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looking into getting a set of blow off valves

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  #11  
Old 04-01-2008, 10:51 AM
Joeski's Avatar
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Default RE: looking into getting a set of blow off valves



Completely different senario for the 2.7T motor.

OOOO
 
  #12  
Old 04-01-2008, 11:00 AM
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Default RE: looking into getting a set of blow off valves

ORIGINAL: slee22

In other words, theturbo Audisusea closed loop systemwhere unused boost is recirculated through the system, therefore you can't use BOV's since it will screw up MAF timings and such. You'll want diverter valves instead...
Actually most turbo cars are like that, but ricers don't seem to care anyway.
 
  #13  
Old 04-01-2008, 11:02 AM
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Default RE: looking into getting a set of blow off valves

ORIGINAL: turbo kraut

at least on the a4's you can use a bov........ but it has to be closed at idel or your car will stutter and die....... alot of people are using the hybrid valve... it has the option to be 80/20, 50/50, or 20/80...... but i know people using straight bov's........ maybe that isn't the case on the a6, but i know it works for the a4
Still absolutely stupid - the car will run rich if you vent to atmosphere and you will get a CEL at some point. It's absolutely same for 1.8T, 2.7T or any other forced induction motor that measures the air before the valve.
 
  #14  
Old 04-01-2008, 11:18 AM
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Default RE: looking into getting a set of blow off valves

ORIGINAL: halik

ORIGINAL: turbo kraut

at least on the a4's you can use a bov........ but it has to be closed at idel or your car will stutter and die....... alot of people are using the hybrid valve... it has the option to be 80/20, 50/50, or 20/80...... but i know people using straight bov's........ maybe that isn't the case on the a6, but i know it works for the a4
Still absolutely stupid - the car will run rich if you vent to atmosphere and you will get a CEL at some point. It's absolutely same for 1.8T, 2.7T or any other forced induction motor that measures the air before the valve.

that is not correct in......... there are a ton of guys running them on the 1.8t's...... the ecu will re-learn that you are not dumping enough air into the system and correct it....... iirc that is what the map sensor does..... along with the maf.......... search and you will see........ or as cincytt...... i guess the diode mod won't work for a car either then right
 
  #15  
Old 04-01-2008, 12:04 PM
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Default RE: looking into getting a set of blow off valves

ORIGINAL: turbo kraut

ORIGINAL: halik

ORIGINAL: turbo kraut

at least on the a4's you can use a bov........ but it has to be closed at idel or your car will stutter and die....... alot of people are using the hybrid valve... it has the option to be 80/20, 50/50, or 20/80...... but i know people using straight bov's........ maybe that isn't the case on the a6, but i know it works for the a4
Still absolutely stupid - the car will run rich if you vent to atmosphere and you will get a CEL at some point. It's absolutely same for 1.8T, 2.7T or any other forced induction motor that measures the air before the valve.


that is not correct in......... there are a ton of guys running them on the 1.8t's...... the ecu will re-learn that you are not dumping enough air into the system and correct it....... iirc that is what the map sensor does..... along with the maf.......... search and you will see........ or as cincytt...... i guess the diode mod won't work for a car either then right
How exactly will it re-learn? If you're dumping to atmosphere, the signals that made it to the ECU suggest a boost leak. Maf reads x CFM of air, which should translate to x PSI of pressure in the intake. If the PSI is less, it looks like the air is disappearing and the ecu has to trim down the fuel. Odds are you'll end up with fuel trim error codes on newer/more sophisticated ecus. Definitely a stupid thing to have only because you want to live out your Paul Walker wet dreams...
 
  #16  
Old 04-01-2008, 12:42 PM
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Default RE: looking into getting a set of blow off valves

see, i think you think i am running a bov....... actually i am running a stratosphere dv


here this explains it........ like i said with the map sensor.... it relearns the setup

What kind of BOV should I get?

Due to the closed loop turbo system in our A4's you can not release the air into the atmosphere, you have to recirculate it back into the system. The MAF calculates air before the DV so if any air is lost after that calculation by releasing it into the atmosphere you will run rich for a little while. How damaging this is, is disputable, but on 2000+ models the car adapts to running a BOV because of the MAP sensor so you will only run rich for a day or 2. The BOV will need to stay closed at idle. A BOV that remains open at idle is not good for a car with a MAF and you will stutter and stall. Forge 004 and SSQV are both closed at idle and good choices. If you run standalone software (034 Motorsports carries it) you can run any BOV you want.

There are also hybrid BOV's that only vent a portion of the air. The most popular are the Forge Splitter, and GFB. The splitter is the easiest to install and run and the GFB is just a little tougher, but you can adjust the amount released to atmosphere for 10-50%. The GFB is ~$250 and the Forge is $175 and can only release 10% vta or full dv (should only be left as both since it releases more air).

And if you have a B6, they are equipped with a Wideband o2, stock. the ECU is programmed from the factory with the target AFR, and it will adjust fuel trims accordingly to maintain that, tuned or untuned. So you can remove your MAF and run any BOV you want. Won't work with b5's.

If you have a pre-00 A4 can you run a BOV? Technically no, but I run one on my 98.5 with no problems whatsoever. You only run slightly rich right after you "blow-off" and I can't see it doing any damage. Maybe a catalytic converter in the long run, but I doubt it.
 
  #17  
Old 04-01-2008, 12:49 PM
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Default RE: looking into getting a set of blow off valves

ORIGINAL: halik



Still absolutely stupid - the car will run rich if you vent to atmosphere and you will get a CEL at some point. It's absolutely same for 1.8T, 2.7T or any other forced induction motor that measures the air before the valve.



How exactly will it re-learn? If you're dumping to atmosphere, the signals that made it to the ECU suggest a boost leak. Maf reads x CFM of air, which should translate to x PSI of pressure in the intake. If the PSI is less, it looks like the air is disappearing and the ecu has to trim down the fuel. Odds are you'll end up with fuel trim error codes on newer/more sophisticated ecus. Definitely a stupid thing to have only because you want to live out your Paul Walker wet dreams...
this is the close mindedness i would expect over on audiworld........ not on af......... af used to be this way, probably because alot of guys here cam from there first, and listened to the rubish that spewed out of the mouths over there


i remeber one time, i got a K&N drop in filter and one guy on aw told me to sell my car cause it was going to die because i changed my air filter........ that is just plain insanity..... if it is oiled it will hurt your maf, but in no way kill your car completely.....same as a bov won't kill your car
 
  #18  
Old 04-01-2008, 01:04 PM
halik's Avatar
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Default RE: looking into getting a set of blow off valves

ORIGINAL: turbo kraut

see, i think you think i am running a bov....... actually i am running a stratosphere dv


here this explains it........ like i said with the map sensor.... it relearns the setup

What kind of BOV should I get?

Due to the closed loop turbo system in our A4's you can not release the air into the atmosphere, you have to recirculate it back into the system. The MAF calculates air before the DV so if any air is lost after that calculation by releasing it into the atmosphere you will run rich for a little while. How damaging this is, is disputable, but on 2000+ models the car adapts to running a BOV because of the MAP sensor so you will only run rich for a day or 2. The BOV will need to stay closed at idle. A BOV that remains open at idle is not good for a car with a MAF and you will stutter and stall. Forge 004 and SSQV are both closed at idle and good choices. If you run standalone software (034 Motorsports carries it) you can run any BOV you want.

There are also hybrid BOV's that only vent a portion of the air. The most popular are the Forge Splitter, and GFB. The splitter is the easiest to install and run and the GFB is just a little tougher, but you can adjust the amount released to atmosphere for 10-50%. The GFB is ~$250 and the Forge is $175 and can only release 10% vta or full dv (should only be left as both since it releases more air).

And if you have a B6, they are equipped with a Wideband o2, stock. the ECU is programmed from the factory with the target AFR, and it will adjust fuel trims accordingly to maintain that, tuned or untuned. So you can remove your MAF and run any BOV you want. Won't work with b5's.

If you have a pre-00 A4 can you run a BOV? Technically no, but I run one on my 98.5 with no problems whatsoever. You only run slightly rich right after you "blow-off" and I can't see it doing any damage. Maybe a catalytic converter in the long run, but I doubt it.
Wow i had no idea that b6 cars come with wideband o2 sensors... that's awesome. Do you have a reference for the 2000+ learning ECU thing? I can't think of a reason why the car would adjust to an error condition - boost leak is something you should CEL on.
 
  #19  
Old 04-01-2008, 01:06 PM
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Default RE: looking into getting a set of blow off valves

i have a 02 a6 2.7t and i just ordered the forge hybrids ... should i not put them on my car ?? or will it adapt ... you guys lost me in all the posts lol??
 
  #20  
Old 04-01-2008, 01:07 PM
halik's Avatar
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Default RE: looking into getting a set of blow off valves

ORIGINAL: turbo kraut

ORIGINAL: halik



Still absolutely stupid - the car will run rich if you vent to atmosphere and you will get a CEL at some point. It's absolutely same for 1.8T, 2.7T or any other forced induction motor that measures the air before the valve.



How exactly will it re-learn? If you're dumping to atmosphere, the signals that made it to the ECU suggest a boost leak. Maf reads x CFM of air, which should translate to x PSI of pressure in the intake. If the PSI is less, it looks like the air is disappearing and the ecu has to trim down the fuel. Odds are you'll end up with fuel trim error codes on newer/more sophisticated ecus. Definitely a stupid thing to have only because you want to live out your Paul Walker wet dreams...
this is the close mindedness i would expect over on audiworld........ not on af......... af used to be this way, probably because alot of guys here cam from there first, and listened to the rubish that spewed out of the mouths over there


i remeber one time, i got a K&N drop in filter and one guy on aw told me to sell my car cause it was going to die because i changed my air filter........ that is just plain insanity..... if it is oiled it will hurt your maf, but in no way kill your car completely.....same as a bov won't kill your car
I've never owned a 1.8t, but I've had several fast DSMs (my brother had a 450hp monster one also) and I've got a 2.7T currently. It's the same principle everywhere else - you're losing measured air. It won't kill the car, but running rich because the car will go "pfffffffffffffffffff" is stupid in my head.
 


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