blow-off valve...

I heard this talon on the street a couple days ago when I was driving to work. I heard a vroooooommmmm psshhhhhhhhh!. So when he was next to me i shouted out the window what kind of turbo/blow off valve he had in there. He said it was the 14b with a stock bov. I was like "how you make it sound like that then?" he mentioned something about drilling a bigger hole in the nipple or diaphragm or something on the bov aND that makes it louder. He said it doesnt sacrifice accel or idle roughly or anything. The only way I could think of to make my car sound like that was to take off the return hose that goes from the bov to the turbo. When I did that the car idled roughly and stalled. Anyone know what this guy meant by drilling that hole, and is this the best way to make it sound loud? Could someone explain how to do this?

by the way it was a 1g talon

if you vent your stock 1G bov and look into it while its idling you can see its open letting the seep out, this is what give the crappy idle

sounds like that car did the high boost mod http://www.thedodgegarage.com/turbo_bov_mod.html

I have done extensive work with BOVs on DSMs, and I cant for the life of me figure out what the hell he is talking about. Unless he gave a weak ass description of what is known as the "Gus Mod." But even with that, the only way to get a 1g BOV to run decently well vented is with a large check valve on the outlet, and some creative use of spring rates. I did it for years, and its no simple matter. ;) But it can be done. If he said he had a VPC or MAFt in blow through mode I would believe it. Another thing to note, 1g BOVs are not very loud when vented. Conversly, the loudest BOV out there by far is the RFL, which comes with its own bag of problems, but runs pretty well vented with the right preload on it. Just some random info ;)

I am new to the dsm game but my 1 gen is pretty loud to all you have to do is vent into the atomsphere. remove the tube going from the intake to the bov block it off an there you go. Or he was bulls&^tn.

I am new to the dsm game but my 1 gen is pretty loud to all you have to do is vent into the atomsphere. remove the tube going from the intake to the bov block it off an there you go. Or he was bulls&^tn.


I dont know about the 1st gen bov. But my greddy type s vented into the atmoshere is LAH(loud as hell).. Scared the sh..well crap out of a few un-suspecting pedestrians and cars to my right. Love it when you hear someone reving at a light or fellow racer with there window down. Sometimes pull up to the drivers window and let 1 GOOD bov POP out. Heads instantly turn!! That has to be the greatest feeling other than walking some ol cocky mustang owner with import killer on the back.

i have a Greddy type S BOV on my 97 GST and its really loud also. I was wondering how you make it blow of at a light. I just got the car and im new to the turbo thing. When i shift it does it but how do you do it at a stand still. Also would setting that to the loudest (all the way open?) setting make the engine idle funny or is that the HKS cam shaft or AEM cams...thanx for you help im trying to learn as much about my car as possible!!!

i have a Greddy type S BOV on my 97 GST and its really loud also. I was wondering how you make it blow of at a light. I just got the car and im new to the turbo thing. When i shift it does it but how do you do it at a stand still. Also would setting that to the loudest (all the way open?) setting make the engine idle funny or is that the HKS cam shaft or AEM cams...thanx for you help im trying to learn as much about my car as possible!!!


I actually went playing with my bov today at lunch.. if you set your bov setting to softest its the loudest setting, and hardest is making less noise to none at all. And I vented my bov into the atmosphere again and pugged the intake. Thus again car running sluggish and nitice a slight loss of power and idle rpm. So best to leave it venting into the intake and have the needle about half way in. may lean alittle towards the soft setting to get alittle bita noise thats fine. But when I vented into the atmosphere I did a power loss check. Reved the engine and at 5000rpm air started leaking out of the bov. And making your bov go off like shifting at a light. Just hold in the clutch alittle and let out abit as you step on the gas. Itll let off the sound like you were shifting.. these are all based on my car and what ive found. car and drivers may vary..

just put it in neutral and rev it up

the car hates ventin like that by the way
thats why u have crappy idle, and stall out at times

I heard this talon on the street a couple days ago when I was driving to work. I heard a vroooooommmmm psshhhhhhhhh!. So when he was next to me i shouted out the window what kind of turbo/blow off valve he had in there. He said it was the 14b with a stock bov. I was like "how you make it sound like that then?" he mentioned something about drilling a bigger hole in the nipple or diaphragm or something on the bov aND that makes it louder. He said it doesnt sacrifice accel or idle roughly or anything. The only way I could think of to make my car sound like that was to take off the return hose that goes from the bov to the turbo. When I did that the car idled roughly and stalled. Anyone know what this guy meant by drilling that hole, and is this the best way to make it sound loud? Could someone explain how to do this?


Forge Motor sports makes a nice billet aluminum Diverter Valve. To me it's plenty loud and idles right on the spot. It uses the stock fitting so no need to mod your stock upper piping (if you have stock upper pipe). And for 14 bucks they will ship you a spring set to adjust the tension on the valve. Comes apart with an Allen wrench. Best of all the black anodized looks like a stock DV to even some hard core DSM fans. But this is the same company that Pruven Performance uses for there BOV or DV needs on there 11 second Evo8. I'm sure they have one for both second and first gen DSM cars

How much louder with boost will a BOV or DV get? Im running alittle over stock PSI and it sounds nice and crisp even on the freeway. It about 20 pounds will this thing just blow like a damn train whistle?

Our cars do not run properly with a vented BOV, even if you get it to idle right (thats the easy part). You need a VPC (MAP sensor conversion) or a MAFT (hotwire sensor convresion) to do it properly. I ran vented for years, but it has some pretty substantial drawbacks if you are trying to make power. BOVs arent there to make noise, they are there to protect the turbo and reduce lag.

I can get a full blow off while the car isnt moving. Just floor it, it hits the launch rev limiter (stutter box), and it builds 10-15 psi, so it makes quite a ruckus when i let off. ;) My turbo is arge enough that just free reving in nuetral wont get much at all out of the BOV. Its just too big to spool without a load. But the 14b/16g would do it all day.

so unless I get ahold of an aftermarket bov and do whatever tuning to make it not idle crappy, im not gonna have that bov sound. well....looks like ill be going back to my original idea of a quiet sleeper that blows the paint off anything. crap!

I personally run a Diverter valve. And i know most street (dsm) cars need to run back to the turbo. I was just asking how much louder can i exspect this thing to get as i push my PSI up into the 20psig range

The DV unit from forge is priced right. About 150 with shipping. No big loss of cash really. And on my car this thing made the biggest single increase on my butt dyno over the intake and exhaust

I use BOV to cover all types of valves. I understand the concept of calling it a diverter valve, but thats a term rarely used by DSMers, and I'll bet you drive an VW or Audi :) BOVs will get a little louder with more boost. But the best way to make it louder is to add a solid metal intake pipe to replace the convoluted snorkel. And get an open element filter like the ever popular K&N kit. The factor stuff was all put there not only to filter and channel air, but to silence the turbo and BOV. Also, on a 2g, doing the dumptube hack (www.vfaq.com) will often make it louder. And I dont consider this a rice mod since everything I mentioned above is also done to improve power. With a hard metal pipe and a K&N you can expect 20 HP gain on a mildly modded car. ;) Spending 250 bucks on a ricer valve will make it loud, but it wont add any power (over a 1g BOV that is, 2g one obviously leaks). Hope that helps.

I use the term DV not to confuse anyone. Forge MS makes two models for the Evo8 and Eclipse. One is a dedicated BOV and the other is a dedicated DV. The company is based in Europe, which could explain the terms used

Is the Forge Motor Diverter Valve is an add-on to the BOV? I currently have the Greddy Type S BOV but it doesnt sound loud. It only makes a whistle sound instead of a loud ppsshhh sound. I would like to buy the diverter valve if it connects directly onto the bov to create louder sound.

No, it's a BOV or DV in it's own

for the type S, as far as i know, you need to adjust it a bit to find the right spot of ppppshhhhh. too tight might not be loud enough while too soft might sound too soft. play around with it then decide. it's different for each car too. mine sounds very loud and sexy! :P.

Is the Forge Motor Diverter Valve is an add-on to the BOV? I currently have the Greddy Type S BOV but it doesnt sound loud. It only makes a whistle sound instead of a loud ppsshhh sound. I would like to buy the diverter valve if it connects directly onto the bov to create louder sound.
This is why I don't like overcomplicating terminology that could be simplified.