BOV ? (not sound or recirc vs. atmos.)

[lost888key]

I've read (500 threads for 'bov AND pressure' but I didn't count all the previous searches)

Here's the list of engine modds for the engine

-6 bolt block w/ 8.5:1 pistons
-port and polished head w/ 3 angle valve job
-2g manifold (for now, tubular equlength later)
-EVO III 16G
-GM MAF Translator (for rough tuning, probably use ECU+ for fine tuning)
-dejon IC piping and racing FMIC

here's my bov ?'s

What pressure is ______ bov capable of holding/venting effectively?
(with the exceptions of blitz and turbo xs, they advertize)


Which valves are best at controlling part throttle compressor surge?
(thinking a push/pull style like an HKS SSQV would best accomplish this)

Also, what kind of blow off valve and how was this tested? (on car, off car, and how readings were taken, and what readings were measured i.e. Using a Greddy type-s bov I pressurized the IC piping using shop air to 20 psi before the valve opened.)

last but not least, reliabiliity/rebuildability?

Thank you for your information, so I can make an informed decision based on actual data, instead of _____ bov is the loudest, so therefor the best.

If I can get a relatively complete list of bov's i will rewrite and submit the info in a tech article complete with references and thankyou's for all involved, after reading countless threads and finding lots "this one is the best" without a why, I'd like to be able to put back a "This is the one best suited to for this use, and here is why."

 

[Spoolin98]

The HKS Super Sequential Blow-Off Valve (SSQV) is a dual stage pull-type relief valve. Unlike typical push type blow-off valves, the SSQV will not leak under any level of boost because the boost pressure in chamber "C" keeps the valve closed against its seat (Diagram 1). The SSQV releases excess boost when there is a pressure alteration in chambers "A & B", not by the rate of boost pressure or vacuum in the line. This ensures a quick valve response and complete closure during idle. Many competitors use a push-type blow-off valve design with a large valve to accommodate high boost / high horsepower applications. These large valves react slowly and require high pressure to open, and are not able to activate and prevent compressor surge at light-load conditions. On the other hand, smaller, fast reacting push-type valves do not discharge the airflow capacity required for high horsepower applications and tend to slowly open and leak as boost pressure overpowers the spring. For maximum performance, the HKS SSQV incorporates both a small primary valve for ultra quick activation, and a larger secondary valve for additional discharge capacity. The SSQV is engineered to initially open the small primary valve at light throttle and load conditions (Diagram 2), then sequentially opens the secondary valve for additional relief capacity under high boost and load conditions (Diagram 3). The SSQV is constructed of polished billet aluminum, which ensures long-term durability and a high luster look. The mounting base utilizes a circular mounting flange that combines with a C-clip snap ring and O-ring gasket to insure an excellent seal. The triple-fin discharge port design produces a powerful, unique and aggressive blow-off sound.

 

[1998gst]

How much boost are you planning on running....street/track, pump/race gas, upgrading turbo later? I was pretty sure that the Type-S held over 20 unless you didn't have the spring that tight. I have heard that for high boost holding it's the tial. I am running the RS and it's a 40mm valve. The tial is a 50 I think. I wouldn't go anywhere near a XS because my past expiriences plus others is just that they are not that good at holding boost to well. I had the type-S and it worked fine for me I also had the SSQ but since I didn't have a recirc kit I took it off, but that thing held boost like a champ also. It's all in adjusting it to the right level. I had to replace the diaphram once in my type S and that took like 5 minutes. Again we need to also know what I wrote up top.... My opinion since your already running a translator/maft I would go tial if you plan on running high boost pretty much all day. Other wise I think the RS or a sequentil would be good also.

 

[1stGENracer]

I've got the HKS SSQV, I love it. It holds really good.

 

[TDX]

I went with the Greddy Type-S // Since im just starting out and HRC advised me not to vent for our engines.

 

[Sean485]

SSQV is nice because it can be recirculated, it is a dual stage valve so it works well even with smaller turbos but has a fairly large valve for bigger turbos and can hold back alot of boost without leaking out the valve early because of the pull design. It does have a couple downfalls though, one is that the flange is a poor design and difficult to install/remove the bov and it sometimes leaks under alot of pressure. The other "problem" with it that some people have complained of is that its ability to vent off enough air for cars running ALOT of boost (25+psi) fast enough is debatable and some people have complained of compressor surge between shifts because the bov just cant vent enough air (It can hold the pressure, just cant get rid of it fast enough) so they either have to switch to a bov designed to vent air faster (generally a tial) or if they wish to keep the lower throttle driveablilty of the dual stage valve or the "sleeper effect" of a recirculated bov that wont leak under insane boost levels they get 2 SSQV's so it can vent the air fast enough under full throttle shifts. IMO would be a very good bov for 90% of dsm'ers (and would be my personal choice if I wasn't a sadistic person with dreams of 30+psi )

The Tial bov can vent alot of air (50mm valve is huge) and it will hold all the boost you can throw at it so its perfect for if your running a larger turbo with alot of boost. But if you are running a smaller turbo it may have problems with compressor surge, you can get a softer spring for it to help with the problem but for most people this bov is very much overkill and since it cannot be recirculated it would require a VPC or maft setup as well which greatly adds to the cost.

The Greddy bov's are similar in design to the 1g bov and can be recirculated, the rs requires a kit which I belive is hard to come by at this time but the type S requires no kit to recirculate. They are also nice because they share the same flange, can be made to fit on a 1g bov flange with slight mods, are adjustable for keeping compressor surge at bay, and are fairly cheap. I dont know how well they flow when your running alot of boost but I would imagine they would start to have the same problem as the ssqv when you start running more boost or get a better flowing turbo as the outlet size on them is fairly small in relation to the tial. Again would be a good choice for 90% of dsm'ers who want an adjustable bov, the aftermarket bov noise when venting, or just plain dont trust the 1g bov

The 1g bov tends to leak at idle which makes it unsuitable for venting unless you crush it which sometimes causes compressor surge depending on the size of your turbo and how much you crush it. It is however extremly cheap (less than 20 bucks in a bone yard ussually) and is far better than the plastic 2g bov that leaks boost very badly. Again not real great for extreme boost levels as it may not vent off enough air and may start to leak at higher pressures but if your on a budget and aren't shooting for 11's the 1g bov should be more than enough.

 

[JessesTalon]

1g BOV can be good (crushed) up and past 20 psi...

I would choose a Tial or a HKS SSQV (I have had a HKS SSQV on every turbo car I have owned)

but if I was serious racer dude I would get a Tial.

 

[lost888key]

How much boost are you planning on running....street/track, pump/race gas, upgrading turbo later? I was pretty sure that the Type-S held over 20 unless you didn't have the spring that tight. I have heard that for high boost holding it's the tial. I am running the RS and it's a 40mm valve. The tial is a 50 I think. I wouldn't go anywhere near a XS because my past expiriences plus others is just that they are not that good at holding boost to well. I had the type-S and it worked fine for me I also had the SSQ but since I didn't have a recirc kit I took it off, but that thing held boost like a champ also. It's all in adjusting it to the right level. I had to replace the diaphram once in my type S and that took like 5 minutes. Again we need to also know what I wrote up top.... My opinion since your already running a translator/maft I would go tial if you plan on running high boost pretty much all day. Other wise I think the RS or a sequentil would be good also.

looking at the compressor map (TD05HR-16G6 this is the map for the 'EVO III 16G', right?), I'd have to say 10-15 psi street/ about 20 for solo 2, and as much as possible for drag ~25 (max for the turbo I think) . pump gas for street, add appropriate hardware store chemicals for racing. Clear up misinfo. I have a heap and a pile of parts sitting in FL (I'm currently in Phoenix, AZ) for the engine, the car does not run, the external parts are based off what I've read here and other DSM related sites, based on price and functionality. I'm making a price list, so that I can have the rest of the parts waiting for me when I get back I can spend a couple of weeks putting the car together and finaly drive it (see the rest of my posts for complete story)

Btw, 1998gst
Spoolin98
1stGENracer
JessesTalon
What kind of boost are you running?
Are the above numbers realistic? If not let me know, on a steep learning curve 1st turbo car.

I still want to write that article to help others who come along, give me data!!

Thanks to all

 

[TurboGuy702]

Id go with a SS BOV. I have it on my car and theres nothin like the sound.

 

[polarmoment]

an inexpensive alternative to the 1g BOV that will never leak and is of the same basic design as the HKS SSQ is the OEM toyota MR2 bov. it's also a pull-type valve that operates on pressure differential between the two ports (similar, but not the same as HKS) so it opens as soon as you start lifting and pressure in the manifold drops below pressure in the lower chamber. they typically cost about $30-40 from MR2 guys. i've got one on my car and i've yet to hear any surge at any boost level (below 20psi). when i lift off, it's open by the time i'm at 1/2 throttle, so it responds really quickly. the flange is a bit funky, but it can be modified to fit the 2g stock pipes for about $5 in parts from any hardware store. not sure about flow at higher boost rates, there aren't too many MR2's in the 25+psi range..

 

[96GSXawd]

hey everyone, i a sort of a newbie to these kind of things, but i was really looking to purchase the hks ssq bov for my 96 eclipse gsx and i have read alot about how to "not" vent into the atmosphere. so i was looking at buying a recirculating kit to go along with it. but what i was also wondering is if i would have to purchase the o-ring and the c-clip as well. any help would be greatly appreciated thanks

 

[Spoolin98]

hey everyone, i a sort of a newbie to these kind of things, but i was really looking to purchase the hks ssq bov for my 96 eclipse gsx and i have read alot about how to "not" vent into the atmosphere. so i was looking at buying a recirculating kit to go along with it. but what i was also wondering is if i would have to purchase the o-ring and the c-clip as well. any help would be greatly appreciated thanks

The oring and cclip come with the BOV, the recirculation kit comes seperately. I have an extra recirculation piece for the HKS, if you want it PM me.

 

[Scrymerr]

1g BOV or Tial.

 

[fwdturbobov1996]

new rs, tial , hks ssqv..

 

[I-luv-em-all]

The oring and cclip come with the BOV, the recirculation kit comes seperately. I have an extra recirculation piece for the HKS, if you want it PM me.

Hey, I was also wondering if you buy the HKS bov and the Recirculation kit, do you have to take out the stock "Benz" symbol insert in order to put the Recirculation piece in?

And if so, how does it sound when recirculated?

 

[EclipseRacing99]

the hks ssqv with the recirculation kit on it sounds kinda like a stock bov. it is quiet but you can kind of hear it.

 

[I-luv-em-all]

Well that kind of kills it. Everyone buys the HKS to get that patend "chirp"

A person may as well get the UICP MAF translator, so they can vent it. Or go with the Greddy or Tial.

 

[TDX]

Well that kind of kills it. Everyone buys the HKS to get that patend "chirp"

A person may as well get the UICP MAF translator, so they can vent it. Or go with the Greddy or Tial.

I personally like the Greddy Type-S chirp (kind of sounds like a lazer). Very cool but subtle.

 

[GPTourer]

Okay, I have a Type-S on my 2G, and have had it for four years, and I am thinking it is time to replace it or upgrade and need some ideas. I am having a problem with compressor surge, or I guess that is what it is called (engine races, turbo spools, but not going anywhere) in partial throttle in 1st gear. I almost have to be completely out of boost, or full throttle in first to keep it from happening. The rest of the gears are fine. My recirc pipe came off after I cleaned my filter a while back and the problem all but went away, and of course the BOV was hella loud. I didn't have any stalling problems, but I put it back of course to seal the intake.

Do I need to replace my Type-S with another Type-S? Or with a Type RS? OR with another brand of BOV all together. A 1g BOV, crushed or otherwise is out of the question. I run 20psi only.

 

[DarkSeraph]

go with the type-rs or the hks ssqv. Are you planning on recirc-ing or venting?

 

[GPTourer]

I will re-circ. Before I buy another one, I will try readjusting mine some more. I have never had the bottom nipple hooked up, so I will try running it to the J or L-pipe after the turbo. Am I correct in that this would be a boost source? The top one is on the intake mani and t'd with my MBC.

EDIT: NM, I just saw a post that showed a response from GReddy that says the bottom nipple should be left open.

 

[TurkF26]

well if no one noticed, he said hes running GM MAF so if he put that maf close to the intake mani\TB, id say go with Tial. He does not have to worry about recirculating because the MAF will be after the BOV. Go with Tial. Great price, and best of all you dont have to adjust it at all unlike the greddy, etc... just attach it and you are good to go.

 

[GPTourer]

well if no one noticed, he said hes running GM MAF.

Uhh, yeah - the original poster is. I have the stock 2G MAS.