Difference btwn putting BOV on cold or hot pipe?

Sketchy564

Sketchy564

Driver
I went ahead and bought a cold pipe with a greddy flange for my BOV. I was looking around enjuku this morning and i noticed, they sell the hot pipes with the BOV flange on them, and the cold pipes with no flanges

However ive seen SR setups with the BOV on the Cold side, so i dont think its a big deal

So i was just wondering, is there any difference between locating your BOV on one side as opposed to the other?
 
Sketchy564 said:
I went ahead and bought a cold pipe with a greddy flange for my BOV. I was looking around enjuku this morning and i noticed, they sell the hot pipes with the BOV flange on them, and the cold pipes with no flanges

However ive seen SR setups with the BOV on the Cold side, so i dont think its a big deal

So i was just wondering, is there any difference between locating your BOV on one side as opposed to the other?
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The point of a blow off valve is to release the air built up in the charge pipes when the throttle body closes. The air is vented because if its not its been argued that the air will bounce off the closed throttle body then back into the turbo which in terms of air pressure could possibly cavitate the turbo which could in return destroy seals, bearing, etc.

So its always made the most sense to me to have my B.O.V on the cold pipe, so that as soon as the Throttle Body closes the point of escape is closer to the point of rebound, and it allows for all new fresh chilled air to come back into the charge system when you mash the throttle again.

But thats just my theory. Others argue its better on the hot pipe.
 
Sweet, thats exactly the kind of info i needed

And that makes perfect sense as well, so now what im wondering is why one would argue it being better on the hot pipe?
 
i think the reason ppl put them on the hot pipe from what i heard they say its louder! but to me it sounds the same
 
i heard it's supposed to be closer to the turbo (hot pipe). so that the pressure near the turbo is lowered quickest.

but i really dont think it makes a difference tho
 
The argument for the hotpipe is normally because it is easier to recirculate. This is common on ka's because most people recirc the BOV to combat stalls when they let off the gas (throttle plate closes, bov dumps excess air, less metered air enters engine, engine floods and stalls). It is often easier to recirc the bov than it is to tune the computer.
 
benarovi said:
weld it on the rims then
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Do i need 4 BOV's or can i just use one on all 4?

N4kedSquirrel said:
The argument for the hotpipe is normally because it is easier to recirculate. This is common on ka's because most people recirc the BOV to combat stalls when they let off the gas (throttle plate closes, bov dumps excess air, less metered air enters engine, engine floods and stalls). It is often easier to recirc the bov than it is to tune the computer.
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Hm... trying to comprehend how all that works. What do you mean by "less metered air"? And why would the engine flood and stall from this?
 
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Sketchy564 said:
Do i need 4 BOV's or can i just use one on all 4?




Hm... trying to comprehend how all that works. What do you mean by "less metered air"? And why would the engine flood and stall from this?
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Boosted air is metered by the maf. When you blow off air into the atmosphere you are venting air thats been measured by the maf, thus the engine thinks there is more air then there really is and puts too much gas. If you recirc the blow off air this will not happen.
 
i always thought closest to TB....but after talking to this guy thats been doing crazy engine shit for over 10 years..he said its better to do it on the hot side because of it letting out more hot air instead of cold air which the hotter the air more pressure loss your going to have which in the end is less power. im running mine about 8 inches from the compressor housing
 
JiujitsuDrift said:
Boosted air is metered by the maf. When you blow off air into the atmosphere you are venting air thats been measured by the maf, thus the engine thinks there is more air then there really is and puts too much gas. If you recirc the blow off air this will not happen.
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Alright after reading that a few times that makes sense. But if thats the case why do so many people run regular, non-recirculating blow off valves? Or is there somthing im missing that i should know
 
Sketchy564 said:
Alright after reading that a few times that makes sense. But if thats the case why do so many people run regular, non-recirculating blow off valves? Or is there somthing im missing that i should know
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because it sounds cool, and they want everyone to know they have a turbo. the HKS super sequential makes a special insert that makes more noise o_O

in all honesty, most people that have BOVs dont even beed them. they arent making anywhere near enough power or using it enough to warrant the purchase.

to answer your question from what I know...its a subject of better throttle response/performance (cold) vs. turbo life/upkeep (hot)

dump it from the cold side and the pipes stay somewhat charged, and will take that massive huge ass front mount you bought to fill up again with air. or dump from the hot and put less stress on your turbo.
 
kwkouki said:
because it sounds cool, and they want everyone to know they have a turbo. the HKS super sequential makes a special insert that makes more noise o_O

in all honesty, most people that have BOVs dont even beed them. they arent making anywhere near enough power or using it enough to warrant the purchase.

to answer your question from what I know...its a subject of better throttle response/performance (cold) vs. turbo life/upkeep (hot)

dump it from the cold side and the pipes stay somewhat charged, and will take that massive huge ass front mount you bought to fill up again with air. or dump from the hot and put less stress on your turbo.
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Well im not gonna lie, part of the fun of a turbo car is getting to hear wshhhhhhhhh tss-s-s-s every day :D

But why would it not be necessary? Even if your not making a ton of power, wouldnt it still be a lot healthier for your turbo than no BOV?

What makes it so that the pipes stay somewhat charged and give you better response if your dumping it from the cold side as opposed to the hot side? Either way, wouldnt the side without the BOV still have some air in it?

Also what makes it put less stress on the turbo having it on the hot side? If drumfunkens theory is correct (which it makes perfect sense), then wouldnt the rebounding air exit almost instantaniously with it on the cold side?

Lastly if it makes a difference, my front mount really isnt that big compared to the monster ones i see people running all the time. Never really thought of this as an issue, but now the more i think of it im guessing the larger the intercooler the longer it will take to spool the turbo?
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thank you to everyone answering my questions and helping me out. Just trying to learn lol
 
DrumFunKen said:
The point of a blow off valve is to release the air built up in the charge pipes when the throttle body closes. The air is vented because if its not its been argued that the air will bounce off the closed throttle body then back into the turbo which in terms of air pressure could possibly cavitate the turbo which could in return destroy seals, bearing, etc.

So its always made the most sense to me to have my B.O.V on the cold pipe, so that as soon as the Throttle Body closes the point of escape is closer to the point of rebound, and it allows for all new fresh chilled air to come back into the charge system when you mash the throttle again.

But thats just my theory. Others argue its better on the hot pipe.
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+1000000 on cold pipe its closer to the throttle body and far from the turbo 2 wins - 0 loss
 
Garrett Recommends the BOV to be mounted close to the turbo.

"MAF (Mass Air Flow) sensor uses a recirculation (bypass) valve for best drivability.
* Connect signal line to manifold source
* Position valve close to the turbo outlet for best performance (if valve can handle high temp).
* Surge can occur if valve and/or outlet plumbing are restrictive."

Taken from there "Turbo Optimization" article in the turbo tech section on there web page. I would trust what they recommend as the best option.
 
techincally it should be the hot side and recirculated into infront of the turbo.

there is no point in dumping cold air.
Recirculation should have the shortest distance to travel
You will get less afterfire if dumped on the hotside
 
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