Where would you put your BOV?

[NemeGuero]

Ok, so the dealio is I've heard various things about the best location for a BOV. Basically I'll break it down into:

1. on the cold pipe just before the TB
and

2. immediately after the compressor on the charged pipe

1 gives the best throttle response (or so I've heard) but blows off quite frequently

and 2 is best for turbo life and easiest in the event of recirculation.

So I ask upon you, my fellow zilvians, to give me your input/opinions/rude comments/flame/jealousy/newbish stupidity or any of the other things that makes zilvia great...

Also, please consider this is a MAFS setup.. not MAP. If you don't understand why that matters.. ignore it. ;)

You may proceed.
<3 Nemo.

[SoSideways]

I will let you know how often the BOV opens once I relocate mine to the elbow right after the FMIC.

Loud and annoying coming right up!!

<3 Neme

[NemeGuero]

All these opinions without explanations? hmm...

[EchoOfSilence]

throttle responsssssse and recirc it. haha!

[Sil-Abc]

what is this... BOV?

[g6civcx]

Cold pipe, convert to MAP, and vent to atmosphere.

[NemeGuero]

Wish I could afford to convert to MAP.

[TAMTANIUM]

If it was my decision to put a bov on my car...
It would be on the cold pipe right after the throttle plate.
You will get a nicer response from the bov.
My friend put his bov there and it's a little better response.
Compare to my bov on the hot pipe, it's like whatever. By mean
sucky bov response...that i can still hear my waste gate.

[EJ253]

cold pipe. recirc it.

[SoSideways]

So everyone who posted in the thread supported all the votes for the BOV being on the cold pipe right by the throttle body, but where are all those people who suggested the BOV be placed on the hot pipe? Where are their explanations as to why they chose that side?

[smelly240]

i figure closest you can get it to the throttle body the better. The pressure in the pipe is jacked up because the throttle plate closed - so i imagine the pressure begins to increase there first, - plus it should be more responsive there - due to it having the earliest and largest pressure difference

supra guys have those super long TB's they weld a flange right to em - where the traction flapper thing is.

[drift freaq]

well for recirculation factor mine is on the hot pipe by the compressor. Why because RB's do not run for shit vented to the atmosphere. I also happen to believe in recirculating the blowoff to cut down on the amount of crap my car could possibly be putting out into the air. Thats me and some of you wil just why does it matter man. Well if you even have to ask that question you need to take a look at the world around you. hahahhahha.

[yfz460]

Screw putting it on the piping... put it right on the intake manifold! :aw:

LoL.... but seriously, I say put it on the cold pipe, better throttle response is a must (imo...) for a turbo'd car on the street or track, especially if you're running a larger, laggier setup.

[drift freaq]

Screw putting it on the piping... put it right on the intake manifold! :aw:

LoL.... but seriously, I say put it on the cold pipe, better throttle response is a must (imo...) for a turbo'd car on the street or track, especially if you're running a larger, laggier setup.
Throttle response? hehehehhe With RB and HKS GT2535 we don't need to worry about no stinkin throttle response. hahhahahhahhahhahha

[yfz460]

Not all of us are so fortunate to be able to afford a beautifull piece of Japanese engineering freaq...

Oh, and I ran my BOV on my deceased car on my hotpipe vented to the atmosphere. It was the new version of the HKS SSQV (no adjustment on the back, and was authentic) and I had no problems with it stalling but it would sometimes go down to about a 100-200rpm idle for a second or two after pushing the engine.

[NemeGuero]

I'm using the new SSQV too.. Courtesy of Ernest! (SoSideways)
But it seems mine will be on the cold pipe.. and quite possible have a huge tube going across the bay for recircing..

[yfz460]

I'm not 100% sure how well it works, or how it works, but HKS makes (or made) a unit called the EIDS (electronic idle stabilizer) to aid in the idling of atmospheric bov systems on MAF cars. HKS claims it "buffers" signals from it which it could possibly do, I'm no electronic genius like those crazy HKS guys so I have no input on that one.:loco:

http://www.hksusa.com/products/?id=2175

^^ Info on the unit.

[NemeGuero]

Hmm.. cool link. Anyone tried these or have any more info on them?

[punxva]

u could also use an SAFC and use the decel air setting :)

[S14DB]

Or just trash the BunkiROM and get an AEM EMS and convert to IAT+MAP.

But really there is a reason the s14SR moved the BOV to were it did. The Pressure wave that causes compressor surge starts at the TB. Most of the charged air is in the IC. Dumping it in the hot pipe causes the air to back flow. 1, loosing response and 2, the possibility of BOV induced surge.

Cold pipe is the only was to go.

[NemeGuero]

Yay, finally some factual evidence to base opinions off of.
Thanks AJ.

And If you'd sell me your EMS for $500.. I'd do it. HAHA

[S14DB]

Sold it a month ago and my Power FC is on it's way.

[SoSideways]

Yeah my friend Brian who was stationed over in Japan for a long time and said he built a lot of S-chassis, also said something along the lines of what S14DB said.

Basically he said that the charged air is in the IC and cold pipe when you close the throttle plate, so it would make sense to put the BOV there to vent the air there to prevent it from going back into the compressor, where the initial compressed air from the compressor is still making its way out of the compressor outlet to the IC and cold pipe side.

[NemeGuero]

cool. So I guess that's where I'm putting it..

Recirc will depend on what my AFRs look like..

[g6civcx]

The S13 puts the compress bypass valve on the cold pipe of the sidemount. You can see it capped off below.

I moved it into the engine bay to keep it clean and for easier recirculating. Look how dirty the sidemount is.

The S14 moves it even further up the coldpipe. I think that's the right thing to do. Just make sure you route your hoses correctly.

http://g6civcx.angryhosting.com/S13/Tech/SMIC3.JPG


Oh, and the pink slippers are not mine. I swear! :) :)

[SoSideways]

You know, now that you've brought that up g6civcx, the Skyline GT-Rs also have their recirc valves on the cold pipe, right in front of where the JDM driver's side front wheel is.

So it's settled, for performance's sake, BOVs should go on the cold pipe, as close to the TB as you can get it (although I've heard 6" from TB is the best spot for it?)

[NemeGuero]

Well I'll give it a few inches for hood clearance issues..

[blu808]

Evan. Unless you are making hella hp, i would put it on the hot pipe. I would put it there because on a lower cfm car it is better to release the pressure before the intercooler, that way the ic can keep some pressure in it.


You dont want to drain all the pressure in your fmic then have to refill it before you feel the boost kick in. Yes i know even on the hot pipe it will drain the fmic, but not as bad as on the cold side.



Like my sig \/ haha

[Wykydtron]

Just to let everybody know, Wastegates make a PSSSHH noise too! >=D

[Neejay]

The S13 puts the compress bypass valve on the cold pipe of the sidemount. You can see it capped off below.

I moved it into the engine bay to keep it clean and for easier recirculating. Look how dirty the sidemount is.

The S14 moves it even further up the coldpipe. I think that's the right thing to do. Just make sure you route your hoses correctly.

....


Oh, and the pink slippers are not mine. I swear! :) :)
That is a very good point. I'd never thought about or noticed that. Would this also apply to a aftermarket fmic? Because blu808 brings up a valid point as well...

PS: Those flip-flops/slippers are yours and you know it!

[g6civcx]

Luke's point is that you don't lose as much pressure across the intercooler if you're running low boost. If you vent at the coldpipe, the intercooler loses pressure more quickly because air goes through the intercooler and out the BOV. When you start boosting again, it takes time to fully pressurize the IC.

If you vent at the hotpipe, you will lose less pressure across the IC because air is less likely to go backward across the IC to the hotpipe. When you start boosting again, the IC will still be charged slightly, leading to better throttle response.


What I've noticed is that with a huge FMIC and a tiny T25, the T25 feels laggier and runs out of breath more quickly than the SMIC. It's not until you get to higher speeds where the FMIC's superior cooling starts paying off.

[NemeGuero]

t3/t4 .50 trim .63a/r... 8psi
starion conquest FMIC (fairly small)
2.5" IC piping.. what do you think?

[Neejay]

Luke's point is that you don't lose as much pressure across the intercooler if you're running low boost. If you vent at the coldpipe, the intercooler loses pressure more quickly because air goes through the intercooler and out the BOV. When you start boosting again, it takes time to fully pressurize the IC.

If you vent at the hotpipe, you will lose less pressure across the IC because air is less likely to go backward across the IC to the hotpipe. When you start boosting again, the IC will still be charged slightly, leading to better throttle response.


What I've noticed is that with a huge FMIC and a tiny T25, the T25 feels laggier and runs out of breath more quickly than the SMIC. It's not until you get to higher speeds where the FMIC's superiorior cooling starts paying off.
So: Low boost = you could get away with oem bpv (smic) or hotpipe. Higher boost (12psi+?) = recommended coldpipe and fmic?

[g6civcx]

So: Low boost = you could get away with oem bpv (smic) or hotpipe. Higher boost (12psi+?) = recommended coldpipe and fmic?

I really have no preference on the actual location of the BOV itself. I just prefer to put it wherever convenient, clean, and easy to get to.

Ask Luke if you want to get nitty gritty.

As far as ICs go, I would NOT be comfortable going into the teens with a sidemount. I don't think the tiny little sidemount can handle that much boost.

[SoSideways]

Well I have the Greddy V-SPL and plan on going with an S15 T28 or even the GT2871R, and am after throttle response.

What's recommended in that sense?

Right now I have the BOV on the hotpipe, T25 @ 10psi (was 14psi but it's getting cooler out, backed off the boost just in case it spikes), and so far the boost response isn't that bad...

[DJ_Sunrise]

ive heard from tons of people that cold pipe is ideal.. and when u look at many race cars that are turbo'd, there it is again on the cold pipe.. for instant response, go with a Tomei Expreme exhaust manifold. the response with this exhaust manifold is absolutely amazing.. oh.. btw.. s14 sr, blitz fmic, stock t28, mr dp, mr outlet, 2.5 cat delete 80mm apexi dual. equal length makes more power, tomei expreme ass load of response.. i build 1.1 lbs. cranking the engine...

-Bart

[SoSideways]

^^ Is your boost gauge accurate?

I mean... all the gauges usually are not in fully operational state when you first crank your car.

[NemeGuero]

Fucck..

Response? Or keep boost pressure?

[midnight zenki]

Based off of what Luke stated you can also view hot side mounting like this; when the pressure is relieved at the compressor the purge is only monentary and then the throttle is opened again to whatever degree is desired, this means that the compressor is still spinning and will be right there to push the remaining charged air that was sitting in the cold pipe and IC during release straight back into the plenum without any gap to be filled inbetween the throttle plate and IC. What I am trying to illustrate with words is that the air will be left right at the throttle when the air is purged at the compressor. To me this would seem to provide a quicker response in theory.

[SoSideways]

If you have a ball bearing turbo then boost response is gonna be pretty amazing no matter where you put the BOV man :)

Just put it on the intercooler like WRC teams do lol Right dab smack in the middle, nothing to worry about :bigok:

[NemeGuero]

You got one for me, Ernest? I'll give you $8 for it. haha

[SoSideways]

You got one for me, Ernest? I'll give you $8 for it. haha

That might cover the shipping :)

[sean350z]

stock evo mr bov on cold pipe recirculated for s15 SR stock boost and sometimes 12psi. works wonders and engine runs as smooth as a babies bum and it cost me 15 bucks :)

had a ssqv and that shit made compressor surge and was vented to the atmosphere...made my engine run like crap <- $200 bovs are overrated imo

EVO MR bov FTW!!!

[NemeGuero]

Well its on the cold pipe. I couldn't resist.
I like it.. alot.
No stall on decell.. no complete richness coming up to a stop light..
hella more predictable and the car just runs soo much more smoothely..
Still a few issues.. but at least I'm making progress!

[EchoOfSilence]

pictures, bitch!

[NemeGuero]

http://img167.imageshack.us/img167/9692/1118061619avc0.jpg
http://img84.imageshack.us/img84/271/1118061618du8.jpg
http://img168.imageshack.us/img168/9458/1118061619ha3.jpg

Excuse the dirty engine bay please...

[smelly240]

if its there you wont get as much compressor surging (at least on my car it went away - but i also changed to a tial BOV. the old bov wasnt opening long enough - it was like chhuuuuurgupbooop boooop boooop booop boop boo. now its just pshoooooooootuh boop. i have a holset. and teh best sound - is with no bov (booooop booop boop boop boooo :D) but im told my turbo will get beat up - not that i care that much tho.

[blu808]

Told you would be happy with the hks.


Woot. good goin man.

[NemeGuero]

Yah man, thanks for the recommendation. I still am having some electrical related issues though.. I'm gonna try swapping my MAFS with someone elses, gonna try to throw back in the 370s.. and a few other things like a grounding kit and such.

[blu808]

I would consider hitting your maf with some brake cleaner before you swap it out.


Also remember how your car had a grounding problem. That could cause it too. try replacing the main ground cable and cleaning the contact area.


Let me know when you get a ems.

[EchoOfSilence]

lol don't even wanna try the biki huh

[NemeGuero]

^Nobody does!! Not the shop before either.. haha

Yah Luke, I don't know how to find the grounding problem though.. I did the fuel pump hard wire with 12 guage wiring.. so its not the fuel pump starving.. I'm gonna ground the MAFS, intake mani, block and go from there.. I guess.

[brainfood]

hotpipe because I recirc.

[NemeGuero]

Its already on the cold pipe. See pics above!

[brainfood]

Its already on the cold pipe. See pics above!


Yeah I noticed I was just putting my 2 cents in :) mine is there because of recirc but for non recirc I dont think it matters. I dont think there is more response either way. Its a pressurized system and if you are releasing to atmosphere even on the hot side air is going to come back from the throttle plate to the atmosphere where there is no resistance. More response with recirc over atmosphere but placement shouldnt matter on atmosphere for response