BOV. yes or no?

[Phillyb]

Alright so I have an hks ssq on my rb20 and after a year I must say it's getting pretty annoying. I liked it at first but I've always loved the compressor surge sound way better. So my questions are:1) Is anyone running no bov/no recirc? 2) What do I do with the vacuum line on the bov? Tap it into the IC piping? I know a lot of ppl advise against running no bov because it causes damage to the turbo over time, but i've never seen any real evidence backing up that theory. Sorry if this is a noob question btw

[NismoS-tune]

No BOV=like a boss. Get rid of it, it's overrated haha. I would too but I'm not quite sick of the HKS bov since I get less than 1300km a year on my car, don't really have time to get used to it.

My R however is a compressor surge delite. Stock thrust bearing turbo and still going strong.

To plug the vacuum line, insert a bolt that fits tightly and tie wrap it so it's stuck. Done.

[gtrte37]

been running without one since i got the car, putting on a turbosmart raceport

[Skym]

A BOV is designed to release boost pressure inside intake piping that reverses direction when throttlebody closes, hence why BOV is mounted close to throttlebody and goes across compressor wheel on turbo which slows turbo down. If turbo slows down enough, and try to get back on throttle, engine hesitates (turbo getting back up to speed) before accelerating. You do feel this in a car without a BOV.

The constant speed up, slow down damages the bearings inside CHRA (more so if car is thrashed). Non ballbearing turbochargers (as fitted to R32, R33 GTR) can supposedly take more of this abuse than ballbearing turbocharger (as fitted to RB20DET).

If BOV doesn't release enough boost pressure (doesn't open quick enough), can get some air running across compressor wheel and hear flutter sound from podfilter (used to get that with modified stock BOV at lower boost levels, where quick release was disabled to stop stock BOV from leaking at higher boost levels).

You'll notice with a good BOV, that engines reacts quicker when coming back onto throttle (known as transient response), as turbo is up to speed. Dyno's can measure transient hp / response.

[newalliance123]

Well I'm pretty sure they were first introduced to stop MAF systems from double reading air. Either way I've had no BOV for 3 years and the only issue with the setup is the car will run rich every shift in high boost which will degrade performance.

[jimBNR32]

A BOV is designed to release boost pressure inside intake piping that reverses direction when throttlebody closes, hence why BOV is mounted close to throttlebody and goes across compressor wheel on turbo which slows turbo down. If turbo slows down enough, and try to get back on throttle, engine hesitates (turbo getting back up to speed) before accelerating. You do feel this in a car without a BOV.

The constant speed up, slow down damages the bearings inside CHRA (more so if car is thrashed). Non ballbearing turbochargers (as fitted to R32, R33 GTR) can supposedly take more of this abuse than ballbearing turbocharger (as fitted to RB20DET).

If BOV doesn't release enough boost pressure (doesn't open quick enough), can get some air running across compressor wheel and hear flutter sound from podfilter (used to get that with modified stock BOV at lower boost levels, where quick release was disabled to stop stock BOV from leaking at higher boost levels).

You'll notice with a good BOV, that engines reacts quicker when coming back onto throttle (known as transient response), as turbo is up to speed. Dyno's can measure transient hp / response.

An atmos bov is the slowest for response, I have felt this in my own cars.
The pressure you loose in the system from an atmos bov means your spool up times between shifts is longer than running with no bov. Enough to make a noticeable difference!

The only thing a atmos bov is good for is noise. And I personally dont like this noise.

[Phillyb]

yeah my car is pretty bad for that right now actually. When i shift out of lets say 2nd and into 3rd, it feels like i hit a brick wall and takes a moment for the turbo to spool up again. Completely understand what your saying but I dont think the transient response is going to get any worse than it already is.

[newalliance123]

Ya exactly i have perfect response between shifts with no BOV. However it does run rich for that portion of a second. Whatever flames are cool

[Skym]

My car (RB20DET) with a recirculated Synapse BOV has what feels like 0 hesitation (drives just like a stock Skyline that has what feels like 0 hesitation, but with better response). With modified stock BOV it used to bog, then accelerate when you back off throttle, then get back onto throttle when offboost (modified stock BOV didn't release pressure under 0 on boost gauge like the Synapse BOV does, so turbo had to get back up to speed).

The 4 door Cefiro that was sold in Japan with RB20DET had no BOV, but I think turbo was non ballbearing.



I gather the only way we are going to know 100% is to put a car on dyno with a good BOV, without BOV and measure the transient hp / response.

Also the rich problem with atmosphere vented BOV could also be a reversion (air reversing direction, towards MAF when turbo slows down) problem with MAF. Some have found out, when MAF is placed further away from turbo it reduces the reversion effect on MAF and helps to reduce / fix rich problem.

[fullthrottle]

No bov on my Rb26 and I drift this piss out if it. No ill effects after 8 months

Sent from my Desire HD using Tapatalk

[Xeno-Vibe]

yes, just switch to a recirculating bov

[JVizZLe]

are you selling your bov?