Ryan S Posted January 23 Report Share Posted January 23 Hello all, I know there’s been a couple debates on whether to run a BOV or not. I need more of a strait forward answer for my setup. overall I’m pretty stock. I have a down pipe, some holes in my air canister, and that’s pretty much it. I might turn up the boost to around 8 or 9 just to have a little more fun. recently I bought a CxRacing oversized IC, and a IC piping kit from MotoCam360 which is where my question begins. the cross over pipe has a 2 bolt flange for a Type-S or similar BOV. So what do you guys recommend I do/buy? I know that BOVs that vent only to atmosphere aren’t really that suitable for MAF cars, but I read on one forum that many people deal with the side effects. What are the side effects exactly? Just rough idle and running rich on decel? NGR has a nice BOV that has the same flange and it’s a newly designed leak free system, but I don’t think you can route it as a “hybrid” BOV. or do I just make a block off plate and skip the BOV? I’m not really scared about compressor surge, I know KEN said he’s been running without a BOV for a while and hasn’t snapped any shafts for damaged anything, and I like the sound more but I know running BOVs are beneficial in some way. also another question since I’m a noob when coming to turbo cars as this is my first one. Can I just run a manual boost controller in-line of the line that runs from the waste-gate to the cross over pipe, or do I also have to adjust the waste-gate? I’m not really sure how they function. Any suggestions would be amazing, thank you! Link to comment Share on other sites More sharing options...
tux Posted January 23 Report Share Posted January 23 So, with a MAF setup the classic knowledge is you have all this metered air, that is now gone. The ECU doesn’t know that air is gone so you’ll end running rich, throwing off your AFR’s. I run a BPV on my stock setup. Note there’s many BOV’s that can be plumbed to recirculate essentially activing as a bypass valve, if you use a bov as recirculating or use a bpv, you should just plumb that air back in after the MAF. My take is that this doesn’t matter that much for fueling, but the work was already performed to compress that air, so if you care about spool, put the air back. Rally cars recirculate to help keep the spool going. Link to comment Share on other sites More sharing options...
Ryan S Posted January 23 Author Report Share Posted January 23 2 minutes ago, tux said: So, with a MAF setup the classic knowledge is you have all this metered air, that is now gone. The ECU doesn’t know that air is gone so you’ll end running rich, throwing off your AFR’s. I run a BPV on my stock setup. Note there’s many BOV’s that can be plumbed to recirculate essentially activing as a bypass valve, if you use a bov as recirculating or use a bpv, you should just plumb that air back in after the MAF. My take is that this doesn’t matter that much for fueling, but the work was already performed to compress that air, so if you care about spool, put the air back. Rally cars recirculate to help keep the spool going. That makes more sense! Running rich would only happen on decel as that’s when the ECU doesn’t know the air is gone right? so if I bought the NGR BOV would I just route a hose from the side the air escapes to the hose after the MAF? Or how would I route a BOV to act as a BPV? also what BPV are you running? honestly I don’t care too much about spool, as it’s basically all stock and pretty slow lol. I’m not really gonna race many people. For me it’s more of a experience to drive a Starquest rather than racing it. Link to comment Share on other sites More sharing options...
tux Posted January 23 Report Share Posted January 23 I’m running a vintage hks bpv. The air recirculates after maf but before the turbo inlet. Here’s an example of a bov that can recirculate https://tialsport-outlet.com/products/tialsport-qr-series-recirculating-blow-off-valve-1-1 Link to comment Share on other sites More sharing options...
tux Posted January 26 Report Share Posted January 26 Just make sure to route after maf and before turbo Link to comment Share on other sites More sharing options...
Ryan S Posted January 26 Author Report Share Posted January 26 Sorry I haven’t replied yet, I was also doing a bit of research about how they work and now I have a clearer understanding. i was looking into some TurboSmart ones as some are a 50/50 split which is what I’d rather have. If I’m running a BOV I’m gonna want it to make some noise instead of being pretty silent. But $500 is dang steep for a BOV lol. I’m still debating what I want to do. thanks for your replies though! also does anyone else have any suggestions instead of just tux? Link to comment Share on other sites More sharing options...
tux Posted January 26 Report Share Posted January 26 Ultimately, it will be up to you what you decide and what you choice should be inline with your goal Link to comment Share on other sites More sharing options...
1SICDSM Posted January 27 Report Share Posted January 27 basically your getting cool bov noises and longevity of the turbo or cool surge noise and less turbo life.you can go either way no big deal.i ran a hks sequential vented to air no driveability issues. Link to comment Share on other sites More sharing options...
Ryan S Posted January 29 Author Report Share Posted January 29 On 1/26/2026 at 2:43 PM, tux said: Ultimately, it will be up to you what you decide and what you choice should be inline with your goal Yeah I know lol, I mean for now it’ll be pretty stock as I just don’t wanna dive into that rabbit whole. I would like to figure out a BOV setup but right now I think I’ll just make a plate until I figure out what kind of BOV to go with. thanks for your replies! Link to comment Share on other sites More sharing options...
Ryan S Posted January 29 Author Report Share Posted January 29 On 1/27/2026 at 7:02 AM, 1SICDSM said: basically your getting cool bov noises and longevity of the turbo or cool surge noise and less turbo life.you can go either way no big deal.i ran a hks sequential vented to air no driveability issues. Yeah I know how they work lol, was yours vented only to atmosphere? Or was it split. Cause I would go that route but I’ve read that some people have drivability issues? thanks for your response! Link to comment Share on other sites More sharing options...
1SICDSM Posted January 29 Report Share Posted January 29 mine was blowing off completely to atmosphere no issues at all. Link to comment Share on other sites More sharing options...
techboy Posted January 31 Report Share Posted January 31 I had a 1G BOV installed on my car since I built it and I had running rich and driveability issues for years I could never figure out. I tackled the throttle body and tried different injector setups and could just never get the car to run right. Finally, I think it was kev who said you know those 1G BOV are known to leak? Try recirculating it. I made up a temp recirculation and it fixed all my problems instantly. I was losing metered air and ECU was going bonkers I guess. I came up with a more permanent solution and have run it ever since. I can post some pics of how I did it tomorrow. Link to comment Share on other sites More sharing options...
Ryan S Posted February 2 Author Report Share Posted February 2 On 1/30/2026 at 10:26 PM, techboy said: I had a 1G BOV installed on my car since I built it and I had running rich and driveability issues for years I could never figure out. I tackled the throttle body and tried different injector setups and could just never get the car to run right. Finally, I think it was kev who said you know those 1G BOV are known to leak? Try recirculating it. I made up a temp recirculation and it fixed all my problems instantly. I was losing metered air and ECU was going bonkers I guess. I came up with a more permanent solution and have run it ever since. I can post some pics of how I did it tomorrow. Hmm, ok. I’ll probably end up going with that NGR BOV as you can utilize it to recirculate, and it’s leak free. thanks! Link to comment Share on other sites More sharing options...
Recommended Posts