View Full Version : Vag-Com Group 115 Boost - what's the highest it should read?
Aronis
May 5th, 2011, 03:08
I was logging blocks 2, 33 and 115 (looking for reason for 'air leaking noise') and need to know what the max boost number should be.
The log shows the Specified Boost and the Actual Boost.
The high I recorded at about 6080 rpm was a boost of 1690
RPM engine Boost Boost
------ load spec actual
2560 59.4 1670 940
4600 98.5 1640 1220
5440 149.6 1650 1610
6400 136.1 1700 1620
4880 154.9 1620 1640
5000 143.6 1600 1520
5400 146.6 1650 1600
5880 141.4 1670 1610
6280 139.8 1680 1650
6080 142.9 1650 1690
4480 16.5 980 1400
4360 12.8 980 1100
As I accelerated the specified boost lead the actual briefly (first date point).
Any thoughts?
Also I have a delta between bank one and bank two at the MAF sensor readings. The delta is typically about 20 % (each why, sometimes bank one higher sometimes bank two higher) with max deltas of about 60 percent with bank two being higher for those higher differences.
Mike
JSRS6
May 5th, 2011, 03:17
I assume you are stock, right Mike? If you look at any graph log of specified vs. actual boost, you will see specified rise before actual. That's turbo lag. If you are stock, your numbers are fine. As far as the lambdas go, they should be close to each other once you are in I believe closed loop?
JSRS6
May 5th, 2011, 03:19
Can you describe the "air leaking noise" in more detail?
4everRS
May 5th, 2011, 04:20
If not in closed loop, maf readings will be all over the place. In closed, 20% difference is way off base. These numbers are what a stock rs6 runs. Most off the shelf tunes will run 2000-2300 mbar on the high end.
Aronis
May 5th, 2011, 04:31
Stock.
Noise is heard with windows open when the RPM hits above 3500 or so. Sounds like air leaking out somewhere. My mechanic said it could be a stuck diverter valve.
The delta in MAF readings is a bit concerning.
No smoke, no odor. Intercooler surfaces are clean. No loose pipes on intercoolers. I looked when I did an oil change two weeks ago.
No real change in performance that stikes me as significant.
Mike
ben916
May 5th, 2011, 04:45
Stock.
Noise is heard with windows open when the RPM hits above 3500 or so. Sounds like air leaking out somewhere. My mechanic said it could be a stuck diverter valve.
The delta in MAF readings is a bit concerning.
No smoke, no odor. Intercooler surfaces are clean. No loose pipes on intercoolers. I looked when I did an oil change two weeks ago.
No real change in performance that stikes me as significant.
Mike
I would think a diverter valve
or.....
what would a stuck wastegate sound like?
Aronis
May 5th, 2011, 04:57
Any idea if a readable code could help determine the item?
JSRS6
May 5th, 2011, 05:09
You won't get a code for dv's or wg's, just for the solenoids controlling them.
JSRS6
May 5th, 2011, 05:11
If a wastegate was stuck open, you'd hear it in the exhaust. And you wouldn't be building those boost values.
JSRS6
May 5th, 2011, 05:16
Did you check ALL your hoses? I just recently had a hose come loose on my driver side lower hot side coming off the intermediate pipe. Didnt here the whoosh all the time, only when I got on it. That's where I would start. Don't just check them. Take them all off and clean them. Then go with t-bolt clamps. Could also be a very small crack or separation in a hose, that only makes it's presence known under full boost.
hahnmgh63
May 5th, 2011, 06:08
Max Boost seems about normal for a stock RS6 but it is coming a little late in the RPM range which could indicate a small leak. The small leak would lead to the Turbos taking longer to build full boost by having to spin faster. Have you checked your hoses & intercoolers for leaks? The air leaking noise sounds like a loose hose but they can sometimes be difficult to find but the intercooler hoses are the usual suspects. Remember you are looking for a leak downstream of the Turbos. Diverter valves as mentioned could be a possibility and fairly cheap to change if it has been a while. Diverter valves (710P) are $47 from Genuine but an Amazon search came up with $36.
http://www.amazon.com/Overrun-06A145710P-058145710A-Volkswagen-Passat/dp/B002SDRLLI
justin1230smith
May 5th, 2011, 15:19
I just had my 95,000 car serviced and both intercoolers had hairline cracks that were leaking - I had not noticed it in the performance as the turbos just had to work harder to maintain the pressure but since they have been replaced the boost climbs quicker resulting is less lag on a hard overtake - There were no trouble codes showing this though so would not have found it until the leak became bigger than the boost could cope with or until the turbos gave up ?
hahnmgh63
May 5th, 2011, 15:40
And as you can imagine, the overspeeding the Turbo's will shorten their life as they are sized to the car for a reason and just by chipping them we are overspeeding them somewhat depending on the wastegate's limit's too.
SzymekCRX
October 11th, 2011, 19:04
Still leaking ? You should do group 02 VAGCOM read to ensure both MAFs are reading quite similar values.
You can do a static leak test as well :) (like I'm doing now)
speedtrapped
October 11th, 2011, 19:47
curious....did u plug the turbo inlets? and the plug the DV's and presssurize thru one side of DV? I ask because I smoked my engine in past, but we did not seal off anything...
SzymekCRX
October 11th, 2011, 19:51
curious....did u plug the turbo inlets? and the plug the DV's and presssurize thru one side of DV? I ask because I smoked my engine in past, but we did not seal off anything...
Exactly ! Turbo inlets are 'clogged' and I am pressurizing intake manifold - found blown valve gasket this way, which is being replaced by me now :)