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Retired Turbo Slut
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Discussion Starter · #1 · (Edited)
just wonderin if there was anyway around buying a bypass valve and getting a bov. I did talk to jim wolf and they said it's not possible, but i wondering if anyone gave it a shot. Correct me if im wrong, that you loose pressure in the intake when this performed causing the car to stall. Any insite??
 

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Retired Turbo Slut
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Discussion Starter · #3 ·
a bypass valve recirulates the compressed air from the throttle body pipe back to the intake. In stead of this, i was wondering if you could use a blow off valve that vents this air to the atmosphere
 

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no its not possiable there isnt enought pressure even to get the BOV to make any sounds....plus yes you will have problems stalling ..
 

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What's ur defintion of a bypass valve and a blow off valve to you?I think you're talking about the same thing. You're just asking if you can vent the blow off valve to the atmosphere.

Well in order to understand why JWT says you don't want to do this you have to understand how the turbo system works. Nissan's setup is a nice setup simply because the system reads how much air and at what temp that this air is being brought in. So now the ecu sees how much air is brought in, lets just say for example it sees 5 units of air. Then ecu then adds the right amount of fuel for 5 units of air.

Now you're driving along and everything is fine. Now you close the throttle. Where is this 5 units of air going? Well it's going to smack into the throttle plate and then work it's way back and smack into the spinning blades of the turbo. In extreme cases this revision of air can actually stop or reverse the turbo blades. Now blow off valves allow this air to escape so it doesn't bounce back and forth. Now on nissans the problem is that if you vent the 5 units of air out then the ecu has still added the right amount of fuel for 5 units of air, this results in a very rich air/fuel mixture. Resulting in an rich run, and since you are letting go of the gas and the motor is going to stumble a stall here is very possible. JWT gets around this by having a blow off valve, but having this blow off valve vent back into the intake stream, thus keeping the air in loop.

I have a stock nissan sr20det blow off valve, I have this rerouted back into the intake stream. Even at only 3-4 psi the sound was very audible from inside the car. It wasn't very loud from the outside which was fine with me.

UltimaSE
 

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If you really want to get the PSSSSHT sound, you have 3 options.

1. The Apex'i Super-AFC has the "DECEL-AIR" function that pretty much makes the ECU ignore the MAF readings when the BOV vents to atmosphere, and prevents stalling.

2. Get an adjustable BOV (one that lets you set the release pressure) e.g. HKS SSQV so that it doesn't leak on idle like the stock SR20DET Recirc valve does.

3. Get a hybrid BOV, one that sends enough air back into the system to keep the ECU happy, and sends some air outside to keep you happy. Check out www.gofastbits.com for an example of the hybrid.

The stock recirc valve leaks a lot at idle and makes the car run like shit if you vent to atmos., even with a S-AFC. From my experience though, the SSQV works pretty well by itself, but I use the S-AFC as well and don't have any idling or stalling problems. My engine is SR20DET, ymmv.

-rw
 

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Incognito
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1,388 Posts
a bypass valve is for a cai, it bypasses any water that may have sprayed into the intake. a BOV is pretty stupid without a turbo, kinda just like a poser, you hear this hissing sound and then the guy races you and you get smoked. people love racing turbo'ed engines, believe me, everyone thinks they can take down a turbo with a zc engine.
 

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Behold the Power of HID!!
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I did a search!!! :D Do any of the Turbo "wizards" have an opinion on this hybrid BOV that DRY mentioned? Would it work for our application? Would it actually make an audible noise?

dry said:
If you really want to get the PSSSSHT sound, you have 3 options.

1. The Apex'i Super-AFC has the "DECEL-AIR" function that pretty much makes the ECU ignore the MAF readings when the BOV vents to atmosphere, and prevents stalling.

2. Get an adjustable BOV (one that lets you set the release pressure) e.g. HKS SSQV so that it doesn't leak on idle like the stock SR20DET Recirc valve does.

3. Get a hybrid BOV, one that sends enough air back into the system to keep the ECU happy, and sends some air outside to keep you happy. Check out www.gofastbits.com for an example of the hybrid.

The stock recirc valve leaks a lot at idle and makes the car run like shit if you vent to atmos., even with a S-AFC. From my experience though, the SSQV works pretty well by itself, but I use the S-AFC as well and don't have any idling or stalling problems. My engine is SR20DET, ymmv.

-rw
 

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A BOV only let's off when you let off the throttle. IN order to even get the bwooosh or thweeeet you have to have enough pressure to do so. A car with no turbo that has a BOV is pointless. Just picture yourself holding a full balloon and suddenly releasing it, your fingers represent the BOV.
 

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Import Tech.
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We ran a greddy BOV on my brothers G20 and it released to the atmosphere ... I would say you had to get the adjustment just right or it would die at times at idle ...... But it can be done with an aftermarket unit with a fairly stiff spring !!!
 

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Is it the MAF you're worried about? The turbo kit you get should have a bypass that should take care of it maybe a reprogrammed ECU or something. I could be wrong.
 

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Behold the Power of HID!!
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The Fmax kit comes with an HKS bybass valve...which sends excess air to the downpipe instead of the atmosphere...causing liitle noise....Im trying to build a custom setup that would include some sort of BOV which would vent to the atmosphere...for that lovely sound!
 

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The fmax kit vents the blow off back into the intake track, not the downpipe. Since the air is still in the intake loop the maf is still accurate, and the car does not stumble. There are ways around this I think one of the apexi add on units might be able to solve this problem, and I know of at least one other idea that might work, but I'm no longer in contact with the guy trying it. Seems like a whole lot of trouble just for some noise.

My opinion? You can still hear the blow off valve when it opens back into the intake tract. It's not super loud but then why would you want it to be? Those who are listening for it and know what it is will know, those who don't well they're going to get blown away. Those who want to hear it ie, police will hear it and will know what it is.

UltimaSE
 

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Behold the Power of HID!!
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True....i know venting to the down pipe didnt sound right....but i wanna be different, thats y i wanna put together a turbo instead of buyin the FMax kit! I'll probably use some of their parts though! But that Hybrid BOV from Gofastbits.com...seems to be the answer to my question...jus wondering if anyone else has read up on it??

UltimaSE said:
The fmax kit vents the blow off back into the intake track, not the downpipe. Since the air is still in the intake loop the maf is still accurate, and the car does not stumble. There are ways around this I think one of the apexi add on units might be able to solve this problem, and I know of at least one other idea that might work, but I'm no longer in contact with the guy trying it. Seems like a whole lot of trouble just for some noise.

My opinion? You can still hear the blow off valve when it opens back into the intake tract. It's not super loud but then why would you want it to be? Those who are listening for it and know what it is will know, those who don't well they're going to get blown away. Those who want to hear it ie, police will hear it and will know what it is.

UltimaSE
 

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Turbo SE-R
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Hey i have a sr20det im my sentra and i vent into the atmosphere . The thing is that the maf can not read this air so when venting , and the car runs realy lean, and damages the rings on the pistons, so i do not recomend this unless u have a apexi s-afc it has a function mentioned already this fools the ecu providing the right air fuel ratio.. also if u want the loudest blow off valve get a blitz super sound loud as hell... PS building a custom kit will cost u more that a f-max kit trust me been there....kesi24
 

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Behold the Power of HID!!
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How exactly will it cost more?? Labor?? I really dont mind...since if i do it custom...i can get the parts as the money is available....The cheapest way is not always the best way! :D
 

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kesi24 said:
Hey i have a sr20det im my sentra and i vent into the atmosphere . The thing is that the maf can not read this air so when venting , and the car runs realy lean, and damages the rings on the pistons, so i do not recomend this unless u have a apexi s-afc it has a function mentioned already this fools the ecu providing the right air fuel ratio.. also if u want the loudest blow off valve get a blitz super sound loud as hell... PS building a custom kit will cost u more that a f-max kit trust me been there....kesi24

It shouldn't run lean. If anything it should run too rich. The ECU will think there's more air than is actually in the system, since some has been vented out to atmosphere, so should put more fuel than it really needs.

-rw
 

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Senior Member: Turbo '94
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I think that some of "gofastbits"'s info is strictly for selling the items. There are many things they say that are quite contrary to what I have learned and experienced as far as a turbo motor setup.

The claim of keeping air cool by venting hot air for example, well, during the process of bypassing (off throttle, lift throttle), the throttle is closed and so this hot air supposedly going into the engine, is really not doing anything for power in the first place.

I think if you really want sound, the AFC is the way to go.

Tunerguy

http://www.altimas.net/gal67.htm
 

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Behold the Power of HID!!
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Tunerguy said:
I think that some of "gofastbits"'s info is strictly for selling the items. There are many things they say that are quite contrary to what I have learned and experienced as far as a turbo motor setup.

The claim of keeping air cool by venting hot air for example, well, during the process of bypassing (off throttle, lift throttle), the throttle is closed and so this hot air supposedly going into the engine, is really not doing anything for power in the first place.

I think if you really want sound, the AFC is the way to go.

Tunerguy

http://www.altimas.net/gal67.htm
Thanx alot...I knew people would have pics!! So in your opinion you dont think their Hybrid valve would work as advertised? Looks to me like it would work.....then again im not an expert! Maybe I can be their guinea pig! LOL

P.S. The reason why im not to fond of the AFC idea is because im trying to keep the gauges to a minimum inside my car...dont want it to look like a freakin airplane cockpit!! I'm already gonna use Apexi's Turbo Controller plus like 2-3 gauges...dont even know where to put an AFC if i would get one also!
 
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