big-phil Posted February 15, 2006 Share Posted February 15, 2006 I've done some searching but still not sure, where do I put a BOV? near the throttle body, or near the turbo. don't forget I still have an Air flow meter. I've read that you should not use a bov when you still have the afm, but I'm running 15-16 pounds of boost, and feel that I need one. Plus they sound cool! Quote Link to comment Share on other sites More sharing options...
zguy36 Posted February 15, 2006 Share Posted February 15, 2006 Put the BOV nearest to the throttle body. The purpose of the BOV is to prevent pressure waves from bouncing back and forth between the throttle plate and the turbo, which is bad when the pressure wave bounces back into the turbo. If you put the BOV near the throttle body, when the throttle goes shut, there is a pressure relief right by the shut throttle body. If you put the BOV near the turbo, there is enough momentum in the air flow that pressure will build against the throttle plate and bounce back towards the turbo and reliev pressure there. I don't know if there is much of a noticible difference between the two ways to do this, but mounting the BOV nearer to the throttle plate will prevent any pressure surges. Quote Link to comment Share on other sites More sharing options...
Thumper Posted February 15, 2006 Share Posted February 15, 2006 YES YOU NEED ONE. Its bad to run stock boost without a BOV let alone 15psi. You should put a BOV 4-6" before the TB. If you are running an afm you need to recirculate the bov into your intake tract. After the afm but before the turbo. If you do not recirculate it and let it vent to the atmosphere then your car will run really rich when you let off the throttle. If you are coming to a stop it might even stall. Quote Link to comment Share on other sites More sharing options...
big-phil Posted February 15, 2006 Author Share Posted February 15, 2006 Thanks Thumper, and zguy36, thats what I was looking for, and I will run it back in after the afm, before the turbo. Man I need to get one!!! I see on e-bay one for an eclips, are those any good, I really don't have 100 bucks to spend on one, but this one is about $35 shipped Quote Link to comment Share on other sites More sharing options...
big-phil Posted February 15, 2006 Author Share Posted February 15, 2006 Take a look at this one for a Supra, will it work? I know where there is a Supra at a junk yard and I can probly get this one cheap. will it let me put the bypass air back to the intake? http://cgi.ebay.com/ebaymotors/mk3-supra-BOV-mkiii-ma70-7mgte-blow-off-valve-bypass_W0QQcmdZViewItemQQcategoryZ33742QQitemZ8038116735QQrdZ1 Quote Link to comment Share on other sites More sharing options...
Thumper Posted February 15, 2006 Share Posted February 15, 2006 Supra one is not a great one but will work if you have no choice. Do not get a 2nd gen eclispe, talon bov. Your best oem bov is a 1st gen Bov off of a eclipse or talon. They can be had for $20 at a junkyard or $30-40 off of ebay. I ran one of those for awhile and it worked perfectly. Quote Link to comment Share on other sites More sharing options...
zguy36 Posted February 15, 2006 Share Posted February 15, 2006 I used one off of a DSM and it worked great as well. It didn't work however when I upgraded to a larger intercooler. With the larger mass of pressurized air in the NPR intercooler, the DSM blowoff valve didn't have enough flow capability. Quote Link to comment Share on other sites More sharing options...
Lason Posted February 15, 2006 Share Posted February 15, 2006 You could also run a open BOV before the MAF/AFM and not recirculate it. As long as you dont dump metered air into the atmosphere your good. I have seen people run them right on their air/air intercoolers with good luck. Quote Link to comment Share on other sites More sharing options...
Thumper Posted February 15, 2006 Share Posted February 15, 2006 On z cars the afm is before the turbo so there is no pressure. So DO NOT install the bov any where before the turbo cause it just won't work right. Quote Link to comment Share on other sites More sharing options...
Lason Posted February 15, 2006 Share Posted February 15, 2006 On z cars the afm is before the turbo so there is no pressure. So DO NOT install the bov any where before the turbo cause it just won't work right. OOPS, my bad, I didnt even bother to ask if it was a drawthrough or blowthrough MAF setup. Yeah on a drawthrough your only option is recirculate it or of course convert to speed density. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted February 15, 2006 Share Posted February 15, 2006 i just sold my DSM BOV.. anyway... the 1st generation Eclipse/DSM blow off valve will hold up to 18psi, and you can crush it to handle 27psi!! and it sounds sweet.. ask Mnelson.. or Mobythevan (Brian sold his car to Nelson) .. which ran a DSM BOV Quote Link to comment Share on other sites More sharing options...
dapiper Posted February 16, 2006 Share Posted February 16, 2006 Use the 944 turbo valve; has positive seal rubber seat. I have spare somewhere if your strapped. Quote Link to comment Share on other sites More sharing options...
Sparky Posted February 16, 2006 Share Posted February 16, 2006 If you wanted to spend a little more cash you could buy a hybrid BOV. this one by gofastbits http://www.gofastbits.com.au/index.php?parentid=products&option=products&sub_option=bovs&sub_sub_option=hybrid vents back into the intake system between the AFM and turbo inlet as well as venting to atmosphere for that special BOV sound. I ran this one on my car for around 300 miles before the car went to paint jail. I only heard it a few times but when I did it was very nice...but! since it does vent back to the intake system the magnitude and length of the burst is lessened. Since coming back from paint jail I've gone standalone management and blocked off the bypass on the BOV. we shall see how loud it is after that. Quote Link to comment Share on other sites More sharing options...
myplasticegg Posted February 16, 2006 Share Posted February 16, 2006 What are you more worried about breaking? turbo or TB. I've always put them right near the turbo. Quote Link to comment Share on other sites More sharing options...
Thumper Posted February 16, 2006 Share Posted February 16, 2006 What are you more worried about breaking? turbo or TB. I've always put them right near the turbo. When the tb is closed all that air hits a wall and reverberates backwards. It is strongest and most efficient to vent close to the tb. If you do by the turbo then it is weak and have already slowed down the turbo because the air is travelling backwards. So closer to the tb the better. Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted February 16, 2006 Share Posted February 16, 2006 myplasticegg, Re-read zguy36's post. The pressure wave STARTS at the t/b because thats where the restriction is. It then travels back through the piping, through the intercooler, to the turbocharger. If you put it near the t/b you are not letting the wave travel as far. If you vent to atmosphere with an AFM system the engine thinks its getting air and its not so the engine runs a tad rich for that time when the BOV is venting. How fast can you change gears? Dave Quote Link to comment Share on other sites More sharing options...
violacleff Posted February 16, 2006 Share Posted February 16, 2006 Not that it really matters, but the dsm bov sounds horrific when vented. It is just fine when recirculated though. Not sure what Promax...however u spell it is talking about. Function is important first and foremost, but just in case you were tempted to vent it, don't do it. It is an absolutely awful sound. Quote Link to comment Share on other sites More sharing options...
nienberg.11 Posted February 16, 2006 Share Posted February 16, 2006 YES YOU NEED ONE. Its bad to run stock boost without a BOV let alone 15psi....If you are running an afm you need to recirculate the bov into your intake tract....If you do not recirculate it and let it vent to the atmosphere then your car will run really rich when you let off the throttle. If you are coming to a stop it might even stall. I totally agree with Thumper on his first point. You need BOV. However, I'm running a 2G Eclipse BOV vented to the atmosphere and the car runs fine. The RPM's don't go below idle speed even after running hard and coming to a stop. There is of course some richness associated with this, but take it from someone who is running it this way, it's played up to be more of an issue than it is in reality. Oh btw, the 2G bov is a poorly made piece of equipment, like someone mentioned earlier. It doesn't seal properly under vacuum. Viola, I don't know if the 2G fits into your category of horrific sounding BOVs, but as a matter of opinion I think mine sounds pretty good if you're not looking for something to make a high pitched attention grabbing shriek every time you let off the gas. In any case, I'm going to be replacing mine with something else when I do my IC install, and I'm thinking I'll have a hard time finding a better quality BOV that isn't obnoxious. Quote Link to comment Share on other sites More sharing options...
big-phil Posted February 17, 2006 Author Share Posted February 17, 2006 I might try venting it just to see what it does, and if it is running rich, I'll dump it back in after the AFM. Quote Link to comment Share on other sites More sharing options...
zguy36 Posted February 17, 2006 Share Posted February 17, 2006 I had mine dump on the old stock setup and there weren't any driveability issues. It did make it more prone to shoot fire between shifts too. I didn't realize how rich it was actually going though till I bought the wideband. 9:1 between shifts.... Not really a big issue, just a little added fuel cost Quote Link to comment Share on other sites More sharing options...
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