venting bov into maf intake stream?

[marshmallow15]

i know for the b6t or bpt, you need to do this because otherwise, the ratio will be too rich, but do i need to do this for the b6e or can i vent into the atmosphere with a turbo xs bov like other setups?

[OsoSlo z28]

it's not the motor that causes the problem, it's the metering device. anything with a maf or vaf will have to have the bov/bypass valve recirced back into the intake pipe(after the metering device).

[marshmallow15]

after meaning between tb and maf/vaf, or between maf/vaf and intake?

[OsoSlo z28]

between the tb and maf because the air is already accounted for.

[Ryencool]

so wiht the engines do you still get teh woosh sound or no?

[jonathanj]

i have a hks blow off valve. its not venting back in to the system. and im having no problems. but cars are funny like that. i hang out with a bunch of dsm guys and some run open bov and have no probs, while others cant do it or there car wont even stay running. Ashley is also right about the air being acounted for. when i shift it does let out black smoke. (black smoke means rich).so try it and the worse that can happen is youd have to buy a rerouting tube for you bov

[OsoSlo z28]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Ryencool:<BR><STRONG>so wiht the engines do you still get teh woosh sound or no?</STRONG><HR></BLOCKQUOTE><P>you still get the sound but it is muffled by the return piping.

[Ryencool]

muffled as in cant hear it muffled? thats kind of upsetting..I want to swap and i want that damn noise lol..whats the problem with not rerouting it? why does the car die?<P><BR>I have maximum boost, but I cant find an explanation to this anywhere, ive hear od f it before jsut cant remember lol...<p>[ November 10, 2002: Message edited by: Ryencool ]

[cjthor]

cant the super afc compensate for the atmosphere bov?

[Ryencool]

exactly what I thought...what if your running a haltech or sfac?

[Ryencool]

exactly what I thought...what if your running a haltech or sfac?

[OsoSlo z28]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Ryencool:<BR><STRONG>exactly what I thought...what if your running a haltech or sfac?</STRONG><HR></BLOCKQUOTE><P>the s-afc is questionable, the haltech uses a map sensor.

[marshmallow15]

if you run a halteck, i dont think you'll need the maf. plus the sound of venting the air back into the tube is still pretty loud...sounds like a bypass valve *which is practically the same thing* and instead of a whoosh it sounds more like a hiss that starts with a 'kaaa'....well my friend's does.

[rikymaru]

Well, to make things short:<P>No, venting to the atmosphere is bad. REAL bad. Your ECU calculates the air/fuel mixture during intake (at the MAS actually) in most cars with a Mass Air Sensor. So if you are taking in 14 parts air then the car will give 1 part fuel like it is supposed to. I assume everyone in the topic knows how a BOV works so I'll skip that part. When you shift while racing I'm surey ou are in the 6000 RPM range. At the same time the BOV send the air back into the tract and the ECU isn't proven wrong. You keep a good fuel mixture and you still have the "noise" everyone wants; it's just not as loud as the drag cars you've come to know.<P>Now lets say we vent to the atmoshpere:<BR>When you shift at 6-7k RPMs the BOV is going to let out taht "neato" sound which is cool! At the same time you are going to smell fuel and see black smoke come out the back of you car. The hell happened?<P>When you dump to the atmosphere the ECU thinks that air that is being ejected from the intake track is actually being ingested into the motor and supplies a given amount of fuel to match the metered air. But that figure is now incorrect because the air is not going into the motor its going into the air, so now you have an incorrect air/fuel ratio between shifts. You just vented it all to the air for a cool sound and now you have it at the cost of performance. Doh!<BR> <BR>This topic is done to death on DSMs, Turbo FD/FCs, Supras, and etc. Venting hurts your car no matter how "good" you think your car is running. People do it and for some reason never see the clouds of smoke and smell the fuel. But the performance is still hurt.<P>An SAFC will not solve the problem either unless you have the air-to-fuel maps set on an exact shift you do everytime. Basically, you can set the SAFC to compensate with a good fuel mix at 7k RPMs but if you eer shift at 3-6k RPMSs you are still going to hurt your performance. <P>Soe BOV are made to vent. I know HKS makes one. They also make something called a VPC. Ahem:<P>VPC is designed to physically and electronically replace OE air metering devices which present a significant restriction to the intake system and offer no adjustment or reprogramming options to take advantage of dramatically higher air flow or larger fuel injectors. The VPC converts both air flow meter and air mass sensor systems to what is referred to as speed density systems by utilizing a 16 bit central processing unit reading its own intake air temperature sensor and absolute pressure transducer (B-MAP sensor) signals. This unique conversion feature not only allows the VPC to replace the factory air flow metering device, but also eliminates the need for a fuel cut defencer. Another benefit of the VPC is the ability to create our own programs to take advantage of larger fuel injectors and new air flow characteristics (larger turbos). In some specific instances, the VPC may be used in addition to the PFC F-Con and larger injectors for the ultimate in HKS plug-in fuel system technology. VPC equipped vehicles respond quicker with improved horsepower. <P>Yea, I got a summary from another site <P>Want to vent: Get the HKS VPC.

[marshmallow15]

man if only there was something that would switch the ratio to really lean when shifting and then back to the normal ratio so that we can vent into the atmosphere without worrying about burning too much fuel w/ less air when shifting.