I recently took the car out with the vag-com attached and got some very interesting data back in a spreadsheet. I'll be happy to upload it if anyone cares enough to look at it.

I'm just wondering if itis reliable and accurate? If the boost aspect of it is right then I boost peaked at 27psi on one of my runs!!!Measured 1910mbar ot be exact.Sounds crazy I know. Sounds like a faulty n75 maybe?

Input is appreciated!!

 

yes the boost and timing measures are very accurate up till 22psi, above that its just guessing. We should of got a full 2bar map and not one that that only reaches 22psi [:@]

 

Audi measures boost with atmospheric pressure included, if you look at their spec sheets they say stuff like a 180's stock boost is 1.8 bar (26psi)...a stock 180 boosts just over 11psi.

A stock 225 boosts 14psi=.9 bar. Add 1 bar for the atmosphere and it comes out to 1.9bar, which is your reading.

 

Funny you should mention that... I was just looking at the data myself from the latest run I did and it said I boosted at 30psi?! So I was like, this can't be right, but then I remember my physics class way back when and realized that the sensor is also measuring ambient air pressure ~(14.5psi) while measuring the boost. Like you said, subtract ambient air and you get actual boost. Something I have noticed though is that my requested vs actual is off quite a bit but sometimes it spikes over requested. I don't know whether to believe I have a boost leak or a bad controller controlling the turbo. Here are some of the figures measuring block 115 on vag-com... me going through first and second gear at wot.

First column is time
Second is rpm
Third is requested boost
Fourth is actual boost


20.3910001190990
20.79200014101000
21.09204014201040
21.39180017601100
21.69140015101140
21.99140014801130
22.29152015501130
22.59172016401140
22.89188017501160
23.19204019301180
23.49228020001220
23.89260019901300
24.18284019601390
24.48312019401540
24.78344019301780
25.09384019301890
25.49428019201810
25.79460019401790
26.09496019901800
26.39528020501820
26.69556020901880
26.9957209802060
27.2952409801450
27.59412020201130
27.89408020401440
28.19420020501910
28.49436020502120
28.79452020401970
29.09464020401920
29.39480020401940
29.69492020401930
29.99508020601930
30.39524020501950
30.69540020601950
30.99552020701960
31.2954009801760
31.5949209801290
31.8944809801160
32.1840809801100
32.4837209801070
32.7833209801050
33.0829609801050
33.3826009801040
33.6822409801030
33.9818809801030

 

does the vag-com enable the used to change certain parameters in the car for added performance? or is this mainly a diag tool and reset tool?
thanks.

 

you can use vag to use lemminwinks to change some minor parameters to help fine tune your tune.

 

You can see when I change gear in the middle of the graph the lag for the boost. It looks like it's about 3/4 of a second. Is that normal?