VAGCOM overboost question 2601mbar max??

[skyegtb]

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 %.

		Mass Air Flow	Atmospheric	Accel. Pedal Pos.	Engine Speed	Boost Pressure	Boost Pressure	Charge Pressure
	TIME	(actual)	Pressure	Sensor 1 (G79)	(G28)	(specified)	(actual)	Control Duty Cycle
Gear	STAMP	mg/str	mbar	%	/min	mbar	mbar	%
Change	8.65	255	989.4	0	2100	1030.2	1458.6	70.9
2nd	8.98	215	989.4	29.8	1701	1030.2	1295.4	70.5
2nd	9.3	520	989.4	77.3	1323	1356.6	1193.4	76.1
2nd	9.63	665	989.4	100	1512	2029.8	1193.4	76.1
2nd	9.95	770	989.4	100	1659	2193	1366.8	76.1
2nd	10.28	920	989.4	100	1848	2315.4	1611.6	71.3
2nd	10.6	1095	989.4	100	2079	2335.8	1948.2	47.4
2nd	10.94	1240	989.4	100	2331	2335.8	2376.6	34.3
2nd	11.28	1275	989.4	100	2604	2325.6	2601	12
2nd	11.59	1260	989.4	100	2877	2295	2601	4.8
2nd	11.92	1205	989.4	100	3108	2264.4	2601	4.8
2nd	12.22	1145	989.4	100	3339	2233.8	2601	4.8
2nd	12.54	1080	989.4	100	3549	2193	2601	4.8
2nd	12.84	1030	989.4	100	3759	2152.2	2601	4.8
2nd	13.16	985	989.4	100	3927	2091	2601	4.8
2nd	13.46	950	989.4	100	4116	1999.2	2601	4.8
2nd	13.78	905	989.4	100	4284	1907.4	2601	4.8
Change	14.08	920	989.4	0	4410	1836	2601	4.8

[JSRS6]

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]

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]

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 valvehis map sensor was faulty and showed a reading of 2900mb all the time.