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Title: vent to atmosphere blow-off valve... yes really Post by: elRey on February 23, 2013, 08:14:08 PM vent to atmosphere blow-off valve
Only operating conditions I see being an issue is idle and cruise when vacuum in manifold hold valve open. Not interested in the why not's. Just interested in affected functions/maps that need to be considered. ps.This is the 'post a question before looking for myself', lazy thread. Ill dive into soon enough. just want a heads up first. Thanks, Rey Title: Re: vent to atmosphere blow-off valve... yes really Post by: ddillenger on February 23, 2013, 08:16:25 PM How about when you let off the throttle after a WOT run? The ecu thinks all that air is going into the engine, but it's lost out your blow off valve. I'd think you'd go super rich.
Title: Re: vent to atmosphere blow-off valve... yes really Post by: nyet on February 23, 2013, 09:56:13 PM There is no map you can tweak to fix it. Run blow through MAF or don't bother.
Title: Re: vent to atmosphere blow-off valve... yes really Post by: corradovolksb on February 23, 2013, 10:02:08 PM Ya the me7 MAF has to see the air flow back over it or the AFR will shoot rich between shift and cause performance issues. If you can deactivate this feature it would be possible to run a BOV. It's been a big debate for a long time weather or not to run a BOV on VAG cars so you might be opening a can of worms just my 2 cents.
Title: Re: vent to atmosphere blow-off valve... yes really Post by: fredrik_a on February 24, 2013, 01:07:07 AM I'd think you'd go super rich. Yes, it will run super rich, so rich that the spark plug can not ignite it and the fuel will end up in for instance the cat and start to burn there, running the risk of eventually destroying the cat. Title: Re: vent to atmosphere blow-off valve... yes really Post by: jibberjive on February 24, 2013, 04:15:00 AM Is it for a B5 S4? I may have an interesting blow-through MAF/blow-off valve solution for the 2.7t pretty soon. I'll mention it here later if/when it comes to fruition, but just thought I'd throw that out there.
Title: Re: vent to atmosphere blow-off valve... yes really Post by: elRey on February 24, 2013, 07:11:48 AM show me logs that have actual lambda meeting spec lambda between shifts instead of just dump fuel to go rich in the short period of time between shifts.
Looks like for that condition I should start with ESWE,ESUK,and ESUKA Title: Re: vent to atmosphere blow-off valve... yes really Post by: Bische on February 24, 2013, 08:23:03 PM CWBGMSZS = 1 ? :)
Title: Re: vent to atmosphere blow-off valve... yes really Post by: catbed on February 25, 2013, 03:01:44 PM I recall seeing in another thread that SnowTrooper said rich between shifts can be tuned out. Maybe he would like to chime in?
EDIT: from this thread http://nefariousmotorsports.com/forum/index.php?topic=531.45 (http://nefariousmotorsports.com/forum/index.php?topic=531.45) Mantis, run a maf, pre or post turbo doesnt really matter much because even the rich condition on shifts can be tuned out with the pre turbo setup and a bov, if you are running re-circ then all the better/easier for you. I am ordering the pro-m 3" tube soon. look into it, the price is right. it is intended for blow through and i really suggest you go this route if your plumbing is setup to allow it. both turbo and bov must be before the maf for the blow through to work right. Title: Re: vent to atmosphere blow-off valve... yes really Post by: elRey on February 25, 2013, 03:39:35 PM So that's moving MAF after BOV so the lost air doesn't matter. I'd like to explore BOV + stock MAF and MAF placement.
Thanks, Rey Title: Re: vent to atmosphere blow-off valve... yes really Post by: catbed on February 25, 2013, 04:55:36 PM So that's moving MAF after BOV so the lost air doesn't matter. I'd like to explore BOV + stock MAF and MAF placement. Thanks, Rey Read what he wrote again: even the rich condition on shifts can be tuned out with the pre turbo(MAF) setup and a bov Title: Re: vent to atmosphere blow-off valve... yes really Post by: elRey on February 25, 2013, 04:59:03 PM Ah. I missed that. Did I say this thread was because I'm lazy ;). You even bolded it for me.
Thanks! Title: Re: vent to atmosphere blow-off valve... yes really Post by: catbed on February 25, 2013, 05:04:27 PM No problem. I'm eagerly awaiting any input on this thread.
Title: Re: vent to atmosphere blow-off valve... yes really Post by: britishturbo on February 25, 2013, 10:10:59 PM I didn't try stock MAF + BOV but Blow Thru MAF + BOV works great for me.
Title: Re: vent to atmosphere blow-off valve... yes really Post by: Snow Trooper on February 27, 2013, 02:08:07 PM I need to look at old files as that was last year but iirc one of the best things to do was adjust kfkhfm (? On my phone) at the rpm and load points that correspond to your shifting/driving style. I had it dump the maf value just like the bov dumped air. The injector on time also dumps and the AFR read at the wideband stays more consistent. There was other stuff. Read the FR sections about evap air mass return calculations, n249 timing, maf back flow and so on. Sorry I'm not more help right now.
Title: Re: vent to atmosphere blow-off valve... yes really Post by: shane0569 on February 27, 2013, 02:34:20 PM I've been running DV/BOV combos for some time now and haven't noticed any performance issues following shifts...it only lets a tiny fraction of the air out...recommend those.
Title: Re: vent to atmosphere blow-off valve... yes really Post by: elRey on February 27, 2013, 02:42:39 PM main benefit I'm looking for is simplified fabrication of intake and charge piping. So, a DV/BOV won't help me there. Thanks for the input tho.
Title: Re: vent to atmosphere blow-off valve... yes really Post by: Gonzo on February 27, 2013, 11:39:28 PM Might as well do MAFless if you haven't yet.
Title: Re: vent to atmosphere blow-off valve... yes really Post by: Snow Trooper on February 28, 2013, 11:36:13 AM with the new 5120 hack and a proper map sensor you will see a lot of people going mafless.
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