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Stopping Your BOV From Leaking - A How To

Jay95R33

By Jay95R33,
in Engines & Forced Induction

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R31 POWER Mentor

R31 POWER

Posted
Posted

I did it today and the noise is good ppoorrsshh but I miss the pphhsstt.

What will happan if I disconnect the return air(from bov to mouth of turbo)and let it free to the atmoshere,will it stall and piss fart around and will the noise be louder btw it' a RB20.

Roy Grand Master

Roy

Posted
Posted

Can you submerge the outlet in a glass of water, then blow thru the small hole next to the valves diaphragm. Do up see bubbles

Im curious to know if the OE BOV has a check valve in their somewhere. Or have you checked that irresprective which end your blowing in, air still passes thru.

Good find.

Jay95R33 Grand Master

Jay95R33

Posted
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Posted
Originally posted by Roy

Can you submerge the outlet in a glass of water, then blow thru the small hole next to the valves diaphragm. Do up see bubbles

Im curious to know if the OE BOV has a check valve in their somewhere. Or have you checked that irresprective which end your blowing in, air still passes thru.  

Good find.

G'day Roy,

Yepp, it flow's both ways. I checked this out just to make sure. Strange hay. Not sure what it's meant to do like it is, maybe it makes the transision from BOV closed to BOV open smoother or something? I don't know... But mine does feel a bit snappier while on boost.

R31 Power - if your ECU is anything like the ECU's on the R33 and R32's then you might get the stalling and overfueling problems that some of the other blokes have had went they run a BOV that vents into the air. :)

  • 9 months later...
sweetr33 Experienced

sweetr33

Posted
Posted

Well i cant say i am a fan of this idea. I tried it myself and u can notice its doing something different. I noticed when adding slight throttle from say a cruize situation the accelaration is upped as the bov cant leak excess air back into the chamber. This is i think a not so good thing. Didnt notice any differences in performance when in full throttle position though. I went to the track with it blocked off and on my last run unblocked it, taking it back to stock and i ran .4 of a second quicker. Not sure if the 2 are related but i am not convinced this mod does anything sufficient

RaseR Collaborator

RaseR

Posted
Posted

I also tested this mod the other day on my R32 GTS-t using a piece of tape to cover the hole, the BOV definitely sounded different....For a start - less air recirculation sound when the turbo spools up, normally when venting the BOV sounds like this: WWTTSSSSSSSSSSSHHHHH, afterwards it sounded the same at high rpm/boost but on a light to midrange throttle backoff it would flutter (kinda like this: TSHH TTTT TTT TT) and caused the motor to hesitate slightly.

I removed the tape and the hesitation disappeared and the BOV sounded as normal - so I can't say I was all that impressed with the result, but it is interesting how different ppl have had totally different results!

Busky2k Veteran

Busky2k

Posted
Posted

I did the mod and my BOV sounds pretty different. Not a long pssshhh anymore. More of a quick sshtt and thats about it. Doesnt sound as nice. But it does certianly hold booster better. I'll be leaving it modded!

Guest RedLineGTR

Guest RedLineGTR

Posted
Posted
It's not actually a leak....Nissan put it there for a reason. Did any of you happy little modders find out what it does before you changed it..........Just curious... ;)

From what i have noticed and heard also, it is designed to stop boost hitting so hard when it kicks in gives a more smoother boost delivery when boost is created it does it by bleeding abit of the air.

Jay95R33 Grand Master

Jay95R33

Posted
  • Author
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i really want to do this mod but whats the conclusion result? should i or shouldn't i?

I think it really comes down to personal taste and your driving style.

Some people like the way it feels once modded, others don't.

The biggest difference I found (in my car) is that it seems to come on boost harder and a bit faster.

When I had the car on a dyno, the operator was supprised to see my car having useable boost at 1800rpm !! And looking at the dyno printout, it goes from 46rwkw at 60km/h (4th gear) to 90rwkw at 78km/h. That's close to double the power in 18km/h - I better add in a comment that I'm not interested in the actual amount of power, but it's the power curve that is interesting, otherwise I know it's gunna start up that "can't trust dyno's" crap...

And all I had was a 3 inch exhaust, FMIC, 12psi and the BOV mod.

So as you can imagine, having more power lower in the rev range makes the 'power band' bigger. Well that's my theory anyway.

One question I do have though, some people have mentioned that doing this mod takes away the linear feel of the throttle. Does that mean that everyone that has a after market BOV that plumbs back get's the same results?? I've never used one so I wouldn't know.

J

  • 1 month later...
sweetr33 Experienced

sweetr33

Posted
Posted

yeah i have changed my mind, i did this mod again out of pure boredom at home, and have been monitoring it, i notice its more snappy onto boost, and not asmuch throttle needed to continue motion. Liking the noise too.

  • 2 weeks later...
Freebaggin Proficient

Freebaggin

Posted
Posted
That's great news freebaggin - thanks for going to the effort of doing a comparison.

J

Thanks to you for sure, I had basically forgotten that the stock BOVs leak and your post promted me to do something about....fantastic result for the cost and effort involved!

Busky2k Veteran

Busky2k

Posted
Posted

Freebaggin, very interesting stuff indeed. Btw Im interested in seeing the boost curves. It seems as if the latter run was running a smidgen more boost, well just seems like it anyway...

Good stuff!!!

Freebaggin Proficient

Freebaggin

Posted
Posted
Freebaggin, very interesting stuff indeed. Btw Im interested in seeing the boost curves. It seems as if the latter run was running a smidgen more boost, well just seems like it anyway...

Good stuff!!!

Well I suppose it's more that the turbo might be running more efficienctly as well, not having to increase shaft speed to counter the bleed of and as the boost chart shows, the curve is a smidge more consistant and maybe that's all the turbo needs to provide better grunt..???

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