with with tolerances of the sensor in the car. Its the same way the mafs will max out at 364 or something like that.

skyegtb
May 15th, 2011, 16:17
I dont think that has anything to do with vcds, rather with with tolerances of the sensor in the car. Its the same way the mafs will max out at 364 or something like that.
Yep, I was kind of thinking that might be the issue there. I will need to log my RS6 when I get home for a comparison, had the car (and the VAGCOM) 4 years and yet to do any logging on the open road!!

bilko1
May 15th, 2011, 22:23
I logged a friends a4 1.9 tdi yesterday as he had the usual overboost then lack of power fault after a garage replaced turbo, maf and n75 valve:cry:his map sensor was faulty and showed a reading of 2900mb all the time.