chiplee Posted January 31, 2003 Report Share Posted January 31, 2003 Well over the years the general consensus has been that the second port on an HKS racing BOV gets left open. And that to make it work one must supply a nearly dedicated, large, strong vacuum signal to the port visible in this pic. I probably asked every single person that has this BOV in their quest and got that same answer, and I suspect that theory came from CNM. If you have it, and that works for you, fine. I could not, no matter how hard I tried, make this unit work with it setup that way. I've been meaning to add a 3/8th port to my plenum for use with the BOV exclusively, but before I got to that I got to snooping around the HKS website and read this line "HKS Racing Bypass Valves function similar to the Standard Bypass Valves, but incorporate an additional pressurized port to aid under severe boost conditions. The Racing Bypass Valve can also be used as a safety "pop-off" valve if the second port is connected to a pressure source that does not see vacuum." So I thought what the hell? I'll connect that other port to a vacuum source before the throttle plate and see what happens. Well I was immediately thrilled. I got to see how the safety valve function works because I had adjusted the bolt all the way out to make it work with a single vacuum line hooked up, and it wouldn't build more than 12 psi. This BOV is rated at 12-18psi so that tells me it's working perfectly if it opened under 12 psi with a pressure line attached to the second port and the adjuster bolt backed all the way off. When I tightened that bolt 3/4 of the way down I was able to build 18 psi and blow offs are crisp and instant with absolutely no chirping compressor stall sound at all. Before it would do this half --------------- compressor stall slash blow off BS that was killing my turbo. I wish I'd have thought outside the box 3 years ago. I might have saved alot of miles on this turbo. I don't know if that second port is supposed to get a pressure only source for the "extreme boost" conditions that HKS sentence talks about or a manifold vacuum souce, but I plan to try both and see how it works. It really can't hurt anything. It's nice to use it to its full potential either way. If a vacuum line pops off the wastegate actuator and the turbo tries to dump 40psi into my engine, it would be nice to have a safety valve inline that would prevent that. http://hksusa.com/images_products/L_1271.jpg Link to comment Share on other sites More sharing options...
Boosted_One Posted January 31, 2003 Report Share Posted January 31, 2003 I have seen them hooked up both ways. Problem is you'll have a harder time holding boost in with that configuration. This is the reason HKS came out with the sequential BOV. Actually HKS dropped the racing BOV we have at one point but were having problems with the sequential BOV and I guess the want for the racing BOV was really high. After all the racing BOV is the original real deal unit. No flash and all function. I have never had a problem with the single line. I made sure it was a really strong vacuum source. Had it like this for 4 years now. On the dyno you could really hear it blowing off. I am surprised you had problems with it. Several years ago Steve at TEP told me to intall it the way I have it. That's where I got my info from. Link to comment Share on other sites More sharing options...
chiplee Posted January 31, 2003 Author Report Share Posted January 31, 2003 mike have you seen the getaway in stockholm video with the 400+hp cosworth excort? All you hear is this guy's blow off valve frickin' psht! psht! over and over again even when he doesn't shift. Well that's how mine works now. I haven't heard a single hint of compressor stall since I hooked it up this way. I the lack of pressure release was what was causing my dipstick to pop out too... It doesn't seem to be doing it anymore. I wish I knew why it never worked the other way. I knew you and some others swore by this BOV, but it just never did work right for me. Now it's the best. It feels so much healthier for the turbo. Gentle driving hard driving, doesn't matter, it blows off when I shift or let off the gas, instantly Link to comment Share on other sites More sharing options...
Boosted_One Posted January 31, 2003 Report Share Posted January 31, 2003 Hmm sounds like it is running like a bypass valve. Kinda like the way the 2G BOV work, they kinda govern boost that's why they leak like that. So with that in place how would you run 20 psi if the spring is rated at 18psi? You would end up overriding the boost controller. I'll give it a try sometime. Good post! Link to comment Share on other sites More sharing options...
chiplee Posted January 31, 2003 Author Report Share Posted January 31, 2003 Well my understanding was that the only difference between a bypass and a blow off was where the air went. On a bypass the air goes back to the turbo inlet, and on a blow off it vents to the atmosphere. If you meen it's functioning like a pop off or safety valve or if my understanding of the difference between BOVs and bypass valves is wrong let me know. The last step in this little experiment will be to connect a source that sees vacuum to the second port on the bov. The HKS website is not very detailed but that one sentence that I spoke of above makes me think that a source that only sees pressure would be used only when you want it to act as a safety valve which prevents over boost. I gather loosely from that same sentence that perhaps source connected to the second port that does see vacuum would simply improve performance, rather than cause the valve to act as a safety valve. I'm not sure, but since it seems there's no place to fine a definitive answer, I'm just going to connect it both ways and conduct road tests to make my own determinations. I can handle it connected this way for daily driving. It made 18 psi on the highway today in a 5th gear pass and the adjuster bolt isn't nearly all the way in. when the roads dry up here I'll know more about how much boost I can make in each vacuum line configuration, and where the adjuster bolt needs to be. Link to comment Share on other sites More sharing options...
Boosted_One Posted January 31, 2003 Report Share Posted January 31, 2003 I think the term BOV could go on and on defining it. When I first got into turbocharging in 1991 the term BOV was vastly different than it is used today. A BOV was a safety device used to regulate boost, ala a pop off valve. Anyhow if you look at how the 2G bov leaks past xx amount of boost you can get an idea on what I mean by BPV. From what I have read up on 2G BPV they actually leak to control boost. And let me tell you they really leak boost bad. Keep us informed on how it operates for ya. Link to comment Share on other sites More sharing options...
chiplee Posted February 3, 2003 Author Report Share Posted February 3, 2003 well I got to do some testing this weekend and it appears to work flawlessly with the second port connected to a source that only sees pressure, ie. source before the throttle body. Â With that port connected to a source that sees vacuum it seemed I would have more boost leak problems but I wasn't sure. Â It also didn't seem to act as fast. Â Sorry for going on about something just working like it's supposed to but the way it works now is amazing to me. Â I've had so much compressor stall that I was getting used to it. Â Now I get absolutely none. Â I love going through the gears now and getting a nice crisp pressure release every shift Oh and Mike, I threw a bottle of the NOS offroad octane booster in it and tried 20psi. Â It held perfectly and I still have room to tighten the bolt so I assume it's just under rated, unlike these noise maker toys that are rated from 10 to 35psi. Link to comment Share on other sites More sharing options...
Mad_Mike Posted February 3, 2003 Report Share Posted February 3, 2003 Good goin Chip. Can the wastegate line be used as a pressure source as long as it is before the boost controller? Mike Link to comment Share on other sites More sharing options...
zactek Posted February 4, 2003 Report Share Posted February 4, 2003 Chiplee, I've read your posts and I'm trying to figure out what you did. I've had the HKS BOV for a few years now and still get a little stall at lower boost pressures, the BOV doesn't seem responsive until I get on the highway,then it releases everytime I let go of the gas. Are you using both ports on the BOV? Thanks. Link to comment Share on other sites More sharing options...
importwarrior Posted February 4, 2003 Report Share Posted February 4, 2003 some pics would be nice!!!!!! if possible! thanks! Link to comment Share on other sites More sharing options...
Mr._HP Posted February 4, 2003 Report Share Posted February 4, 2003 I second the notion of pics or more detailed explaination of what was done. I am experiencing the same stall problems you mentioned chip. Ever since I did the bigger turbo upgrade I've never been able to get the BOV to release quickly. It's always a chirp/poosh sound. : Unless I'm into the throttle and back-off very quickly will it get a somewhat crisp pressure release. I think all of us could benefit from how you've hooked up your BOV Chip. Could you give the exact locations used for your vaccum lines (sources and corresponding port on BOV)? Link to comment Share on other sites More sharing options...
Sean_P Posted February 4, 2003 Report Share Posted February 4, 2003 Chip I just perchased a xs type H. I wanted a blow off valve not a noise maker like the RFL model. You seem to be saying the others are not good. Can you explain why the hks is better and what you think of the xs type h? thanks Link to comment Share on other sites More sharing options...
chiplee Posted February 4, 2003 Author Report Share Posted February 4, 2003 Pics are possible but let me give it one more go at explaining before I break out the digicam... If you look at the pic in post 1 of this thread you see one vacuum port on top of the BOV near the adjustment bolt. That was previously the only port one would use. It get's connected to a manifold pressure source that sees vacuum. On a stock setup the port closest to the firewall in the row of three ports on the TB is probably what you used. If not make it that way. T off of that line and connected to the port in the picture above.. The need for this port to have a "dedicated" source is greatly reduced when we use the other port, so T fittings are fine. If you have the HKS racing BOV you may know that there is a second port diagonally opposite the one we just talked about. Connect this port to a source that only sees pressure. Examples are OVCP port, Turbo Compressor housing, basically anywhere between the turbo and the throttle body. But not after the Throttle body. Again, use a T- fitting. The port on the TB just prior to the Throttle plate would work fine. I believe on a stock car this line goes to the secondary air cleaner. I don't recall completely so don't get wrapped around the axle about that, just use any of the ports I described. Don't be surprised if you need to tighten your adjuster bolt to get it to hold the boost level you were running without the second port in use. I'm having no trouble holding all the boost I want though so I think you'll like the results once you make the adjustments. Before this, turning the adjuster bolt really didn't do anything. Now it feels like it's an actual adjustment. Some day I want to find a way to figure out how much pressure it will release at, so I can set it at a max safe boost level incase of wastegate actuator failure or blown wastegate actuator vacuum line. This would add a margin of safety to the engine and hopefully avoid an engine killing boost spike. Chip I just perchased a xs type H. I wanted a blow off valve not a noise maker like the RFL model. You seem to be saying the others are not good. Can you explain why the hks is better and what you think of the xs type h? thanks The HKS Racing is IMO, the best no frills BOV available. Not loud, not for show and not expensive. I think it works better than other units that sell for their look and noise level. I can't honestly rate your model in particular, because I've never used it. I'm sure it will work well. I don't like when performance parts makers begin to cater to ricers by advertising calateral or secondary functions of their parts to gain appeal and notoriety with people who aren't about performance. I've leaned more toward making my car a show piece lately but when I bought it that was not my intention. I personally wouldn't make a car loud and pretty before I made it haul a**, after is fine. Link to comment Share on other sites More sharing options...
zactek Posted February 5, 2003 Report Share Posted February 5, 2003 So Chiplee, can I connect the second line to a T that splices in between the OVCP port (I have the TEP OVCP) and the wastegate (I have a new single port wastegate)with no problem? I never knew that the OVCP port doesn't see any vacuum...... I always wondered why the HKS BOV doesn't release so quickly, I gotta try this. Thanks Chip! Link to comment Share on other sites More sharing options...
chiplee Posted February 5, 2003 Author Report Share Posted February 5, 2003 yep that will work just fine. if you think about it enough it makes sense. The pistons are trying to pull air in as they go down. On a naturally aspirated engine, that is the only thing that makes air enter the engine. On a forced induction engine a turbo blows air into the engine. Well the turbo spins at idle, so naturally if you pull a vucuum line off of a source before the throttle plate you will feel air blowing out of it, i.e. a pressure only port. all sources after the throttle plate are affected by the suction of the pistons because they are blocked off from the pressure of the turbo by the nearly closed throttle plate. It's really quite amazing that engine management systems can ever keep up with the extremely dynamic, and ever changing parameters inside an engine, especially a turbo'd engine. Link to comment Share on other sites More sharing options...
DanMitsu Posted February 5, 2003 Report Share Posted February 5, 2003 Hey, Chip your right.. that sounds a hell of alot better, than before. i have replaced the diaphram, the spring...becasue i thought, it was'nt blowing enough off anymore. or i was just getting used to it. (the sound) Any ways, before, all you could hear was the wastgate, chirping.. an now the bov is speaking back up.. thankx for sharing the info. An it finally seems to be more in step,. when slaming the gears... thankx Link to comment Share on other sites More sharing options...
zactek Posted February 5, 2003 Report Share Posted February 5, 2003 Thanks Chip, what you said makes a lot of sense. All this time I thought that I just wasn't running enough boost or had it adjusted wrong, I'm gonna try this!! Thanks for the info!! Link to comment Share on other sites More sharing options...
DJpowerHaus Posted February 5, 2003 Report Share Posted February 5, 2003 Im pretty impressed with the Turbo XS Type H. I'm just wondering in you guys have short shifters. There is nothing like a "Pst" for a .25 second shift. (okay. Maybe I havent timed it) Link to comment Share on other sites More sharing options...
chiplee Posted February 5, 2003 Author Report Share Posted February 5, 2003 yup, sure do have a ST Shifter. I've never timed it either but I've measured the travel from 3rd to 4th and it's just over 2.5 inches, so it's got to be quick. It feels perfect when I shift now. Just like it's meant to be I suppose, but new to me. Link to comment Share on other sites More sharing options...
importwarrior Posted February 5, 2003 Report Share Posted February 5, 2003 what kind of shifter do you have? Link to comment Share on other sites More sharing options...
chiplee Posted February 5, 2003 Author Report Share Posted February 5, 2003 it was a gift, but it looks like the Bain industries one Link to comment Share on other sites More sharing options...
Sean_P Posted February 5, 2003 Report Share Posted February 5, 2003 Chip did you put a bend in it ? and if not how do you like the straight shifter design? it was a gift, but it looks like the Bain industries one http://users.starpower.net/mtech/fuel_injection_specialties023010.jpg Link to comment Share on other sites More sharing options...
chiplee Posted February 5, 2003 Author Report Share Posted February 5, 2003 Mine came with a bend. I think I remember a GP where the buyers had the option of bent or straight. Like I said though this one was bought for me by a friend, so I just installed it and I love it. It clicks into gear now with a nice clean new feel. Actually that and the "input shaft coupler knuckle" at the joint between the steering column and the steering gearbox, has had an amazing affect on the way my car feels. If you had ridden in this car when I bought it, then rode in it now, you'd be amazed at how tight it feels. It used to bounce like a hooptie. It had 6+ inches of steering wheel play, it would road wander, the engine was junk. it's just a whole new car man, and to answer your question, the short throw shifter contributed alot to that. Link to comment Share on other sites More sharing options...
spooling Posted February 8, 2003 Report Share Posted February 8, 2003 hey chip,i have the same bov on my 88, mine use to do that,it blew off all the time, really loud and crisp. Then one day it just stop blowing off.I let this guy mess with the car and he said that it was blowing off to soon,he said he adjusted it but now it does not blow off at all.on mine one port is left open i really don't know what this guy did but i miss that sound.some advice?can u email me? i don't come here much.bknycivic@aol.com thank you. Link to comment Share on other sites More sharing options...
chiplee Posted February 8, 2003 Author Report Share Posted February 8, 2003 my advice is read this thread, try the steps I listed to make it work and let us know if that doesn't make it better. Link to comment Share on other sites More sharing options...
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