Blitz DD/SS vs. HKS SSQV

[captain nismo]

Well the topic is pretty straight forward. I want to get either of them but I'm having trouble deciding between the two. Which BOV is better performance wise and sound wise? Also, Is the most common place to mount the BOV on the hotpipe? Can it go in other locations?ThanksChris

[forsaken]

I had kind of the same question. I wanted a good bov thats not too loud... not trying to attract cops in the least bit.

[vboyq]

from wat i gather on this site it seems the aggreeable place to mount a blowoff valve would be as close to the throttle body as possible, but there will be some that tell you on the hot pipe before turbo so i can't tell u for sure but im goin w/ the throttle body, when i finally get stuff started

[captain nismo]

what do you mean by "throttle body"

[SpeedRacer1]

Throttle plate = the piece of metal that lets air in? What are you confused about? You want to put it closer to the throttle plate so that the venting will be quicker and the vacuum hose will be shorter.

The reason why you see many BOV's on the hotpipe is because it is one of the only metal pieces on the stock intake piping. In reality it probably makes no difference. It is just a BOV, it doesnt matter which one you get, they both perform the same function. Neither will fail if tuned properly.

[robbbby]

I initally bought a blitz DD but now im going to trade it for a ssqv since it has a recirculation adapter.

[captain nismo]

Thanks speedracer 1. I know what the throttle body is i just didn't know about why you would want to put it as close as you can to it.

[vboyq]

u would put it close to the throttle body just so it can be realeased faster thats all, but like i said many put it near the hotpipe, like he said both will work just as good if tuned right

[themadscientist]

I put it close to the throttle because it will allow the air column to continue running through the intercooler. This has two advantages;

The intercooler won't heat soak waiting for the air to start moving again and,

You will only have to shut the BOV and fill 6" of pipe with an air column already moving full speed.

If you can a imagine a 10' length of hose flowing water with a dump valve at 2' and 8', imagine you vent the water at the 2' valve and then close it again. You now have to get 8' of water moving again befor it comes out the end, with the valve at the 8' point you only have to get 2' moving again with 8' of already moving water behind it.

[GraySilvia]

madscientist, I disagree on the BOV placement. If someone has a FMIC, the best place for the BOV is the hotpipe and i'll tell you why I think it is. If you place it on the hotpipe, and run as short a vacuum hose as possible to it, then it will be more effective at preventing compressor surge because the pressure signal will have a shorter distance to travel to open the BOV than it does to reach the BOV through the IC piping. Let's just say in round numbers that the pressure signal only has to travel 4' before it reaches the BOV, whilst it has to travel, say, 8' through the IC piping and the core to reach the BOV (the 'surge'). That means that the BOV will already be opening or opened by the time it reached the BOV. When you place it close to the throttle body, the distance the pressure signal travels to actuate the BOV and the actual surge travels is about the same, so it's less effective. That's just my $.02

[themadscientist]

blow off open by a vacuum signal from the intake, not a pressure signal from the turbo. With this in mind your signal hose would be shorter not longer by being placed closer to the throttle body.

[Cyberkreig]

by blowing off from the hot pipe, wouldnt you be venting hot moving air (turbo is still spinning), while the air in the IC simply sits and cools (you are still moving).. So you vent hot air and chill the intake charge for when you get back on the throttle. seems win win to me.

[themadscientist]

if you have ever felt the hot side of the intercooler you know it's hot. The air inside needs to move across the core to cool, if it is just sitting there your not using the maximum potential of it's cooling ability.

[GraySilvia]

blow off open by a vacuum signal from the intake, not a pressure signal from the turbo. With this in mind your signal hose would be shorter not longer by being placed closer to the throttle body.

I know, but it's a pressure signal nonetheless. And since you cut out that long distance that the actual pressure signal travels through the circuitous intercooler plubing, the BOV receives the signal first. The actual shockwave has to travel all the way through the cold pipe, down through the intercooler, and back up to the hotpipe, meanwhile the BOV has already received the vacuum signal from the intake plenum.

[Cyberkreig]

TMS, but what i'm saying is if the car is moving forward, and you are venting the heated air, no new heat energy is entering the core.. this should cool the core all the way across.

[themadscientist]

not really. you are venting the air before the intercooler, the air between the blowoff and throttle will be stagnant and will impart it's heat to the intercooler. Air flowing through the outside will go to work cooling the air trapped in the system but without it moving it will not do it as well as if the air was moving through the system. It will only work towards cooling the air that is trapped in the intercooler, the air in the rest of the pipe tract will just sit and impart it's heat to the entire system. Also any piping in the engine bay will heat up the stagnant air in them.

[hokiruu]

Very interesting discussion. One less cooling related factor is that- should you get the HKS BOV, mounting it on the hot pipe makes it easier to recirculate the air. Imagine trying to plumb hose all the way from the throttle body, back into the intake to recirculate. I am personally in the throes of trying to decide how to manage comprssor surge. I.E. recirculate vs. vent to atmostphere, which brands of valves, where to mount, etc. A bit off topic but has anyone had any experience with the HKS bypass valves? I am considering one of those or a TurboXS bypass valve.

[GraySilvia]

not really. you are venting the air before the intercooler, the air between the blowoff and throttle will be stagnant and will impart it's heat to the intercooler. Air flowing through the outside will go to work cooling the air trapped in the system but without it moving it will not do it as well as if the air was moving through the system. It will only work towards cooling the air that is trapped in the intercooler, the air in the rest of the pipe tract will just sit and impart it's heat to the entire system. Also any piping in the engine bay will heat up the stagnant air in them.

Now that's just silly. If you have a pressurized intake, and the BOV opens, you're DEPRESSURIZING it, which means the air inside will cool. The air trapped before the intercooler will cool down, but still be above ambient temperature, since the compressor didn't compress it 100% efficiently. The air that has been cooled by the intercooler, however, will cool down to BELOW ambient, since it's compressed, and it's temperature dropped because of the intercooler. Then you take the pressure off of it, and, voila, a great COOLING effect on the IC piping after the intercooler. So you would actually be chilling the piping a little, but this effect is pretty much negligible anyway, since the time it takes to shift and the time the air is stagnant is very small.

[xxjordan88]

The bov is placed close to the throttle body on the turbo eclipse, mitsu must have done that for a reason.

[SpeedRacer1]

Well Nissan placed the recirc valve on the Silvia about 5 feet of piping away from the TB, there must have been a reason for that (or not).

[bob marley]

Couldn't you mount 2 bovs? I used to be really into supras and I remember quite a few people using 2 aftermarket bovs. Some even used the stock one and aftermarket one.

Johann

[hokiruu]

Couldn't you mount 2 bovs? I used to be really into supras and I remember quite a few people using 2 aftermarket bovs. Some even used the stock one and aftermarket one.

Johann

WHY?

[SpeedRacer1]

Extra venting, people with 2jz-gte's and rb26dett's do it, in other words inline 6's.

[Cyberkreig]

TT's running BIG boost.

[hokiruu]

Sorry to jack the thread a bit more, but I am looking at a few valves and can't decide. 2 of them are the ones metioned in this thread, but I am also interested in Greddy Type S, TurboXS Type H, and most interested in Go Fast Bits Stealth FX or Hybrid units. One thing I am trying to figure out is mounting them to the stock s14 hotpipe. Somewhat relevant to this thread: except for the HKS (50,60,65mm flanges available), all of the other companies flanges are flat, not particularly useful for mounting on my 50mm hotpipe. That combined with the option to recirculate chalk it up two points over the Blitz.

[bob marley]

I just thought the 2 bov thing was interesting, sorry. I figured it was because of the high boost, but wasn't sure.

Anyways, what other BOVs have the option to recirculate?

Johann

[hokiruu]

Anyways, what other BOVs have the option to recirculate?

Johann

Besides the HKS, the Greddy Type S is pretty easy to recirculate I guess. I think I will end up getting that one. check out http://www.blowoffvalves.com and go to the supra sound clips, they have a sound clip of the Type S on a high boosting supra with a T03 and it sounds SO sick! Cool enough to almost make me consider not recirculating it.

[Und3rprshUr]

Blitz dd sounds sick

[hokiruu]

Blitz dd sounds sick

Yeah, it has a sound all of its own. More of a "SSsshhhhh" than any fancy little whistles or rings, at least with the SUS mini filter attatched. However- no recirculation option=not getting it.

[robbbby]

Very interesting discussion. One less cooling related factor is that- should you get the HKS BOV, mounting it on the hot pipe makes it easier to recirculate the air. Imagine trying to plumb hose all the way from the throttle body, back into the intake to recirculate. I am personally in the throes of trying to decide how to manage comprssor surge. I.E. recirculate vs. vent to atmostphere, which brands of valves, where to mount, etc. A bit off topic but has anyone had any experience with the HKS bypass valves? I am considering one of those or a TurboXS bypass valve.

This is also what I have been trying to figure out. I am going with the HKS SSQV with a recirculating adapter. I don't know if it would be better to mount it on the hotpipe and have a nice short recirculation hose or mount it on the cold pipe and run a hose all the way across back to the intake.