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AARDQ
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« on: September 21, 2016, 08:13:25 AM »
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Hi, RS6 running 558 (no suffix). Not a lot of data points out there, so flying a bit blind as to what 'normal' should look like.
In the attached, one can see that up over 5,000 rpm pressure maxes at 1530 mbar even though WG is close to max duty cycle-- is that all I can expect given the altitude (pus_w 800 mbar)? Or am I looking at a leak (or even a turbo performance problem? I've sealed the intercoolers (small-ish leaks), checked the crankcase ventilation non-returned valve, checked the diverters, and leak-checked the intake tract with nothing found. Any components (check valves etc.) that would not turn up with a typical leak check?
Second question, is there any way to reach the wastegate adjustment nuts without at least dropping the engine? Sure doesn't look like it to me.
Second question, I've understood from others that Bank 1 mass air flow can be expected to be lower than Bank 2 due to tract differences. Given that both banks match almost perfectly, am I looking at something up with Bank 2 (i.e, should it be higher)?
Third question, I have tried moving cam timing around as an experiment (since pressure falls on its face right after the switch) but none of the cam maps (using the 558B .xdf as a reference to find them in 558) make a bit of difference to cam switchover point. Are the FRs missing info with respect to the RS6 cam details?
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nubcake
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« Reply #1 on: September 21, 2016, 08:41:07 AM »
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Seal MAFs better to get a more consistent reading (unbolt them from the airbox, wrap the "turbo" side with electrical tape until they are nice and tight there, then put the airbox on top). Don't get concerned with the variation between banks for now. Or if you absolutely insist on it - swap MAFs from one side to the other, then observe. Either way - it appears that MAF readings are more or less correct, ps_w follows pvdk nicely.
You can reach wastegate adjustment nuts, but it's not easy as you have found out.
RS6 turbos are very much limited by the wastegate actuator spring, even if you go all out - they will still drop to ~0.9-1.0 bar of boost by redline. Beware, stock injectors will max out prior to that, though.
KFNWSE and KFNWWLE are the maps to adjust for cams. Won't make much difference anyways.
Oh, and you seem to have some ignition retard happening prior to the WOT run, you'd probably want to decrease your ZW(2) map in that area.
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AARDQ
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« Reply #2 on: September 21, 2016, 08:58:47 AM »
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Thanks for that, frustrating that several days worth of effort and no apparent major issues and 1530-ish mbar is all there is.
It's weird, I've already pulled a bunch of timing, bone stock I was getting 9 clicks of adjustment. Doesn't seem right, even on 91.
Yes, KFNWSE and KFNWWLE. I tried them both at no adjustment, and I'm still getting exactly the same adjustment, somewhere around 4,700 rpms. I used the 558B .xdf to find them in the 558 file; they sure look like the right maps. I think I need to read the file back out, maybe MPPS isn't writing those segments? I dunno, grasping... Based on my 2.7T I wasn't expecting much change, but now I want to know what's going on that a change to the file (which does require checksum correction, so I know Tunerpro is making the change) isn;t showing up as expected during operation.
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nubcake
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« Reply #3 on: September 21, 2016, 09:08:38 AM »
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Yes, KFNWSE and KFNWWLE. I tried them both at no adjustment, and I'm still getting exactly the same adjustment, somewhere around 4,700 rpms. I used the 558B .xdf to find them in the 558 file; they sure look like the right maps. 0x2A270 and 0x2A370 for the 366304 file. |
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AARDQ
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« Reply #4 on: September 21, 2016, 09:23:28 AM »
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Thank you, those are indeed what I have.
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littco
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« Reply #5 on: September 22, 2016, 05:00:42 AM »
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Thank you, those are indeed what I have.
Actuators are really the issue here. To be able to get upto around 1.3bat at redline you need a stronger set of actuators. I don't think adding preload to the ones you have is going to make much difference to be honest as it normally affects the opening pressure not the max pressure.. |
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prj
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« Reply #6 on: September 22, 2016, 05:36:53 AM »
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Actuators are really the issue here. To be able to get upto around 1.3bat at redline you need a stronger set of actuators. I don't think adding preload to the ones you have is going to make much difference It will make all the difference. @ OP, did you pressure test the car? Remove hoses from intercoolers and pressure test through the intercoolers, the IC's are fucked on 99% of these cars. |
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10101011
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« Reply #7 on: September 22, 2016, 11:21:36 AM »
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Just like PRJ said . ... all RS6 factory intercoolers leak a lot or split apart . The intercoolers are most likely your problem IMHO :-)
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Poor quality lingers long after the price is forgotten ....
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AARDQ
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« Reply #8 on: September 22, 2016, 12:35:33 PM »
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Just like PRJ said . ... all RS6 factory intercoolers leak a lot or split apart . The intercoolers are most likely your problem IMHO :-)
LOL, first thing I did, resealed them (JB weld). Holding fine now. Pressure tested the entire tract, checked the crankcase ventilation non-return, no material leakage, checked the DVs properly. So I'm left with the actuators as littco and prj say. I'm at an atmospheric pressure of 800 mbar, so what nubcake said about only holding 0.8 to 0.9 bar supports the 1530 mbar max I'm seeing. I figured out my KFNWSE map problem (had it switched with WWLE) and it holds 1,650 mbar to redline (with quite a bit of WG left) if the cams are left retarded (of course slightly reduced MAF and load) so again that seems to support the actuators as being the weak link (as opposed to a leak). Maybe I can work helper springs in there... |
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« Last Edit: September 22, 2016, 12:37:44 PM by AARDQ »
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prj
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« Reply #9 on: September 22, 2016, 01:12:51 PM »
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Btw on stock injectors you will run out of fuel before you need to adjust actuators.
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AARDQ
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« Reply #10 on: September 22, 2016, 01:35:36 PM »
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At this point I'd be happy getting back to sea-level power.
From looking at KRKTE in the 558F and 558 files it looks like the Plus used the same injectors? Given the trans capabilities (or lack thereof), I'm not planning to go any higher than a Plus level of tune, if that.
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