BOV, to recirculate or to atmosphere?

[nocwage]

I've heard that since we've got an MAF a BOV can wreak havoc if we don't recirculate the air back into the intake..

Is this true?Since the CA powered cars didn't have one stock I'd like to add one to my silvia, but if I have to recirculate the air I'll need to cut a hole or something in my piping, I'd rather just blow to atmosphere..

Also position of the BOV? I heard it's better to have it close to the throttle body but i've seen a lot of people have it on their hotpipe. Was the hotpipe just cause it was easy to weld the flange on or is there a benefit to having it there?

[rico05]

You need to recuric it. Because the BOV comes after the MAF, the air is already metered that the BOV vents. This means that the MAF will think that "x" amount of air has passed through it, so it tells the ECU that "x" amount is comming into the engine for combustion. When you vent the BOV, air escapes (call ti value "y") that the ECU thinks is on its way to the combustion chamber. This air has already been dolled out the appropriate amount of fuel, and since it never reaches the combustion chamber, you will run very rich (ECU gives the fuel and igniton for "x", but in reality, you are actually putting "x-y" into the motor). My buddy went through about a set of plugs every 3-4 weeks vented! You have several options if you MUST vent:- Get a D-Jeitro computer (Apex Power FC w/ D-J software, SDS, Link, Motec etc standalone w/ MAP sensor)- Set up your MAF for blow through. To do this you must put the MAF inline on the coldpipe, but not too close to the throttle body, as combustion puleses can freak out the MAF-Get an HKS VPC (Vein Pressure COntroller) It is a little magic box that overrides the stock MAF and uses a propriatery MAP sensor and converts the signal from that to something the stock ECU can read.

I am going to weld up my own SMIC coldpipe and in the process, I am going to see what I can do w/ blow through. Here is a good discussion on the procedure for blow though:http://www.sr20forum.com/showthread.php?t=81442

The debate continues on the location. Because I am running low boost (soon to be lucky 13psi) I will jsut leave it on the hotpipe. Dee runs one on both the cold and hot pipe, but he is insane and runs gobs of boost (Dee is the MAN).

[nocwage]

So if I recirculate the air it should recirc back before the turbo and after the MAF correct?

[nab911]

My maf is right after the BOV but still a bit from the TB so mine is fine. If you recirc... blow the air into the intake pipe into the front of the turbo so it gives it a little air boost during shifts for good gear transition

[rico05]

Hey nab...would you shoot a pic of your setup PLEASE? Post it here or email it to:[email protected]

Thanks bro!

[nab911]

Yeah, i gotta get pics soon anyways. I just got it back from the shop and they just decided to make my maf blow through right after the BOV and weld all my intercooler piping for free... i love those guys

[USDM_OneVia]

I blow to the atmosphere and the car really doesn't freak out too much. Every now and then it will backfire/pop out of the exhaust, but it doesn't stumble or stall out.

I bought the HKS recirc kit when I bought my BOV fully intending on recircing it, but since it runs ok, I am just going to leave it as is.

Joe

[f s t caz]

I blow to the atmosphere and the car really doesn't freak out too much. Every now and then it will backfire/pop out of the exhaust, but it doesn't stumble or stall out.

what he said...

Quote »I bought the HKS recirc kit when I bought my BOV fully intending on recircing it, but since it runs ok, I am just going to leave it as is.

Joe [/quote]

how much did that cost? want to sell it? I'm tired of the sound and figure it's probably just safer and want to recirc it when i upgrade intercooler piping.

[iliketocrash]

i know quite a few people who vent to the atmosphere without a problem (including me). i checked my plaugs after reading this and they look fine to me. then again this seems to vary from car to car because i have heard lots of stories about such bad side effects caused by venting. one thing for sure though. if your car stalls for some reason while venting to the atmosphere then it usually has something to do with the bov. the bov should always remain completely shut at idle. if the bov leaks at idle then it'll cause your car to run like crap and sometimes stall, depending on the severity of the air leak.

[Rookie_ca18]

I have a fmic, greddy type S its on the hotpipe and vents with no problems.

[rico05]

i know quite a few people who vent to the atmosphere without a problem (including me).

I have heard of some people having issues, and others not. I guess it is just luck or unluck. All I know is, both my friends that vented had issues. Plus, you get back on boost faster if you recuric.

[Rookie_ca18]

I say go ahead and recirc the damn thing, this way if your car is running funny its one less thing to rule out. Do they make a recirc kit for the greddy type s (it has a pretty big opening).

[rico05]

Well, I am gonna try and run my ARC vented (as soon as it gets here:D)

[USDM_OneVia]

what he said...



how much did that cost? want to sell it? I'm tired of the sound and figure it's probably just safer and want to recirc it when i upgrade intercooler piping.

I paid 10 bucks for it, so 10 bucks and its yours. Brand new too.

Joe

[f s t caz]

I paid 10 bucks for it, so 10 bucks and its yours. Brand new too.

Joe

what all is included? pics? you take paypal? thanks

Chris

[Neejay]

You guys never get tired of the BOV sound? I know since Ive never driven a turbo car before, I'd enjoy the sound at first, but wouldnt it get tiring after a while?

Im highly debating on getting a automatic ca18 anyway, as Im super lazy, Ive never had a manual car, and I barely know how to drive one (I dont ever get practice, but I can). Im also under the impression that the BOV wouldnt be to loud anyway with an automatic.

[Rookie_ca18]

Dont wanna hear it stay off boost....yea, guess I could see your point.

[Neejay]

Dont wanna hear it stay off boost....yea, guess I could see your point.

hmm??

And whats so bad about automatic turbo anyway? Wouldnt it mean you could build boost on the line. And it'd also shift faster causing less turbo lag and basically you'd stay in boost?

[Rookie_ca18]

That didnt read how I wanted it to, what I was saying is if the psssht sound gets annoying then stay off boost, then when I said "i could see your point" I only meant why have a turbo car to stay off boost. I dont see anything wrong with having an auto. I personally wouldnt drive a auto turbo only because you wouldnt be able to have as much fun, i.e. down shifting...yeah thats about all I can think of right now but its late so you'll have to excuse me. Good luck on whatever you choose auto or manual. G'nite

[f s t caz]

You guys never get tired of the BOV sound? I know since Ive never driven a turbo car before, I'd enjoy the sound at first, but wouldnt it get tiring after a while?

i get tired of my hks quite often.

[iliketocrash]

hmm??

And whats so bad about automatic turbo anyway? Wouldnt it mean you could build boost on the line. And it'd also shift faster causing less turbo lag and basically you'd stay in boost?

well there is a relatively cheap electronic unit which allows you to build boost on the line even with a manual transmission. I don't know about the auto trannies that the ca18det uses but considering its age and who knows if someone has beat on it, i'm pretty sure i can shifter faster than it.

[Rookie_ca18]

Well the good thing about an auto is you dont have to worry about human error while shifting, but on the other hand you cant really control your shift points. I think while racing you have a bit more of an advantage using a manual because you can get the most out of the rpm band, where as an auto the car is just gonna shift wherever its programmed to. Also depending on the condition of the auto transmission usually the auto will shift faster than a human being can. Thats just my $0.02

[TeckniX]

so maybe I'm not understanding all this, but isn't the bov suppose to remove unwnated boost, yet if you recirc it, then you basically throw back in the boos you were just trying to get rid of? Maybe I need to do some reading again.. :\

[Rookie_ca18]

think of it as pressurised air, rercircing it is not throwing "boost" back into it...its no longer underpressure...you recirc it so you dont vent already metered air causing your motor to run rich. So by ricircing it you just put it back in after the maf. I might not be making much ( if any) sense so I'll let some1 far more educated in this matter than I answer this.

[rico05]

Sorry to bring this off page 2, but I have an update that is relivent.

I just installed my ARC Type 3 BOV. Sounds VERY nice (kind whistly at partial throttle shifts, and nice solid WHOOSH on quick, full boost shifts.) I have noticed that:#1: Decelerating then hitting it SUCKS. BOV vents as I decel, and it freaks out the ECU to give sudden boost to it. #2: Backfires a lot #3: Stumbles at idle even though tightened all the way.

Summary: Driveablity has suffered...for the sake of noise.I am going to recurric it then get my damn hard pipes made so I can run blow through MAF cuz vented just sounds GREAT. Just my now hands on real life $.02...

[float_6969]

Thanks for the info rico. I'd really like to know how the blow through setup works for you. I've heard about doing that way so you can vent atmos. But I've only seen one person do it and it was on a KA-T and he didn't keep it that way cus he had it rigged up, just to see if it would work. When you do it, start a new thread as I'd like to see what you think of it.