Not Recirculating Bov

[OM3GA]

I shouldnt be posting this but I was thinking about how you could use a bov without recirculating it and without having a standalone.

Couldnt you just run a Blow through maf setup?

Also where do you recirculate the Bov too? Can you just run a hose to a bung thats welded like 3 inches away from the bov? Or does it have to be a certain distance or something?

[pauliedrft]

Bobs pit stop (performance boat and car shop) in jop;in says they run the bov on the cold side close to the throttle bottle and adjust it a certain way im thinking about trying it my self .so is a friend of mine .

[OM3GA]

a certain way? wtf haha.

[duffman1278]

I recirculated mine to the intake. I just had a bung welded on and then ran my hose.

[OM3GA]

to the actual intake tube? before the turbo?

[brndck]

my bov is unrecirculated/atmospheric. my engine never stalls.i just kicked my idle speed up about 100 rpm.to properly recirc it, you want it to plug back into your air intake tubing AFTER the maf but BEFORE the turbo.

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if you run a blow thru maf, it eliminates the need to recirc it.

[S14toRPS13]

Mines currently vented to the atmosphere and I'm not using a stand alone. I had to adjust my bov to only open up at higher boost pressures, so my car won't stall. Ofcourse this leads to having slight compressor surge during light driving. I have a Synapse bov now so I'll be recirculating this one. If you still have the stock intake tube, there's an opening on the intake tube between the maf and turbo inlet. That's what I'm planning on using.

[OM3GA]

Hmm, all this sounds awesome. Thanks for all the feedback, i wouldnt mind doing a blow thru maf but i dont want to cut my cold pipe up lol Its a Greddy one made for the new style Greddy intake manifold, its one of the hardest ones to come by.

[pauliedrft]

a certain way? wtf haha.

how much pressure it takes to get it to blow off i think its set a little harder than needed so it opens only momentarily. Its all in the math .hahahaha

[zach-Ka]

I have seen most people recirc to the intake. Mine is not recirculated and mine runs fine with no stand alone or a tune.

[kouki munster]

For the most part the stock ecu on most of the factory turbo engines(I don't see the ka ecu having a problem either) can handle a open atmosphere bov, provided that the thing is properly adjusted, but it will always be more prone to stalling.

[safin]

compressor surge during light driving because the spring in the BOV is set so it only opens at high boost. Isn't this like very bad?it sounds safer to just run it to the atmosphere and mess with the rpms so it doesn't stall

[kouki munster]

compressor surge during light driving because the spring in the BOV is set so it only opens at high boost. Isn't this like very bad?it sounds safer to just run it to the atmosphere and mess with the rpms so it doesn't stall

If people took the time to set the tension on the spring properly, or would just stop being cheap bastards and buy a good quality and designed bov this would be a non-issue. But I guess some people would rather be lazy and/or save a few bucks so they can kill the bearings in their turbo.

[OM3GA]

Hmm i see, what would you say is a good bov? Of course i want the HKS one. Not just because of its sound but i like their quality of parts.

Another one i was thinking of going with is the Tial. Ill probably just recirculate it.

Ive heard of people not recirculating it and it puts the engine in a rich state during blow off which i guess wouldnt really hurt anything depending on the amount of fuel, although i have heard that you may be losing power this way

[24j0hn]

if you use a bov on the hot side(most common) you recirculate the released air after the maf and before the turbo...

[S14toRPS13]

compressor surge during light driving because the spring in the BOV is set so it only opens at high boost. Isn't this like very bad?it sounds safer to just run it to the atmosphere and mess with the rpms so it doesn't stall

There's always a big debate on this. Ball bearing turbos can withstand more turbulence from compressor surge compared to journal bearings. Just the way they're designed and the way the turbo shaft sits inside the bearings. Ball bearings also don't require the thrust bearings(which are usually the weakest part in the turbo)like journal bearing turbochargers do. The question though is, "How much is too much compressor surge?". Lots of people have ran their turbo and bov the way you mentioned for years without any issues, but then that leads to the how much is too much question. Some bov like the new HKS one doesn't have an adjustable screw IIRC. That's why I got my Synapse bov. I'm going to recirculate this one and see how it works out.

[safin]

oh I see.... good call on the synapse

[Tyler]

run a blow through, then it wont matter. thats what i have on my kat. z32 maf on the coldside, hks ssqv in the normal hotpipe spot. runs perfect

[kouki munster]

Personaly I run the synapse, but the hks is another good one.

The only down side to running a blow through is that there is a chance(very slim) in areas with a wetter climate(or if its raining) that you can get moisture collecting on the maf, and will cause a retarded rich condition.(It happened to an old z I had and ended up killing the motor)

[Tyler]

if it can get through my intake, turbo, hotpipe, intercooler, coldpipe, and still f*** my s*** up, so be it. haha in all seriousness tho, i have drifted in the wet (ie. pissing rain) a few times and its never been an issue.

[kouki munster]

It is very unlikely to happen, I've only heard of it happening to one other person other than myself, but just be aware that if your car start to run funny and it is unusualy damp and humid it might be a good idea to pop off the maf and make sure there is not any moistue on the hot wires in the maf.

[ILoveMyRHS13]

Oh people; you so sirry.Blowoff valves are the biggest waste of money on the earth. Recirculating isn't bad, but then what the hell is the point? Sell it to Captain JDM Pants for billions of dollars (just like you did).

Oh look, here's PBM's S15. Certainly they run a BOV of a track car that sees hours of abuse. Wrong.

Certainly Matt Powers' car has a BOV to handle his large turbo. Wrong.

It does NOT kill turbos. All a blow off valve does is make fart/lazer noises when you shift and decrease boost response. Everyone needs that, right?

Quote from PBM Dan when asked if they could add a BOV flange to their HMIC kit.Quote »sure if you really love your BOV, we will weld a flange for you but we recommend you dont run a BOV for drift because you dont need to release boost while modulating the throttle for counter steer during drifting, this HMIC concept is all about response and the BOV is not[/quote]
Modified by ILoveMyRHS13 at 12:42 AM 12/28/2009

[spolitte]

It does NOT kill turbos. All a blow off valve does is make fart/lazer noises when you shift and decrease boost response. Everyone needs that, right?

Your right, not having a Blowoff Valve probably won't kill your turbo the first time you let off the gas completely after being at full-boost at WOT. However, you are wrong when you say that all it does is make a fart/lazer noise and decrease boost response. It will help to prolong the life of your turbo for all of us who don't have the money to just go buy a new one whenever we want.

Besides making that noise when you let off throttle, a blowoff valve is designed to help prevent compressor surge. If you are moving mass amounts of air at an above atmospheric pressure in a system, and then decide to put a plug on the exit side of this system, this pressure is going to create a backwards wave of pressure that pushes against your turbos compressor, slowing it down VERY rapidly and in some cases even stopping it completely. THIS IS BAD!!! You don't ever want to rapidly slow or stop your turbocharger from spinning otherwise you run many risks including increasing shaft play, blowing out the bearings, or even destroying the blades.

Remember, the compressor side of your turbo is often spinning at over 100,000 RPM's. Yes you read that correctly, 100,000 rpm's, which is about 1666 revolutions per second, or 1 revolution every .0006 seconds (that is fast).

While having a BoV will not stop your turbo from eventually wearing out, it will help to prolong the life of it, even if you are not running absurd amounts of boost as is the case in a factory setup with only about 6-8 psig of boost.

But hey, if you and captain JDM pants over there have unlimited supplies of money, then heck, why spend a few hundred dollars on a piece intended to help prolong the life of your equipment when you can just go buy a brand new turbo for only a few thousand whenever you please....

[OM3GA]

sure if you really love your BOV, we will weld a flange for you but we recommend you dont run a BOV for drift because you dont need to release boost while modulating the throttle for counter steer during drifting, this HMIC concept is all about response and the BOV is not

I've been thinking about this for quite some time also, i saw that post as well.

One thing is i know that ball bearing turbos do not get as easily affected by compressor surge as much as the journal bearing turbos. Well, depending on the boost applied to them of course. I know running know bov is the best for response but how bad is it really?There are arguments everywhere.

I'm running the stock T-25 turbo at the moment and will probably end up recirculating the bov to the intake like others have mentioned.

Is it possible to weld a bung 3 inches from the bov on the hotpipe to have the bov air re-enter there? Or does it strictly have to go back to the intake? I really want to avoid compressor surge, whether or not it affects the turbo is beside the point.

[duffman1278]

Oh people; you so sirry.Blowoff valves are the biggest waste of money on the earth. Recirculating isn't bad, but then what the hell is the point? Sell it to Captain JDM Pants for billions of dollars (just like you did).

It does NOT kill turbos. All a blow off valve does is make fart/lazer noises when you shift and decrease boost response. Everyone needs that, right?Modified by ILoveMyRHS13 at 12:42 AM 12/28/2009

Factory's waste their money putting in BOV's on their production turbo vehicles also correct?

[AZ89two4Tsx]

Don't factory cars run a FULL recirculating valve?

Also, what's the point of a blow off valve in general, when you could just recirculate all that air?

Just the cool sound I'm assuming?

[ILoveMyRHS13]

Factory's waste their money putting in BOV's on their production turbo vehicles also correct?

Not too many manufacturers use atmospheric BOV's, they use diverter valves.

[OM3GA]

Not too many manufacturers use atmospheric BOV's, they use diverter valves.

Thats what the SR originally came with correct? All we try to do is keep that system by buying aftermarket valves. Its all about how the person installs it which deviates whether or not it is done properly.

[spolitte]

Not too many manufacturers use atmospheric BOV's, they use diverter valves.

Someone correct me if I'm wrong, but Nissan used atmospheric BoV's on some laurels and cefiros with the rb20det.

Thats what the SR originally came with correct?

And yes, most if not all turbo'd SR's came with a diverter valve, but by definition a re-circulated BoV is a diverter valve. All depends on how the plumbing is done.

[safin]

fart/lazer noises gets you the ladies, they are not really concerned about throttle response or the life of the tiny t25.