HKS BOV Question ... yes another one
Oct 13, 2006 | 12:36 PM
#1
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From: Where you come to vacation and go home on probation! Vegas!
HKS BOV Question ... yes another one
Before I get told to search I already did ... and just got a bunch of threads with people asking about VTA and crap like that.
So here is the deal ..... I finally got my new intercooler installed with new piping and a new HKS BOV. The car runs awasome now and feels great except for one thing.
Now when crusing on the freeway and in 5ht gear i'll some time accelerate a little and the then let off a little. The BOV opens up just a bit and the whole motor studders in a sense. Any idea of how to fix this? or is this normal with the HKS BOV? its self adjusting like the stock one so I can mess with the spring or screw at all.
Also NO I am not VTA and 2nd I already check for boost leaks.
So here is the deal ..... I finally got my new intercooler installed with new piping and a new HKS BOV. The car runs awasome now and feels great except for one thing.
Now when crusing on the freeway and in 5ht gear i'll some time accelerate a little and the then let off a little. The BOV opens up just a bit and the whole motor studders in a sense. Any idea of how to fix this? or is this normal with the HKS BOV? its self adjusting like the stock one so I can mess with the spring or screw at all.
Also NO I am not VTA and 2nd I already check for boost leaks.
Oct 13, 2006 | 12:47 PM
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From: somewhere testing various tires, brakes, and suspensions.
https://www.evolutionm.net/forums/sh...5&postcount=10
Specifically, this part. That sounds like comp. surge.
Hope that helps some. I do not know about adjustment.
Specifically, this part. That sounds like comp. surge.
Originally Posted by Mike@Forge
The HKS valve is unique in that it's spring is used to keep the valve closed at idle/under vacuum, preventing it from being "pulled" open. And while this is great when used in an atmospheric configuration, so as no metered air is lost from the system through the open valve, this principle does not apply when the HKS valve is setup to recirculate. When recirculating, the valve needs to be "pulled" open at idle, so the spring is subsequently too stiff to allow this to happen.
Additionally, in an atmospheric configuration, when under load/boost, obviously the HKS valve will be "pushed" shut from a combination of the pressure reference from the intake manifold and the positive pressure within the piping holding the valve's "disk" against its seat, but at throttle lift, when there is a residual amount of pressure needing to be released, that pressure within the intercooler piping is still "pushing" the valve's disk closed. And though the intake manifold has also returned to vacuum, at least momentarily, and the valve should be "pulled" open, as mentioned above, the spring used in the HKS valve is designed to prevent the valve from opening under vacuum or at idle, so the HKS valve only opens in response to a change in the pressure differential between the intercooler piping and the throttle body.
In my opinion, this change takes such a period of time to occur before opening the valve, that the residual charge pressure has already backed up into the compressor wheel on the turbo, thus slowing it down, and potentially even creating lag, or worse, possibly compressor surging.
Again, the above is my personal opinion of the operation of the HKS valve and is fully subject to argument, or HKS can speak for themselves.
Additionally, in an atmospheric configuration, when under load/boost, obviously the HKS valve will be "pushed" shut from a combination of the pressure reference from the intake manifold and the positive pressure within the piping holding the valve's "disk" against its seat, but at throttle lift, when there is a residual amount of pressure needing to be released, that pressure within the intercooler piping is still "pushing" the valve's disk closed. And though the intake manifold has also returned to vacuum, at least momentarily, and the valve should be "pulled" open, as mentioned above, the spring used in the HKS valve is designed to prevent the valve from opening under vacuum or at idle, so the HKS valve only opens in response to a change in the pressure differential between the intercooler piping and the throttle body.
In my opinion, this change takes such a period of time to occur before opening the valve, that the residual charge pressure has already backed up into the compressor wheel on the turbo, thus slowing it down, and potentially even creating lag, or worse, possibly compressor surging.
Again, the above is my personal opinion of the operation of the HKS valve and is fully subject to argument, or HKS can speak for themselves.
Oct 13, 2006 | 01:19 PM
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From: Spec-Ops Motorsports, Fayetteville, NC
its from partially opening... its pretty normal... its not compressor surge. compressor surge happens when the valve isnt opening or recirc'ing properly. my 1g was doing that when i rtv'd the flange and accidentally sealed one of the holes
Oct 13, 2006 | 01:20 PM
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From: somewhere testing various tires, brakes, and suspensions.
Originally Posted by M3this
SO there is no real way to fix this ???
Was the IX leaking on you? In not, Id say run that. You can sell that HKS for some good mulla to a honda guy, then get more upgrades with that cash.
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Oct 13, 2006 | 01:21 PM
#8
My SSQV never did that on my 240sx w/ the RB25... I noticed the GFB I used to have on my Evo did that alot too. After reading the little article above, probally a different kind of fluttering with the ssqv though.
Oct 13, 2006 | 01:34 PM
#9
same thing happens to me on the freeway in 5th gear under light to medium throttle. i have a greddy type rs bov though. try adjusting it to a "softer" setting, that's what i did and it's noticeably better. i do have a slight flutter every now and then though.
Last edited by Lancer EVO IX; Oct 13, 2006 at 01:36 PM.
Oct 13, 2006 | 01:35 PM
#10
Originally Posted by bigric09
its from partially opening... its pretty normal... its not compressor surge. compressor surge happens when the valve isnt opening or recirc'ing properly. my 1g was doing that when i rtv'd the flange and accidentally sealed one of the holes
Oct 13, 2006 | 02:06 PM
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Originally Posted by SmikeEvo
Well, yes there is - put your IX dv back on.
Was the IX leaking on you? In not, Id say run that. You can sell that HKS for some good mulla to a honda guy, then get more upgrades with that cash.
Was the IX leaking on you? In not, Id say run that. You can sell that HKS for some good mulla to a honda guy, then get more upgrades with that cash.
I can deal with it as its not that big of a deal, just wanted to see if there was a way to fix it and if anyone else was having this problem.
Oct 13, 2006 | 02:08 PM
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Originally Posted by Lancer EVO IX
same thing happens to me on the freeway in 5th gear under light to medium throttle. i have a greddy type rs bov though. try adjusting it to a "softer" setting, that's what i did and it's noticeably better. i do have a slight flutter every now and then though.
Also can someone tell me why fluttering is bad? I mean I know why fluttering would be bad on boost (as it would be leaking) but off boost why is fluttering bad?
Oct 15, 2006 | 04:16 PM
#14
Originally Posted by M3this
Yea only reason I got rid of the stocker is my Full-Race Intercooler piping was set up for a weld on flang. I went with the HKS as I knew it was self adjusting and my freind at BOSS reccomend it. I also plan on going larger turbo so it didnt make sense to keep the stock one.
I can deal with it as its not that big of a deal, just wanted to see if there was a way to fix it and if anyone else was having this problem.
I can deal with it as its not that big of a deal, just wanted to see if there was a way to fix it and if anyone else was having this problem.
