Dual BOV set up.

[JamiesTSI]

I would like to run a dual Super Sequential set-up on a three inch upper intercooler pipe.

Am I correct in saying that the HKS Super Sequential is only rated for around four hundred horse?

I would like to know if anybody has done this. How they placed the BOV's on the pipe. Did they run one vaccum line then tee off to the other BOV.

Basiclly the whole ball of wax to make this happen the most efficent way possible.

Thanks,

Jamie

 

[Prodigy]

One hks Bov is rated at 550whp

 

[Mirage2LTurbo]

How do you rate a BOV for horsepower? It doesn't care about that, all it see's is boost and vacuum. They are rated at a certain boost level.

 

[kpt4321]

Perhaps they are getting this horsepower rating based on the maximum airflow that can pass through the BOV at a given pressure ratio?

That brings up an interesting point, in that at a given horsepower level you may need more BOV on a larger engine, since it's operating at a lower PR.\

 

[Mirage2LTurbo]

Perhaps they are getting this horsepower rating based on the maximum airflow that can pass through the BOV at a given pressure ratio?

That brings up an interesting point, in that at a given horsepower level you may need more BOV on a larger engine, since it's operating at a lower PR.\

Possibly true, but if you went to larger piping, the PR would be the same at an increased flow level. The BOV doesn't respond to flow, it responds to pressure and vacuum.

 

[Mirage2LTurbo]

I would like to run a dual Super Sequential set-up on a three inch upper intercooler pipe.

Am I correct in saying that the HKS Super Sequential is only rated for around four hundred horse?

I would like to know if anybody has done this. How they placed the BOV's on the pipe. Did they run one vaccum line then tee off to the other BOV.

Basiclly the whole ball of wax to make this happen the most efficent way possible.

Thanks,

Jamie

Back to your post, just weld two BOV's on and run a vacuum line to each. If you wanted to get fancy, you could put either an inline reducer or just run an extra long vacuum hose and attempt to offset the second BOV opening Not sure exactly how well that would work, sounds good in theory.

 

[Eclipsei95cl]

I always wondered what is the point to run 2 Blow off vavles??? Besides that its differnt and will let off 2 wooshes instead of one..I really dont see the point to run 2 of em performance wise.

 

[thekellbeast]

Let's say that you're building a 1k hp Supra. If you have a tiny BOV, when you shift, the BOV is going to have trouble squeezing all that air that's built up, out. You're still going to have air/pressure in the charge pipes, which will affect the turbo. The solution? Two BOV's. That way you can let more air out of the pipes. That being said, it would take quite a bit to exceed the capabilities of one BOV.

 

[Kevin Jewer]

More so than HP, I think it has to do with turbo size. With a very large turbo, you have a lot of inertia that wants to keep it spinning. Add to that how much air large turbos move at low shaft speeds, and you have a lot of air to get rid of. Larger turbos (relative to engine displacement) also lag more, generally speaking, so you need to do everything in your pwer to keep the turbo from slowing down on a shift. A larger BOV will alow more air to escape faster with less resistance so the turbo will not slow down as much. I know Leon didnt finally upgrade from the 1g BOV (to a Tial) until he was running a stage 5 turbine wheel turbo (60-1?) that lagged a lot. In my case, the GT67 takes forever to respool if I lift off the throttle to shift. Just falls flat on its face. Extremely low vacuum and placing the BOV before the FMIC are not helping at all either In extreme cases 2 BOVs can be beneficial I'm sure.

At any rate, I wouldnt rate a BOV by HP. Same for wastegates. I will never understand why manufactures/vendors try to do this...

 

[pianoman]

instead of running two, why not just run one with a bigger valve like the tial? its cheaper then buying two hks' anyhow.

 

[greathuskie]

i would personally rather run 2 for a few reasons, one because no one else does it for DSMs so it would be different, two it would work just as good as running a single larger one, three it would sound badass

 

[GSX_RCR]

i would personally rather run 2 for a few reasons, one because no one else does it for DSMs so it would be different, two it would work just as good as running a single larger one, three it would sound badass

Obviously you just missed the entire post by 95GSXracer.

At any rate, I wouldnt rate a BOV by HP. Same for wastegates. I will never understand why manufactures/vendors try to do this...

That's because HORSEPOWER sells...not psi/pressure ratio/etc etc.

 

[tsi4ya]

does anyone know how much the Greddy(purple) BOV is rated at . .am nor sure and please correct me if am wrong but i read off some where it was good till 20-23?

 

[boost05]

well I Can tell ya right now it will be nice and loud, the first one may flutter and the second one may whisle thats what my friends does on his supra he has 2 ssq's

 

[bastarddsm]

ya, but that supra is movind much more air like 33% more air so I doubt it would work the same. there are probably only a few dsm's in the world that need 2 bov's if any, and those are the cars taht are making 900+ hp so unless your making that much power it is a waste of time and money.......

on a random side note i didn't have a bov in my car it was blocked off. it went 13.3 at 108 mph on a stock n/t exhaust (except for the DP)/ clutch/ motor/ and street tires at 11psi, so i really don't think bov's are that important

 

[KPWSerpiente]

so i really don't think bov's are that important

Congrats. Too bad what you think is wrong. I hope when your shaft wobbles more than John Kerry (badddup bissh!) you change your mind.

-T

 

[JessesTalon]

Technically a BOV does nothing to your power during 1 gear acceleration.... for example... 3rd gear wot from 2,000 to 7000....

but if you want your turbo to last past 50k... then you will need a BOV to protect your turbo from premature wear.

 

[Kevin Doe]

Let me set this straight.

BOVs only care about a few things.
1. Pressure in the system (Boost Pressure - absolute)
2. Pressure outside the system (Atmos Pressure - absolute)
3. System Volume (usually comprised of IC piping, and intercooler)
4. Area of discharge (area of vent port)
5. Coffecient of Discharge (determined by geometry of vent port)

One and two are important because they dictate the pressure ratio of the system, which drives the air out. Air flows from high pressure to low pressure.

Three is important because that is what dictates how much air needs to be evacuated from the system.

Four and five are important because they dictate how much air can exit through the BOV at a given pressure ratio.

Horsepower is irrevalant. The larger the pressurized volume, the more air that needs to be ecacuated. Same goes with boost pressure, the higher boost, the more air that needs to be evacuated. IF, you cannot quickly enough vent enough air to prevent surge/stall, you need a bigger area valve. OR, two valves.

Kevin

 

[Prodigy]

Lets take the Mk4 Supra, After you go past Bpu must supra owners go with Two hks bovs or one racing type. After you past bpu on a supra 550whp is not much of a problem and very well the limit of the hks bov. Yes it does have something to do with Air flow being that the one hks bov can not support the amount of air. But still i would not see a reason for two bov's on a dsm unless like said above you are making well over 600hp. Then u could get one racing type...Also at Bpu on must mk4 they keep there stock bov and then put a hks or blitz which i never really understand unless it has something to do with stalling????

 

[bastarddsm]

there are tons of factory turbo cars that didn't come equiped with a BOV from the factory. all the ford turbo cars ( SVO XR4Ti Turbo Coupe), Dodge turbo cars (Laser, Shadow, Daytona, Shelby), Buick GN's, I think Syclone, and Typhoons don't either and thier turbos last.

 

[greathuskie]

there are tons of factory turbo cars that didn't come equiped with a BOV from the factory. all the ford turbo cars ( SVO XR4Ti Turbo Coupe), Dodge turbo cars (Laser, Shadow, Daytona, Shelby), Buick GN's, I think Syclone, and Typhoons don't either and thier turbos last.

ever heard of cutting costs? by the time there is a problem with the turbo on any of those cars they would be out of warranty, so its no longer the dealers problem until they get paid to fix the car

 

[IMMORTALSPYDER]

there are tons of factory turbo cars that didn't come equiped with a BOV from the factory. all the ford turbo cars ( SVO XR4Ti Turbo Coupe), Dodge turbo cars (Laser, Shadow, Daytona, Shelby), Buick GN's, I think Syclone, and Typhoons don't either and thier turbos last.

My 93 Scoupe turbo didn't have a bov or intercooler stock

 

[Kevin Jewer]

You cant say that a BOV cant handle a certain airflow. Air doesnt go through it when you are making power. Most of the cars that dont use BOVs run low boost, and in some of the examples given, low boost on high displacement motors. You dont always need one in that case. Try 25 psi with no BOV though. Ever heard it? A bunch of the RWD 2sp auto DSMs dont bother with a BOV since you dont lift to shift. But for 99.9% of the poeple on this board, a BOV is entirely necessary.

I'll say it again. It has nothing to do with HP. It has to do with how much your particular setup lags. One way to reduce lag is to be sure you are venting all excess pressure from the IC pipes with as little restriction as possible so the compressor freewheels during shifts. Less re-spooling to do. Just because this happens to be an issue on high HP cars (since they tend to run laggy turbos ) doesnt mean its HP related. But I can see where the confusion comes in.

 

[guitarXgeek]

there are tons of factory turbo cars that didn't come equiped with a BOV from the factory. all the ford turbo cars ( SVO XR4Ti Turbo Coupe), Dodge turbo cars (Laser, Shadow, Daytona, Shelby), Buick GN's, I think Syclone, and Typhoons don't either and thier turbos last.

Just because it came from the factory that way doesn't mean it's right. 2g dsm's come from the factory with a defective crank (yea, I said it ) but that doesn't make it right!

 

[JamiesTSI]

Boy thats alot of info to digest. Thanks for all the replys.

What I have(pertaining to the BOV's) is the BR57, Buschur front mount, 3 inch upper intercooler pipe, 3 inch throttle body, and a BJ's intake.

My thoughts where at 35 pounds of boost is that one BOV going to bypass enough air out before it slams shut. Hench the idea lets get on Ebay and pick up a second BOV.

Also 95GSXracer had some good points.