Blow-off valves
02-01-2008, 07:32 AM
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Blow-off valves
Since there's no dedicated thread on this, I'd like to know what BOV's you're running. and I mean just that, Blow-off, not bypass. I'm fairly well educated about turbo engines and the likes, being that I'm a regular on NASIOC.com and had a WRX for a while.
I just think the idea of an SUV with the blow-off valve sound is stupidly hilarious and I wanna do it. Yes, I know the engine accounts for that air and therefore will run rich for a very short time after a vent to the atmosphere, but I really don't care. When you're causing a blow-off, you're generally off-throttle, so a rich condition for a short moment isn't really going to cause that much of an issue, IMO.
Anyway, I'm interested to see what you've got and if it required any modification to make it work on your RDX.
I just think the idea of an SUV with the blow-off valve sound is stupidly hilarious and I wanna do it. Yes, I know the engine accounts for that air and therefore will run rich for a very short time after a vent to the atmosphere, but I really don't care. When you're causing a blow-off, you're generally off-throttle, so a rich condition for a short moment isn't really going to cause that much of an issue, IMO.
Anyway, I'm interested to see what you've got and if it required any modification to make it work on your RDX.
02-01-2008, 10:18 AM
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Stock, but I agree, it would be stupidly hilarious and would be a blast! It would be nice to here the turbo a little more. Keep us posted on what you decide to do.
02-01-2008, 10:21 AM
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I vaguely remember someone posting that a aftermarket bov could actually be better then the stock due the stock ones leaking? And there was something about the CX-7's bov leaking and if the rdx's is similar it is leaking too...
Sorry im a turbo noob. Please do enlighten the noob's on the pros and cons of a BOV.
Thanks
Sorry im a turbo noob. Please do enlighten the noob's on the pros and cons of a BOV.
Thanks
02-01-2008, 10:29 AM
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There really aren't any pros to a BOV and anybody who tells you there is is lying to you.
If you don't know what they do, a BOV or in our case, a BPV (bypass valve) allows the pressure built up from the turbo to exhaust somewhere other than trying to go into the engine when you let off the throttle or shift. If the engine wants to accelerate and you have air being forced in, that's great. However, if air is trying to be forced in yet your engine is decelerating, that's a problem and will cause serious damage. So a blow-off or bypass valve give that pressurized air somewhere to go other than smashing into the cylinders in your engine.
A blow-off valve allows the air to just vent into the atmosphere, so you will generally hear a quick burst of air whooshing out. Most factory turbo cars have a bypass valve which vents that air back into your intake box.
Because of that, cars generally have already accounted for that air in their air/fuel mixture to allow the engine to continue running at the proper ratios. If you have a blow-off valve in place of a BPV, you're losing that air that's already been accounted for by the engine management system.
Now, that said. The stock BPV is, from what I've heard, the same as the CX-7's. It's apparently made of mostly plastic instead of metal and fairly flimsy. It is possible that the spring holding the valve shut under normal boost isn't strong enough to resist that pressure, so you get boost-leak. That means not all that pressurized air is going into the cylinders as it should.
so in theory, if that happens, most BOV's will have a stronger spring which will not allow boost leak, or as many call it, boost creep.
I have no idea if the stock BPV valve leaks, and I don't care. The whooshing sound you often hear from kids in their neons and WRXs is exactly what I want to mimic, just to basically make fun of them. Plus, the first time you hear it when you're driving, you can't help but to titter like a little girl.
If you don't know what they do, a BOV or in our case, a BPV (bypass valve) allows the pressure built up from the turbo to exhaust somewhere other than trying to go into the engine when you let off the throttle or shift. If the engine wants to accelerate and you have air being forced in, that's great. However, if air is trying to be forced in yet your engine is decelerating, that's a problem and will cause serious damage. So a blow-off or bypass valve give that pressurized air somewhere to go other than smashing into the cylinders in your engine.
A blow-off valve allows the air to just vent into the atmosphere, so you will generally hear a quick burst of air whooshing out. Most factory turbo cars have a bypass valve which vents that air back into your intake box.
Because of that, cars generally have already accounted for that air in their air/fuel mixture to allow the engine to continue running at the proper ratios. If you have a blow-off valve in place of a BPV, you're losing that air that's already been accounted for by the engine management system.
Now, that said. The stock BPV is, from what I've heard, the same as the CX-7's. It's apparently made of mostly plastic instead of metal and fairly flimsy. It is possible that the spring holding the valve shut under normal boost isn't strong enough to resist that pressure, so you get boost-leak. That means not all that pressurized air is going into the cylinders as it should.
so in theory, if that happens, most BOV's will have a stronger spring which will not allow boost leak, or as many call it, boost creep.
I have no idea if the stock BPV valve leaks, and I don't care. The whooshing sound you often hear from kids in their neons and WRXs is exactly what I want to mimic, just to basically make fun of them. Plus, the first time you hear it when you're driving, you can't help but to titter like a little girl.
02-08-2008, 07:22 AM
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I totally agree. I have an RDX and sold my STI and WRX wagon and I NEEEEED this! I have two HKS SSQBOV's and a Greddy Type S BOV in my garage just itching to be adapted to my RDX.
I want to make this happen!!
I want to make this happen!!
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02-12-2008, 02:39 PM
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Originally Posted by JGard
If you don't know what they do, a BOV or in our case, a BPV (bypass valve) allows the pressure built up from the turbo to exhaust somewhere other than trying to go into the engine when you let off the throttle or shift. If the engine wants to accelerate and you have air being forced in, that's great. However, if air is trying to be forced in yet your engine is decelerating, that's a problem and will cause serious damage. So a blow-off or bypass valve give that pressurized air somewhere to go other than smashing into the cylinders in your engine.
Let's address one thing first. The BOV/BPV does relieve excess pressure in the form of a vent to atmosphere or a recirculation.
The reason it does is this because when you let off the throttle, your throttle body closes. If it closes in the midst of making boost you have pressure that needs to go somewhere and it's not going into the engine. Well the only place it can go without a BOV/BPV is back into the turbo. This is generally a bad thing and can cause surging/stalling.
Overtime this can cause premature turbo wear. This is where your BOV/BPV helps out, it either routes the excess air to the atmosphere and makes a "cool" noise, or routes it back into the intake system allowing it to safely return to the turbo via the inlet.
Problem with many VTA BOVs is if they're installed on a MAF car. They let metered air out of the system causing the car to run richer than it should at the point when the venting occurs. This generally doesn't cause a major issue, but in general the car will run better with a recirc valve if that's what the car has been designed with (assuming the stock unit isn't junk).
02-19-2008, 04:45 PM
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Are you sure you guys want to do this to your nice, refined, luxury RDX? It might be cool in an STi or Evo, but RDX? I'm not so sure.
http://www.youtube.com/watch?v=fbGq-fsGTHE
http://www.youtube.com/watch?v=fbGq-fsGTHE
02-19-2008, 06:10 PM
#13
Originally Posted by scottRDX
Are you sure you guys want to do this to your nice, refined, luxury RDX? It might be cool in an STi or Evo, but RDX? I'm not so sure.
http://www.youtube.com/watch?v=fbGq-fsGTHE
http://www.youtube.com/watch?v=fbGq-fsGTHE
I agree. I didn't even wnat to do that to my GTI.
02-19-2008, 06:11 PM
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Scott: It's the irony and hilarity I'm going for
One of my friends and his TurboXS BOV will fit if I get a new flange from TurboXS. So I think for now I'm going to search for Mazdaspeed BOVs
One of my friends and his TurboXS BOV will fit if I get a new flange from TurboXS. So I think for now I'm going to search for Mazdaspeed BOVs
02-19-2008, 07:39 PM
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Originally Posted by JGard
Scott: It's the irony and hilarity I'm going for
One of my friends and his TurboXS BOV will fit if I get a new flange from TurboXS. So I think for now I'm going to search for Mazdaspeed BOVs
One of my friends and his TurboXS BOV will fit if I get a new flange from TurboXS. So I think for now I'm going to search for Mazdaspeed BOVs
looks like the same flange. you can pick one up from www. CP-E.com or almost anywhere. the question is, will it fit ? not sure ...
02-21-2008, 09:44 AM
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Originally Posted by kaereachi
I sometimes wonder if pedestrians can hear the hissing as well when I cut them off in the crosswalk making a right turn.
02-22-2008, 02:33 AM
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I was looking for a "bov" or something of the kind for the last year. What I finally decided to do and yielded a huge "bov" sound... I modified the top of the oem airbox, basicly leaving only the maf housing and tube (which is 3" diameter) and mounting an intake filter to it. The intake filter than sits inside the lower portion of the oem aibox and still gets the fresh outside air blowing on it from the ducts. (I was worried about heat soak). The turbo sound is very noticable now and the whole project cost me about $45 with a new filter and spare oem top airbox piece.
08-12-2009, 02:10 AM
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BOV's are hard because they will throw a CEL. A By-pass valve (BPV) will continue to recirculate the air. Aftermarket BPV will get a similar sound effect with BOVs.
12-30-2009, 04:00 PM
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I kinda did, but without proper tuning there's problems. So I had to revert back the stock BPV with silicone tubing.
12-31-2009, 12:15 PM
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I worked with Forge since the Mazda CX-7 shared a similar engine. It was just a matter of tuning it with the springs and shims. I started a thread about it, link below.
https://acurazine.com/forums/1g-rdx-problems-fixes-160/backfiring-741174/
https://acurazine.com/forums/1g-rdx-problems-fixes-160/backfiring-741174/
01-03-2011, 06:34 PM
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There really aren't any pros to a BOV and anybody who tells you there is is lying to you.
If you don't know what they do, a BOV or in our case, a BPV (bypass valve) allows the pressure built up from the turbo to exhaust somewhere other than trying to go into the engine when you let off the throttle or shift. If the engine wants to accelerate and you have air being forced in, that's great. However, if air is trying to be forced in yet your engine is decelerating, that's a problem and will cause serious damage. So a blow-off or bypass valve give that pressurized air somewhere to go other than smashing into the cylinders in your engine.
A blow-off valve allows the air to just vent into the atmosphere, so you will generally hear a quick burst of air whooshing out. Most factory turbo cars have a bypass valve which vents that air back into your intake box.
Because of that, cars generally have already accounted for that air in their air/fuel mixture to allow the engine to continue running at the proper ratios. If you have a blow-off valve in place of a BPV, you're losing that air that's already been accounted for by the engine management system.
Now, that said. The stock BPV is, from what I've heard, the same as the CX-7's. It's apparently made of mostly plastic instead of metal and fairly flimsy. It is possible that the spring holding the valve shut under normal boost isn't strong enough to resist that pressure, so you get boost-leak. That means not all that pressurized air is going into the cylinders as it should.
so in theory, if that happens, most BOV's will have a stronger spring which will not allow boost leak, or as many call it, boost creep.
I have no idea if the stock BPV valve leaks, and I don't care. The whooshing sound you often hear from kids in their neons and WRXs is exactly what I want to mimic, just to basically make fun of them. Plus, the first time you hear it when you're driving, you can't help but to titter like a little girl.
If you don't know what they do, a BOV or in our case, a BPV (bypass valve) allows the pressure built up from the turbo to exhaust somewhere other than trying to go into the engine when you let off the throttle or shift. If the engine wants to accelerate and you have air being forced in, that's great. However, if air is trying to be forced in yet your engine is decelerating, that's a problem and will cause serious damage. So a blow-off or bypass valve give that pressurized air somewhere to go other than smashing into the cylinders in your engine.
A blow-off valve allows the air to just vent into the atmosphere, so you will generally hear a quick burst of air whooshing out. Most factory turbo cars have a bypass valve which vents that air back into your intake box.
Because of that, cars generally have already accounted for that air in their air/fuel mixture to allow the engine to continue running at the proper ratios. If you have a blow-off valve in place of a BPV, you're losing that air that's already been accounted for by the engine management system.
Now, that said. The stock BPV is, from what I've heard, the same as the CX-7's. It's apparently made of mostly plastic instead of metal and fairly flimsy. It is possible that the spring holding the valve shut under normal boost isn't strong enough to resist that pressure, so you get boost-leak. That means not all that pressurized air is going into the cylinders as it should.
so in theory, if that happens, most BOV's will have a stronger spring which will not allow boost leak, or as many call it, boost creep.
I have no idea if the stock BPV valve leaks, and I don't care. The whooshing sound you often hear from kids in their neons and WRXs is exactly what I want to mimic, just to basically make fun of them. Plus, the first time you hear it when you're driving, you can't help but to titter like a little girl.
01-04-2011, 04:57 PM
#31
There really aren't any pros to a BOV and anybody who tells you there is is lying to you.
If you don't know what they do, a BOV or in our case, a BPV (bypass valve) allows the pressure built up from the turbo to exhaust somewhere other than trying to go into the engine when you let off the throttle or shift. If the engine wants to accelerate and you have air being forced in, that's great. However, if air is trying to be forced in yet your engine is decelerating, that's a problem and will cause serious damage. So a blow-off or bypass valve give that pressurized air somewhere to go other than smashing into the cylinders in your engine.
A blow-off valve allows the air to just vent into the atmosphere, so you will generally hear a quick burst of air whooshing out. Most factory turbo cars have a bypass valve which vents that air back into your intake box.
Because of that, cars generally have already accounted for that air in their air/fuel mixture to allow the engine to continue running at the proper ratios. If you have a blow-off valve in place of a BPV, you're losing that air that's already been accounted for by the engine management system.
Now, that said. The stock BPV is, from what I've heard, the same as the CX-7's. It's apparently made of mostly plastic instead of metal and fairly flimsy. It is possible that the spring holding the valve shut under normal boost isn't strong enough to resist that pressure, so you get boost-leak. That means not all that pressurized air is going into the cylinders as it should.
so in theory, if that happens, most BOV's will have a stronger spring which will not allow boost leak, or as many call it, boost creep.
I have no idea if the stock BPV valve leaks, and I don't care. The whooshing sound you often hear from kids in their neons and WRXs is exactly what I want to mimic, just to basically make fun of them. Plus, the first time you hear it when you're driving, you can't help but to titter like a little girl.
If you don't know what they do, a BOV or in our case, a BPV (bypass valve) allows the pressure built up from the turbo to exhaust somewhere other than trying to go into the engine when you let off the throttle or shift. If the engine wants to accelerate and you have air being forced in, that's great. However, if air is trying to be forced in yet your engine is decelerating, that's a problem and will cause serious damage. So a blow-off or bypass valve give that pressurized air somewhere to go other than smashing into the cylinders in your engine.
A blow-off valve allows the air to just vent into the atmosphere, so you will generally hear a quick burst of air whooshing out. Most factory turbo cars have a bypass valve which vents that air back into your intake box.
Because of that, cars generally have already accounted for that air in their air/fuel mixture to allow the engine to continue running at the proper ratios. If you have a blow-off valve in place of a BPV, you're losing that air that's already been accounted for by the engine management system.
Now, that said. The stock BPV is, from what I've heard, the same as the CX-7's. It's apparently made of mostly plastic instead of metal and fairly flimsy. It is possible that the spring holding the valve shut under normal boost isn't strong enough to resist that pressure, so you get boost-leak. That means not all that pressurized air is going into the cylinders as it should.
so in theory, if that happens, most BOV's will have a stronger spring which will not allow boost leak, or as many call it, boost creep.
I have no idea if the stock BPV valve leaks, and I don't care. The whooshing sound you often hear from kids in their neons and WRXs is exactly what I want to mimic, just to basically make fun of them. Plus, the first time you hear it when you're driving, you can't help but to titter like a little girl.
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