Jump to content
SAU Community

Recommended Posts

Hi i know this has been spoken about many times but i can't find anything to directly answer my questions. So if you do know previous threads please let me know the links to them and don't just say its been said before.

1) Does it affect the performance of the car?

2) Does it do perminant damaged that will stay even if i unblock it? And what is this damage???

3) Does the flutter get quieter as time goes on?

Thank you in advance.

Edited by 4AL2NV
Link to comment
https://www.sau.com.au/forums/topic/155850-blocking-the-bov/
Share on other sites

Everyone has a different opinion on this. Personally, I bought an R31 w/ RB20DET off a guy who had taken the BOV off, and it made filthy compressor surge noises while running 14psi of boost. I drove it like that for 2 years (on the standard turbo!), then upgraded the turbo for an R33 S2 item because I felt like it. Ran that for another year on ~10-12psi boost with no BOV and it was fine.

That said, a proper recirculating BOV helps reduce lag between gear changes. Since my current car is standard I'll be leaving it as-is. But on the R31... it sounded wicked and didn't hurt anything.

why would you do that?

you like compressor stall between gears?

just recirculate the vented air back to the low pressure side of the intake between the a/f meter and the turbo if you don't like the noise.

1) Yes, for the worse.

2) Yes it will.

2.5) Back pressure on turbo, damage to bearings and compressor wheel.

3) No, nothing changes.

Do a search in future

Pure speculation.. Says who? Turbosmart and people flogging their products?

----

I've found no bov reduces lag between gear changes. Thats before and after. My assumption is that it must take longer to fill the IC and its piping than it does to bring the compressor back up to speed. Thats also assuming the pressure spike created due to no bov does reduce the compressors speed 'slightly'.

Its a falacy that the compressor stops/stalls or spins backwards.

Regarding drivability.. I've found no bov to cause the car to stall under some circumstances and pop/overfuel more when coming off the throttle. Apart from that the performance aspect its definitely worth while, I currently run WITH a bov because I don't like to blow flames at the cop car behind me nor do I like stalling.

Its possible a tune can prevent the pops and stalls, it was previously (Ceffy's, VLT's, XR6T (running high boost yes can their bovs) so I don't see any reason why it cant now.

Take it from a professional in the industry not the mega buck companies trying to flog off their product to you.

http://autospeed.drive.com.au/cms/A_1457/article.html

This has been covered to death and your answers have previously all been answered.

1) Yes, for the worse.

2) Yes it will.

2.5) Back pressure on turbo, damage to bearings and compressor wheel.

3) No, nothing changes.

Do a search in future

1) Alot of people say that it reduces lagginess between gear shifts and i definitely noticed this, lost all stuttering when i was changing and it seems to have more revs on hand/harder go after changes

2) no it will not have any large effects, i have never seen proof of any excess wear (it's hard to prove, but even comparing turbo life between models with or without a bov, theres very little difference) If there was any wear it'd be on the comp wheel, but as i said theres not a noticeable amount of difference

Also theres like a 15 page topic on blocking off BOV's you should probably read, majority of arguments are for blocking it off (from a performance aspect) but then there are alot of arguments against blocking it off (the sound)

If you want alot of sound = POD if you don't want much = Stock airbox

from personal experience over the last few years;

1) Not that i've noticed

2) Not that i've noticed

3) Not that i've noticed

Turbo 1, GCG highflow, on for about a year with 14 psi running through it no bov. removed it and it was perfect. No thrust movement, the usual minimal side to side movement.

Turbo 2, HKS t300s, been on for about 18 months now. originally ran 20psi and no bov. checked occasionally for thrust and lateral movement. nothing worth mentioning. I now run a type R bov recirced and that doesn't open unless I'm running more than 1bar. Checked the turbo again about a month ago, still fine.

The only problem you'll run into if you don't put a BOV on is stalling when pulling up if you have a very short, small capacity, inlet pipe.

I bloked mine off recently coz i can. really just outta curiosity and bordom. It drops the revs to the point of near stalling when working with low revs, ie. reversing slowly etc...pops flames and is making a dark patch on the rear of my car hehe.

not blowin wind up anyone's arse, i found the car a bit more punchier with it blocked off....strange coz my last rb25 was opposite. got worse and was better with it unblocked.

my two bob.

Pure speculation.. Says who? Turbosmart and people flogging their products?

----

I've found no bov reduces lag between gear changes. Thats before and after. My assumption is that it must take longer to fill the IC and its piping than it does to bring the compressor back up to speed. Thats also assuming the pressure spike created due to no bov does reduce the compressors speed 'slightly'.

Its a falacy that the compressor stops/stalls or spins backwards.

Regarding drivability.. I've found no bov to cause the car to stall under some circumstances and pop/overfuel more when coming off the throttle. Apart from that the performance aspect its definitely worth while, I currently run WITH a bov because I don't like to blow flames at the cop car behind me nor do I like stalling.

Its possible a tune can prevent the pops and stalls, it was previously (Ceffy's, VLT's, XR6T (running high boost yes can their bovs) so I don't see any reason why it cant now.

Take it from a professional in the industry not the mega buck companies trying to flog off their product to you.

http://autospeed.drive.com.au/cms/A_1457/article.html

This has been covered to death and your answers have previously all been answered.

Well...

I just got Own3d. :D

  • 2 weeks later...
why would you do that?

you like compressor stall between gears?

just recirculate the vented air back to the low pressure side of the intake between the a/f meter and the turbo if you don't like the noise.

haha i like ur avatar.. thats my useful input on this..

but why would u want to block it off?

its like keeping your mouth closed while you sneeze! give it a go - it f**ks you up, just like it will f**k up those turbos! :laugh:

my other half does that.. Makes bugger all noise. Be stuffed I could ever do it. :S

I let out a hell loud aaaaaaaaaaaaaaaaaaaaaaaaaaaahhhhhhhhhhhCHHHHHHHHHHOOOOOOOOOOCHHHHHHOOOOCHHHHHHHO

O!!

I was under the impression that you can buy a specific BOV blocking plate. I have my Blitz BOV but I don't want to block off the thick return pipe. Where can you find these blocking plates for the stock BOV?

all you need to do to block the bov is get a empty can of whatever and then take off you bov and trace it onto the can and cut it out. then just block the vac hose and flutter like a fully sik vl bruddaz.

note on an r33 youll have some fun. itll stall on low revs and black shit will come out the exhaust on gear changes. try and pull into a park in the city and then stall. you lose you power steering and then you on you unassited brakes trying not to hit the car next to you :S good luck :happy:

Pure speculation.. Says who? Turbosmart and people flogging their products?

Good point... It can damage a standard ceramic turbo tho... blew my ex wheel and comp wheel clean off...

But its all personal preference with the noise n shit... some sound good, the ones with fat ass intercoolers... some sound ghey like u wana kick the prick driving the car in the teeth.. but if you like attention like going to brunette to blonde they go for it :D

Ive got a HR31 with a rb20det that came from the factory with no bov and flutters all day long.

No performance issues, no problems.

I suggest this thread is closed with a link to the previous one.

Edited by Rolls

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • I came here to note that is a zener diode too base on the info there. Based on that, I'd also be suspicious that replacing it, and it's likely to do the same. A lot of use cases will see it used as either voltage protection, or to create a cheap but relatively stable fixed voltage supply. That would mean it has seen more voltage than it should, and has gone into voltage melt down. If there is something else in the circuit dumping out higher than it should voltages, that needs to be found too. It's quite likely they're trying to use the Zener to limit the voltage that is hitting through to the transistor beside it, so what ever goes to the zener is likely a signal, and they're using the transistor in that circuit to amplify it. Especially as it seems they've also got a capacitor across the zener. Looks like there is meant to be something "noisy" to that zener, and what ever it was, had a melt down. Looking at that picture, it also looks like there's some solder joints that really need redoing, and it might be worth having the whole board properly inspected.  Unfortunately, without being able to stick a multimeter on it, and start tracing it all out, I'm pretty much at a loss now to help. I don't even believe I have a climate control board from an R33 around here to pull apart and see if any of the circuit appears similar to give some ideas.
    • Nah - but you won't find anything on dismantling the seats in any such thing anyway.
    • Could be. Could also be that they sit around broken more. To be fair, you almost never see one driving around. I see more R chassis GTRs than the Renault ones.
    • Yeah. Nah. This is why I said My bold for my double emphasis. We're not talking about cars tuned to the edge of det here. We're talking about normal cars. Flame propagation speed and the amount of energy required to ignite the fuel are not significant factors when running at 1500-4000 rpm, and medium to light loads, like nearly every car on the road (except twin cab utes which are driven at 6k and 100% load all the time). There is no shortage of ignition energy available in any petrol engine. If there was, we'd all be in deep shit. The calorific value, on a volume basis, is significantly different, between 98 and 91, and that turns up immediately in consumption numbers. You can see the signal easily if you control for the other variables well enough, and/or collect enough stats. As to not seeing any benefit - we had a couple of EF and EL Falcons in the company fleet back in the late 90s and early 2000s. The EEC IV ECU in those things was particularly good at adding in timing as soon as knock headroom improved, which typically came from putting in some 95 or 98. The responsiveness and power improved noticeably, and the fuel consumption dropped considerably, just from going to 95. Less delta from there to 98 - almost not noticeable, compared to the big differences seen between 91 and 95. Way back in the day, when supermarkets first started selling fuel from their own stations, I did thousands of km in FNQ in a small Toyota. I can't remember if it was a Starlet or an early Yaris. Anyway - the supermarket servos were bringing in cheap fuel from Indonesia, and the other servos were still using locally refined gear. The fuel consumption was typically at least 5%, often as much as 8% worse on the Indo shit, presumably because they had a lot more oxygenated component in the brew, and were probably barely meeting the octane spec. Around the same time or maybe a bit later (like 25 years ago), I could tell the difference between Shell 98 and BP 98, and typically preferred to only use Shell then because the Skyline ran so much better on it. Years later I found the realtionship between them had swapped, as a consequence of yet more refinery closures. So I've only used BP 98 since. Although, I must say that I could not fault the odd tank of United 98 that I've run. It's probably the same stuff. It is also very important to remember that these findings are often dependent on region. With most of the refineries in Oz now dead, there's less variability in local stuff, and he majority of our fuels are not even refined here any more anyway. It probably depends more on which SE Asian refinery is currently cheapest to operate.
    • You don't have an R34 service manual for the body do you? Have found plenty for the engine and drivetrain but nothing else
×
×
  • Create New...