18+psi BOV

What type bov are you guy running with 18+psi of boost? Also where do you buy them and how much did you paid for? I want to use a bov on my blown 383LT1 motor. Any help is appreciate


Bruce

I'll be using one of these:

http://www.greddy.com/products/blowoffvalves_frame.htm

If you scroll down the page, you'll see a "relief valve". I'm not sure how this is used, but its function sounds the same as a BOV. I believe the units are off because 0.08 kg/mm2 (the low setpoint) equals almost 114 psi. I think the units should be kg/cm2, which makes the low setpoint 1.1 psi and the high ~28 psi. Maybe someone else can shed some light on this product.

Well I found quiet a few on the nets. But I am fall between the Apexi Bov and HKS SSQV

1)The Apexi bov have twin chamber and you can have an adjustable sound for extra loud.

2) HKS SSQV all it says is an aggressive sound. but not adjustable for loud.


Which one would you buy if you have to choose between the two?????? You input is appreciated.


Bruce

I am a firm believer that form follows function. I could care less about how a BOV sounds, only that it functions as efficiently as possible. After all, we don't decide on one only because it sounds "cool", do we? Of course, I can only speak for myself, so maybe you do???

I need one because when I let off the throttle at 23+ psig, I want that BOV to open as quickly as possible, period. And because I run two surge valves, this is the only time I want the BOV to open. Some clarification: My ATI surge valves do not open instantaneously when letting off the throttle. There is up to a one second (or so) delay. It's in that one second that I'm concerned that compressor surge will occur.

Willie

Stock blow off valve from a 90-94 DSM (Mitsu Eclipse, Plymouth Laser, Eagle Talon) should hold 18 psi. Turbo models only, obviously. Shouldn't cost more than $20 from a junkyard. :cool:
It doesn't sound as cool as the others, but it's a lot cheaper, and does the same thing.

Originally posted by andol469
Stock blow off valve from a 90-94 DSM (Mitsu Eclipse, Plymouth Laser, Eagle Talon) should hold 18 psi. Turbo models only, obviously. Shouldn't cost more than $20 from a junkyard. :cool:
It doesn't sound as cool as the others, but it's a lot cheaper, and does the same thing.

It may hold 18 psi on a dsm, but 18psi on a DSM, and 18psi on a V8 are two different things. I doubt it will flow enough CFM to be fully effective, although I'm just guessing at that.

I don't think it would matter so much if it was a v8 or a DSM. It's not a question of how much air is flowing necessarily, it's how much pressure is being exerted on a valve. Besides, the Apex and HKS mentioned in this thread are popular among DSMers. Those BOVs are designed for low displacement engines, but can be used on larger engines, so wouldn't the same hold true for a 1g BOV?

BTW, you can "mod" the BOV to hold upwards of 25 psi. http://www.thedodgegarage.com/turbo_bov_mod.html

Timbr SS was talking about CFM, not psi... I think he is right also. The stock blowoff from a DSM is probably a dinky little piece and will pose a restriction trying to let off all that CFM that turbo is pumping in the intake pipe.

Originally posted by 96 WS6
Timbr SS was talking about CFM, not psi... I think he is right also. The stock blowoff from a DSM is probably a dinky little piece and will pose a restriction trying to let off all that CFM that turbo is pumping in the intake pipe.

CFM isn't the issue here, it's the amount of pressure being exerted on the valve (psi.) The 90-94 stock BOVs aren't "dinky." The 95-99 DSM BOVs suck. If it's setup right, it shouldn't pose a restriction at all.

The $150 BOVs mentioned earlier in this thread work fine on DSMs. Even though the DSM flows less CFM, the amount of pressure being exerted on the valve is the same as it would be on a v8. If you're going to drop the cash on a HKS or Apexi BOV, just do it right the first time and get a Tial.

You are right, 18psi of pressure on a v8 is the same as 18psi on a I4 - so the valve that will work on one will also *hold* to that point on the other.

But once the valve is open there is a question of how long it takes to "vent" the boost. The 18psi on a V8 represents a much greater amount of air than on the I4, so through a fixed ortifice (BOV) and at a fixed pressure differential it will take much longer to vent out.

No if that's actually an issue or not i have no idea, but it definitely will take longer to vent.

Originally posted by Chris B
You are right, 18psi of pressure on a v8 is the same as 18psi on a I4 - so the valve that will work on one will also *hold* to that point on the other.

But once the valve is open there is a question of how long it takes to "vent" the boost. The 18psi on a V8 represents a much greater amount of air than on the I4, so through a fixed ortifice (BOV) and at a fixed pressure differential it will take much longer to vent out.

No if that's actually an issue or not i have no idea, but it definitely will take longer to vent.

True, but the same could be a problem with the HKS and Apexi BOVs that were mentioned in the above thread, as the HKS and Apexi units were not made to handle more than 30 psi of boost from 3.0 L I6 ;). I'm not saying a DSM BOV is necessarily the best choice, it's just as effective as the $150 Japanese brands and costs less.

I think the -best- choice would be to go with a Tial.

i would go with the Tial and just get it over with. I will hold alot of pressure and it will flow enough CFM for a 900 cubic inch BB with 6 turbos, 4 guns, and a rocket booster. The thing that I knew would happen as soon as I saw this thread was 1 someone will say something like "well that is for a 4 banger. A V8 is bigger and cooler and helps me make up for my penis size, so it wont work." Well a 1G DSM BOV will probbaly do the trick but we dont know his whoel setup so all we can do is guess. I do know that a Tial will be more than enough and is a very nice piece. I also think its funny that I see alot of people on this board say that almost everything that has a 4 cyl is rice, however one of the first questions was what BOV makes the most noise or is the loudest. Those are all typical ricer comments. Well thanls for the spave and letting me rant.


Michael

*Cough*Godzilla (http://www.geocities.com/kmook123/godzilla.html)*Cough*

Originally posted by boostedinaz
I knew would happen as soon as I saw this thread was 1 someone will say something like "well that is for a 4 banger. A V8 is bigger and cooler and helps me make up for my penis size, so it wont work."

I didn't see where anyone said that a V8 was better. When the DSM BOV was suggested, it seemed that the only cosideration was how much PSI it could hold. If that was the only thing that we needed to take into consideration, everyone would just run a solid pipe, cause we all know that would hold 100 PSI.

It didn't look like the CFM was being considered. 18PSI on a decent 383 is going to be at least 1000 CFM, most likely 1200+. Probably around 700rwhp or so. How much power/how many CFM is a DSM at 18 PSI?

I don't feel like looking up the numbers, but I'd guess that the same volume of air on the DSM at 18psi, would be less than 4psi, if # any at all, on a decent 383 LT1. (That's just an example, I'm content with my penis size.)

When you're flowing that much air, coming off WOT, when the throttle blades close, that's a decent amount of pressure on the compressor. I would guess at least 50 PSI if you didn't have a BOV at all. You want to vent as much off that off, as quick as possible, to prevent compressor surge.

I'm not a DSM "tuner", and don't really know much about the 1G BOV recomended. I just doubt that a BOV designed for a ~200whp car is going to flow 1kCFM

Anyways, after spending $8k+ on a blown 383 LT1, I wouldn't be too worried about spending another $250 for a decent BOV.

Nobody said the 1g BOV from a DSM is the best choice. I was just stating that if you're considering over-priced Japanese BOVs like the HKS, Greddy, Apexi, etc, it might be a better idea to take a look at a 1g BOV. That's all. I mentioned that a TiAL would be a good choice IMO.

Are there any considerations from the inertia of the valve itself - it would seem if you go with a much larger valve then it will take longer for it to open - possibly leading to compressor surging, etc.?

Would it be reasonable to run one large valve and one small one, or what that be a waste (i.e. it isn't an issue?)


Chris

I'm not a DSM "tuner", and don't really know much about the 1G BOV recomended. I just doubt that a BOV designed for a ~200whp car is going to flow 1kCFM




Thats exactly what I am saying. There are alot of people who use these BOV for alot of things not just a 200 hp 4 banger. They have been used on a good deal of 500 awhp DSM's. They are a very good BOV and thats whay they get used on a wide variety of vehicles big and small motors. They can handle high psi when crushed (25 psi) and flow a great deal of air, I am not sure on the exact CFM. I also wonder why no body know or seems to care what size turbo he is using or what his setup is. That has to do more with how much the BOV needs to flow that the size of the motor. If he is running a T88 then he will need a good deal of flow if he is runnign something smaller then he wont need as much. Again like it has been said before no one said that a DSM BOV is the only one or the best, but it is a cheap alternative that WILL work. What we lack in CI we make up for in air flow. I personally would go with the Tail like many people have said numerous times becasue it will work very very well.

i run a procharger race blow off valve, so far i haven t turned up my boost to let the new motor break in, my friend runs the same blow off vavle on his f1 procharged motor at 22 lbs of boost with no problems, this blow off vavle is huge and i believe when i measured it before installing it the vavle itself is about 2 inch in daimeter, i have no surging problems with mine.

heres a link to a picture of mine if you scroll down you ll see it.

http://www.s10forum.com/forum/showthread.php?s=&threadid=57019&highlight=blow+and+off+and+valve

Just FYI, the DSM guys who run 10's use the stock BOV that is just crushed. They run huge turbos at 24+ psi on the stock BOV because it is a very good design, in fact the BOV is made by Greddy. Another thought is some one who has a stock WRX BOV, basically the same as a DSM with a little stiffer spring. My buddy who had one put a aftermarket BOV that was TurboXS and it leaked at 20 psi and stock doesn't leak, he has hit 23+ psi, on an 18g. In my mind both would do just fine as long as you kept it under 15 lbs.

Originally posted by Chris B
Are there any considerations from the inertia of the valve itself - it would seem if you go with a much larger valve then it will take longer for it to open - possibly leading to compressor surging, etc.?

Would it be reasonable to run one large valve and one small one, or what that be a waste (i.e. it isn't an issue?)


Chris

i believe that is how the HKS SSQ bov works. Dont quote me on it though

Just throwing an idea out, but what if you ran two of the DSM BOVs? Just curious to see if this will work. I know you can run multiple bypass valves on a supercharged system, I don't see why it wouldn't work w/ a turbo.

I'm wanting something quiet. If I wanted something to make a lot of noise on the street, I would've kept my Procharger. Stealth is the word here. :)

You could throw a map sensor in your intake tract and datalog it - that will let you know for sure if it is working.

Also, is it better to put the BOV close to the throttle body (where the pressure wave begins - air starts piling up), or next to the compressor (what I really care about and want to prevent an overpressure on)?

Thanks,
Chris