Converted my bypass valve to a bov
 

So i converted my bypass valve to vent to the atmospher. i had absolutely no sound before i did it and now it sounds good but not too loud. just thought i'd share.

i like the way it sounds though. :mrgreen: :driving:

Neat, wish I could get away with something like that, but my ecu would have a fit.

*kicks ecu*
*check engine light comes on*

DAMN IT!

Anyway, I don't if you did this or not, but you should put some kind of a filter on the open BOV. Reason being the BOV is open when the car is idling and you don't want it to suck up dirt or anything else while it's open.

I have an hks ssqv bov, and an intake for you if your interested, cause im almost positive that a 97' 900 turbo is the same as a 99' 9'3 turbo. Sounds crazy, LOL the turbo is louder than the evo's and im only maxin 8 psi. Let me know, its still on the car if you want to hear it first.

Don't be too upset! This mod is pretty much useless anyway, that is unless you worry about what kind of neat sounds your car makes.

I'll post a picture in a couple minutes of why on any MAS car this is a poor idea.

That being said, My car has a MAS and the BOV vented, which is how I can show you why not to do it.

http://people.clemson.edu/~nanthon/misc/vented_bov.jpg

This is a picture showing RPM vs A/F. As you can see in the picture, after every shift with the vented BOV, the car goes rich to 10.5:1, then as the airflow catches back up, it gets back into the ~12:1 range. The lean spikes right before a shift and right before the finish line are from when I ran out of air metering with the stock MAS. Yes, I know this tune wasn't the greatest but it shows why venting a BOV is not a good idea and it also netted 127 MPH in the quarter.

I was just making fun of how easily my ecu, known as the Trionic 7, throws a fit. It uses a AFM and a MAP together is some crazy way to get the perfect mix (it really does run great, but it's fickel). Now he's got a Trionic 5, which I think only uses a MAP so it should be fine, but don't quote me on that.

SO how much for just the blow off valve?

I did alot of research before I touched the car, and the t-5 seemed to run trouble free with vta and an open intake...And its been like this for almost 2 years, and this car has never given me a problem( cross my fingers).

Pm me if your really interested, ill hook you up.

I didn't realize some Saabs did that. I have heard of peopl doing that with aftermarket tuning solutions (e-manage, etc). I can imagine that if the MAF is see X amount of air and then it is blown-off and the MAP sees only a fraction of that then the ECU would freak!

Another option (if you want the sound) is to buy a BOV, such as a Greddy type s, and modify it so that it will open at idle. This makes it run like a bypass valve. A friedn has one set up like this on his car and it still makes a decent amount of noise even thous it is recicrulated.

No no, I'm good, I fitted an open element intake. Even with the original recirculating system I get a fantastic blow-off-like noise. :) Just bitching about my impossible to mod ecu.

what Driven posted up may be true on some cars when venting the BOV into the atmosphere, but I can tell you that on my SR and on my Skyline, which both had atmospheric BOVs, that i didn't have any problems with my AFRs what so ever

what you (Driven) had experienced may be an issue with DSMs that's not necessarily an issue with Nissans

now, that being said, i do know that there are a few SRs out there that stall at idle with an atmospheric BOV, but this is not a very comon occurence, and can always be resolved by adjusting the AIR DEC settings on an SAFC II

Late,
Daniel

Are they MAS cars with the metering before the BOV? If so, any car should do this (not that its the right thing to do, but its how MAS cars work). MAP sensor cars on the other hand shouldn't have problems. MAS cars with the MAS after the BOV also shouldn't have problems.

the MAF on SRs and RBs is right after the filter in the intake piping before the turbo.....the BOVs are placed in the hotpipe