Stock ABV
08-19-12 | 06:55 PM
#1
Thread Starter
Turbo Power
Joined: Jul 2009
Posts: 224
Likes: 1
From: Vancouver Island BC
Stock ABV
So I have a 93 twin set up pretty much stock, cai cat back. When I'm driving thru any gear i can hear air coming out of my abv except under wot anything under that then I can hear it leaking and have very little to no boost, unless I'm clock to wot, example: driving around and modderate excellerating in 3rd gear about 3k around 60km? I barly have boost maybe a few psi and I can hear a rushing of air, but if I hit the throttle it builds boost all the way to 10-8-10 or so. Just wondering if that's normal or if its bad. Also when idling in neutral when I was under the hood I could feel air being pushed out( my abv are un hooked from the intakes) and if I rev it up it pushes more out, only when I smash the cable it builds up and discharges in a nice blast
08-19-12 | 08:23 PM
#3
Oil pressure gauge O_O
About the ABV, Your description sounds like a leak. Once, my CRV hose had a small split, and I could only see the hole by bending the hose. I'm sure that 8psi on the walls would apply a similar force to open the crack, so it's probably a good idea to remove and inspect them.
About the ABV, Your description sounds like a leak. Once, my CRV hose had a small split, and I could only see the hole by bending the hose. I'm sure that 8psi on the walls would apply a similar force to open the crack, so it's probably a good idea to remove and inspect them.
08-19-12 | 08:27 PM
#4
Thread Starter
Turbo Power
Joined: Jul 2009
Posts: 224
Likes: 1
From: Vancouver Island BC
Something wrong with the oil pressure gauge? (stock one isn't hooked up, the gauge on the top of the pillar is my oil pressure? And I will do that once I'm home! Just left for camp 
08-19-12 | 11:27 PM
#5
10-8-10-8
Joined: Jan 2012
Posts: 845
Likes: 10
From: Australia
I asked your question about a year ago, and yes, the ABV (Air Bypass Valve?) does this in normal operation. User ARGHX explained it to me in a thread.
At idle, the stock ABV should suck air inwards. Crack the throttle a little bit with your hand, and you will feel air being blown out of the ABV. This is normal operation for the ABV.
The ABV does not have a piston inside it, like a normal BOV. The operation is different. The ABV has a diaphragm.
A conventional BOV has a piston which stays closed normally, until it vents a pressure surge, caused by the throttle plates closing, and a difference in vacuum signal either side of the throttle plates causes the BOV piston to move and exhaust. An ABV does not do this.
I have talked to Brett (head mech engineer) at GFB, here in Australia and know him personally. He designs the GFB range of BOVs. His opinion is that the factory ABV on many cars vents indiscriminatly in order to keep unwanted turbo flutter surge noises acceptable, as people who were paying $$$ for a new RX-7 didnt want weird flutter noises from their new cars.
Brett also advised that running an aftermarket BOV with the properly tensioned spring, might help build boost a tiny fraction of a billionth of a bit sooner, as unlike the ABV, a BOV is normally always closed during spool, and this may contribute to slightly earlier boost, but you would be unlikely to notice it.
In short, yes, if you search "stock BOV correct operation" in the 3rd Gen forum (or PM user ARGHX), you will find the thread. Your ABV is working as intended by the factory.
At idle, the stock ABV should suck air inwards. Crack the throttle a little bit with your hand, and you will feel air being blown out of the ABV. This is normal operation for the ABV.
The ABV does not have a piston inside it, like a normal BOV. The operation is different. The ABV has a diaphragm.
A conventional BOV has a piston which stays closed normally, until it vents a pressure surge, caused by the throttle plates closing, and a difference in vacuum signal either side of the throttle plates causes the BOV piston to move and exhaust. An ABV does not do this.
I have talked to Brett (head mech engineer) at GFB, here in Australia and know him personally. He designs the GFB range of BOVs. His opinion is that the factory ABV on many cars vents indiscriminatly in order to keep unwanted turbo flutter surge noises acceptable, as people who were paying $$$ for a new RX-7 didnt want weird flutter noises from their new cars.
Brett also advised that running an aftermarket BOV with the properly tensioned spring, might help build boost a tiny fraction of a billionth of a bit sooner, as unlike the ABV, a BOV is normally always closed during spool, and this may contribute to slightly earlier boost, but you would be unlikely to notice it.
In short, yes, if you search "stock BOV correct operation" in the 3rd Gen forum (or PM user ARGHX), you will find the thread. Your ABV is working as intended by the factory.
08-19-12 | 11:41 PM
#7
Thread Starter
Turbo Power
Joined: Jul 2009
Posts: 224
Likes: 1
From: Vancouver Island BC
I asked your question about a year ago, and yes, the ABV (Air Bypass Valve?) does this in normal operation. User ARGHX explained it to me in a thread.
At idle, the stock ABV should suck air inwards. Crack the throttle a little bit with your hand, and you will feel air being blown out of the ABV. This is normal operation for the ABV.
The ABV does not have a piston inside it, like a normal BOV. The operation is different. The ABV has a diaphragm.
A conventional BOV has a piston which stays closed normally, until it vents a pressure surge, caused by the throttle plates closing, and a difference in vacuum signal either side of the throttle plates causes the BOV piston to move and exhaust. An ABV does not do this.
I have talked to Brett (head mech engineer) at GFB, here in Australia and know him personally. He designs the GFB range of BOVs. His opinion is that the factory ABV on many cars vents indiscriminatly in order to keep unwanted turbo flutter surge noises acceptable, as people who were paying $$$ for a new RX-7 didnt want weird flutter noises from their new cars.
Brett also advised that running an aftermarket BOV with the properly tensioned spring, might help build boost a tiny fraction of a billionth of a bit sooner, as unlike the ABV, a BOV is normally always closed during spool, and this may contribute to slightly earlier boost, but you would be unlikely to notice it.
In short, yes, if you search "stock BOV correct operation" in the 3rd Gen forum (or PM user ARGHX), you will find the thread. Your ABV is working as intended by the factory.
At idle, the stock ABV should suck air inwards. Crack the throttle a little bit with your hand, and you will feel air being blown out of the ABV. This is normal operation for the ABV.
The ABV does not have a piston inside it, like a normal BOV. The operation is different. The ABV has a diaphragm.
A conventional BOV has a piston which stays closed normally, until it vents a pressure surge, caused by the throttle plates closing, and a difference in vacuum signal either side of the throttle plates causes the BOV piston to move and exhaust. An ABV does not do this.
I have talked to Brett (head mech engineer) at GFB, here in Australia and know him personally. He designs the GFB range of BOVs. His opinion is that the factory ABV on many cars vents indiscriminatly in order to keep unwanted turbo flutter surge noises acceptable, as people who were paying $$$ for a new RX-7 didnt want weird flutter noises from their new cars.
Brett also advised that running an aftermarket BOV with the properly tensioned spring, might help build boost a tiny fraction of a billionth of a bit sooner, as unlike the ABV, a BOV is normally always closed during spool, and this may contribute to slightly earlier boost, but you would be unlikely to notice it.
In short, yes, if you search "stock BOV correct operation" in the 3rd Gen forum (or PM user ARGHX), you will find the thread. Your ABV is working as intended by the factory.
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08-19-12 | 11:42 PM
#8
Thread Starter
Turbo Power
Joined: Jul 2009
Posts: 224
Likes: 1
From: Vancouver Island BC
