BLow-off valve for TII
#1
Senior Member
Thread Starter
Join Date: Feb 2010
Location: Norway
Posts: 504
Likes: 0
Received 0 Likes
on
0 Posts
BLow-off valve for TII
I have asked this before, but how is it with open blow-off valves? Like, I have heard because of the mechanical AFM, the car doesn't like open blow-offs, but there is also something with single or dual pistoned valves, and so on.
Anyone know anything about this?
Anyone know anything about this?
#2
Hide the pinball machine
iTrader: (2)
Join Date: Aug 2007
Location: Sammamish, wa
Posts: 461
Likes: 0
Received 0 Likes
on
0 Posts
With the AFM, a BOV that vents to atmosphere is not really a great idea, because the ECU has already calculated how much air should be going into the engine, so when the BOV vents, it's not getting the air it thinks it is, and goes really rich. The way that this is overcome is to recirculate the BOV so it vents in back into the air stream at the turbo inlet duct.
I have no idea what single vs dual pistoned valves have anything to do with this, unless I completely missed the mark as to what you are talking about.
Also, a quick search could have told you all this.
I have no idea what single vs dual pistoned valves have anything to do with this, unless I completely missed the mark as to what you are talking about.
Also, a quick search could have told you all this.
#4
You get FIRE out the exhaust between shifts and revs with an open bov... which I love. Yeah the AFM goes rich for a second and if the exhaust is hot enough it ignites the fuel and shoots a flame... want videos? Doesn't bother me any. I run an old school HKS RS BOV (cause they just don't make them like they used to, huge, high flow and reliable), It doesn't "chirp" "tweet", "whistle" or make any other bird sounds or anything else like say an STI, just "woosh" and the psi is 0 within a second, like a bov should be.
#5
Rotary Enthusiast
I dont have mine recirculated either and no issues. Mine really doesnt shoot out a flame that often but when it decides to it deffinatley keeps people from tailgating
Trending Topics
#8
Senior Member
Thread Starter
Join Date: Feb 2010
Location: Norway
Posts: 504
Likes: 0
Received 0 Likes
on
0 Posts
So no problem except making Al Gore angry?`Well, the open ones are like 20$ cheaper here in Norway, ++.
I had a HKS SSQV on my Passat, open. The noise was so loud (I took out the part of the valve which made the noise really high), so I got a friend to make a resirc nipple instead. Just the same amount of noise, so didn't help, but the car became more responsive. Of course, a 97 Passat dont use mechanical AFMs, but rather proper electronical MAFs.
The point was the Passat was not recommended to run open with either, but it worked fine, except the little delay I got between gears because of the lost air.
I had a HKS SSQV on my Passat, open. The noise was so loud (I took out the part of the valve which made the noise really high), so I got a friend to make a resirc nipple instead. Just the same amount of noise, so didn't help, but the car became more responsive. Of course, a 97 Passat dont use mechanical AFMs, but rather proper electronical MAFs.
The point was the Passat was not recommended to run open with either, but it worked fine, except the little delay I got between gears because of the lost air.
#9
Engine, Not Motor
iTrader: (1)
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,789
Likes: 0
Received 108 Likes
on
91 Posts
On the other side, the RX-7 ECU runs so rich by default that it really isn't a big deal. And most FCs are running so poorly at this point on the stock ECU that any lag caused by an open vented BOV is probably not noticeable due to the bad TPS, clogged injectors, etc.
The long and short of it is that open venting a BOV works fine on the FC.
#10
Senior Member
Thread Starter
Join Date: Feb 2010
Location: Norway
Posts: 504
Likes: 0
Received 0 Likes
on
0 Posts
If you use an open valve the air that the turbo got in is pushed out again, and it got to suck new air in. But with a recirc the air is just vented into the turbo again, so you get a little bit more air straight after the gearshift. It is barely noticable, but it is there.
#13
Former FC enthusiast
iTrader: (2)
People that mention that crap are normally smart asses who want to make a point. I remember my Super Street teacher said some BS like "on cars with vane AFMs the engine will stall after a shift with an atmospheric dump BOV" lol...
In reality you probably won't even be able to notice a difference. I'm with arghx and others on this subject, and believe BOV's are a complete waste of money. No BOV ftw.
In reality you probably won't even be able to notice a difference. I'm with arghx and others on this subject, and believe BOV's are a complete waste of money. No BOV ftw.
#16
rotorhead
iTrader: (3)
I haven't had a functioning blowoff valve in years: https://www.rx7club.com/single-turbo-rx-7s-23/8-months-counting-no-blowoff-valve-884695/ but I have a standalone. I didn't really notice any difference besides the fluttering sound. Turbo hasn't blown up (it is an aftermarket Garrett).
Thread
Thread Starter
Forum
Replies
Last Post
Nosferatu
2nd Generation Specific (1986-1992)
7
09-05-15 02:13 PM