but, since i think something got lost in the translation, here is a re-hash:
with bcs, holding it floored on tip car, boost drops to 6 psi at 5000 rpm, shift occurs, boost does not come back. release the reapply gas, boost comes back untill 5000 rpm, drops to 6 psi, repeat.....etc. etc.
also, shift before 5000 rpm when floored = no boost drop.
issue #2 why 6 psi, and not say 10-12 psi?
ecu sees knock at 4500+ rpm when set to max, closes DBW THROTTLE PLATE by 70%to reduce flow/boost pressure in manifold, will not come out of this mode until gas pedal is released and re-applied. closing the plate results in stock-level MAF readings....so the knock goes away.
why? newer passat turbo (like an AWW for this transverse dominated crowd) flows a bit more than the bcs was designed for...so turn it down a bit and the knock goes away (still able to achive nearly 1 bar across the band)....keep 11-12 psi to redline like a chip, no throttle plate closing.
plus, the usual jokers providing no useful information....
does that make more sense?
this was reported by 2001GTI as well, I thought he was able to fix it by cutting the config wire....maybe not?
I see it on my car now too...suspect poop oxygenated gas.
that's because the unit was designed around your car, if i'm reading his analysis correctly. i think it's because of the new turbos that when cranked up, the bcs overloads the car's program (because it is still using the stock program), and thus the throttle plate steps in and says "uhh....no." and retards the system. when you manually turn it down on the aww and newer engines, it doesn't make the car overreact as much and work against you.
very cool info, scott. i can't wait till i get mine so i can try these tests on my own. perhaps i should see if they are working on a new model for the k03 sport, though. (i know they were trying to get some vortexers with the newer engines to do some tests with.)
Edit: Note to self, don't start a reply before you leave work and post it the next day...lol
Yep, that kinda what I'm thinking. I think they've attempted to handle this issue with the config wire...my theory on what that wire does is always changing...guessing now that it does something to limit max wastegate control duty cycle when not cut, just don't think its quite right for all situations.
I added a plot showing the MAF drop-off when the throttle plate is closed by the ecu... http://members6.clubphoto.com/scott481496/534962/guest.phtml
Scotty, many thanks on finding this out. It does seem to explain the behavior of my car to the T. I have turned down the boost to 10 clicks from MAX and it's working much better. Even though the boost gauge reads only 10psi, it feels significantly quicker than that, so perhaps the BCS boost gauge may not be accurate.
I tried my "uphill test in 3rd" last night, set the bcs to max -7 clicks.
didn't have any power drop (except what would be expected due to turbo limitations), but let off at about 5500 rpm due to traffic (high enough anyway I guess). I think boost peaked somewhere above 13 psi but not 14.5, rolled off to somewhere between 11.5 and 13 but not as high as 13 (best I can tell from the bcs's gauge)....didn't have the VAG-COM hooked up, but I might do it tonight if its not raining.
You have an AWW, right? Did you cut the wire or leave it intact? Can you get 93 or 94 octane in your area? Try to log with the VAG if you can. I've seem the 11.5 indicator light up and hold at max-9, so you are probably at like 11 psi or something.
Hopefully I can find some block 2 data from a chipped AWW or AUG Passat for some more comparisons...
after talking with a few other users, seems that the knock "correction" values I'm seeing when set to max aren't out of the ordinary....ie the level of knock is "normal".
so maybe something else must be directing the ECU to close the throttle plate.
more to come.....
I haven't cut the blue wire as I've got an AWW. Unfortunately I don't have Vag-Com either so It's only through the G-Tech that I can figure out how much acceleration I'm getting in the test gear (usually 2nd gear). My boost dump seems more irratic then your 5000rpm knock sensor dump, so perhaps there is something else mechanically wrong with my setup. It sometimes dump boost at as low as 3500rpm. I don't know where to get 93 octane gas in vegas either, so I can't test the car with better gas.
I'd stay away from the blue wire cut for now.
DV maybe? how many miles do you have now? I know you've been "boosting" for a while now.
Do you see the boost dispay on the BCS drop if you feel the power loss? When the throttle plate closed on me (for whatever reason), the BCS gauge was still reporting a steady 14 psi....because the sensor is on the intake side of the throttle body. the flow through the throttle plate was reduced however, so the actual pressure in the manifold was ~ 6psi if you correlate it with the MAF readings.
So, if the BCS is reporting erratic boost then it might be something else than what I'm seeing.
A code scan and some logs would be pretty useful, nobody in your area with a VAGCOM?
blocks 2, 3, 22, 23, 115 would be useful to check.
The VAGCOM is great tool to have, especially if you'll be into VW/Audi for a while.
You can get the sharware software for free, and I've seen the connectors around for ~$70, this would allow you to check/clear codes, and view blocks up to 25. You can the purchase the full software at a later date for $99. Just a thought.
I'm no longer convinced that I had a knock problem (knock correction was low, and my A/F estimates seem to more than rich enough), so I've got to do some more poking around. Someone suggested checking EGT, I might try that next.
Yeah, I don't intend to cut the blue wire.
As for the boost, the BCS reads full boost when I crank it all the way up even when the boost is being dumped. Hence the boost reading is wrong and thus the boost dump must occur somewhere between the boost sensor and the engine.
Vag-Com seems like a nice tool, but I don't think I'm technical enough to tinker with gadgets like that, especially since I also don't have a laptop to log the data to when driving.
Also, the DV is recent as I upgraded the old one to the 2002 "N" verson in hope that it was the problem. It wasn't.
Anyways, it seems like the problem may not be limited to BCS modified cars. I've been reading on some other thread that seem to have the same symptoms as mine, but they are regarding chipped cars.
(don't know how to post links, but look for the title)
Car cutting out at about 3,300 RPM, Question.
Bad Wastegate? - Graph inside!!!
Oh well, I hope you have better luck isolating the problem and fixing it.
Hey Scotty, Yes, After i cut the blue wire my 5k problem was gone. The boost stayed the same and car did not feel any faster or slower. Cutting to blue wire just fixed my problem.
Some things i cant exsplain.
Hit the gas when the car was cool. Boost just droped at any given RPM, Let off the gas hit it again and the boost would just drop. After the car warmed up it was fine. no 5k drop off, just ran fine.
Weather started to get cooler:
Car still had the warm up problem of hitting the gas and boost would drop at any given RPM.
But this time i would get the 5k drop off problem every time i hit 5k no matter how warmed up my car was.
I was left with cutting the blue wire. Every thing was fine after that. I figured what did i have to lose. If the problem did not go away i was going to have Andy put in an UP chip. Turned out for the best in the end.
hmm, might be worth a try. i just wish i knew exactly what the wire was supposed to do.
i should probably email split-sec, although i'm not sure what it will get me.
been following the "bad wstegate " thread, have to check out the other. been toying around with putting the upgraded bosch DV in too...$35. mine makes a funny sound when at part throttle between 2500-3000 rpm, has pretty much done it since about 1k miles, so if figured it was normal.
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