Sacker90

My bov isn't very loud compared to other 3rd gens running the same amount of boost. My turbos are setup non-seq, and I've checked all vaccuum hoses and they are all connected w/o any rips or tears, I'm also getting 14 vaccuum at idle and 20 in gear. I am NOT trying to be ricey or whatever you all will probably say, just wondering why and hoping it wouldnt hurt the turbos with the pressure not being released as much. thanks

TT_Rex_7

This could be for a number of reasons. First of all, what BOV do you have, and do your friends have the same BOV?

-Alex

Sacker90

i have turboxs, friends have stock....

TT_Rex_7

Well all BOV's sound diffrent, so you really can't compare 2 diffrent BOV's.

That being said, are you having compressor surge? If not, then the BOV is doing it's job, and you have nothing to worry about!

-Alex

Sacker90

We ll i can put my stock one on also and still not be as loud as theirs, i dont think i am...

1QWIK7

iTrader: (33)

let me chime in because im in the same situation as you

i am also non seq with the turboxs RFL bov..when you go wot, you still cant hear the bov?

that happened to me when i first got my turboxs, i ghetto rigged it just so i can test drive it and hear it..when i would go wot, i felt there was no power, i glanced at the boost gauge and it wouldnt go into psi..i knew something was wrong because of that and because i didnt hear the bov not even once..i got home and checked and i noticed when i closed the hood, it would pinch the vaccum hose that goes from it to the uim..i re-routed it under the intake pipe so it wont pinch and then it worked..

let me also ask how did you install it?

because for some reason i hear my bov more when i place the horn facing up towards the hood, rather than to the side or to the bottom..i would also check for spring rating, your bov came with metal washers correct? i would adjust it to your need..

also i would check for other vacuum leaks because your vacuum readings seem off (well unless my car is not normal)

because i would get 18in at idle..

Sacker90

Well catching enough boost(more than i should), and i've checked all the vacuum hoses and all seem fine. Do you back the nut on the bov in or out for lower boost?

RX7Wishing

easy way to see if the BOV is doing its job is..


1.) listen for compressor surge
2.) Rig your Boost gauge up to a nippe (if youhave one) that is before the TB/after turbos. You should see boost drop rapidly after you left off the gas.
3.) Pop the hood. rev the motor while your hand is over the BOV exit. You should feel air exiting rapidly. Should also be somewhat audible.

Im still using the stock BOV on the seq system and it is very audible.

kuning

Are there going to be any effect having no-bov?

CantGoStraight

If you have no BOV you will kill the spool of the turbos, can damage some turbo components.

TT_Rex_7

Kill the spool of the turbo(s)? Wtf are you talking about?

If you don't run a BOV, your turbo will be more responsive after you shift, because it won't release the pressure (boost). There are several serious drag guys that don't run a BOV. For example, Ralph of Xcessive Motorsports doesn't run a BOV on his drag Supra for this reason. However, it will shorten the life of your turbo. If it's BB, it'll last longer without a BOV, than a journal bearing turbo(s). For street applications, run a BOV!!

-Alex

TT_Rex_7

You tighten the nut when your running higher boost #'s. You wan't to make sure it's loose enough so you don't have compressor surge, but tight enough so it doesn't leak. That's just something you have to play by ear. I'd start off by having it loose, if it's leaking boost, then tighten it until it stops leaking, but listen to make sure you don't start having compressor surge. If you can't find a happy medium, call the manufacturer, and tell them your problem. They should be able to send you a better spring for your application. A diffrent spring won't make it louder, it'll only help you find a better medium between it leaking and having compressor surge. If your BOV isn't experiencing these two problems, then your BOV is just fine.

-Alex

Sacker90

how much vacuum should I have at idle? I just have 14...

maxcooper

Comparing vacuum numbers doesn't work very well. It is affected by too many things (idle RPM, gauge accuracy, porting, idle mixture, altitude, ...) to be very comparable over the internet. That said, 14 in Hg is on the low end of normal by most accounts. But my new engine idles at 12-13 inHg and is just fine (big street port, 1-piece apex seals, rich idle, gauge of dubious accuracy ).

-Max

CantGoStraight

Maybe I'm missing something here but if you let off the gas (accelerator) the throttle plates close some what or even completely, the turbo's are still hauling *** so where is all this pressure the turbos are making supposed to go ? ? ? I agree that if your just shifting to another gear and staying WOT then the BOV has less effect but when your letting off the throttle after a WOT rn and have no blow off valve you can damge the shaft on the turbo's when the throttle plates are closed and the turbo's are still spinning. Maybe this is WTF I'm talking about. The noise he's talking about is the pressure in the intake that would be putting this pressure on the throttle paltes and turbine wheels when let off of or closed........am I still missing something here is there only one way to look at this ? ? ? ?

TT_Rex_7

The pressure goes back towards the compressor wheel, and trys to spin it backwards! This is called compressor surge.

I never said it wouldn't damage the turbo. Over time, it will damage the turbo, how long that takes depends on what turbo it is, and if it's BB or journal bearing. A BB turbo will last longer than a Journal bearing, when a BOV isn't being used. Obvouisly, that only holds true if both turbos are the same, just diffrent bearings being used. This is WTF i'm talking about!

When I asked WTF you was talking about, I was referring to your comment that not running a BOV will kill your spool. A BOV has no effect on how fast/slow your turbo will spool in 1st gear, but when you don't run a BOV, the boost will stay up during the shift from 1st to 2nd, 2nd to 3rd, etc. etc.

Now, if your BOV leaking, it will effect spool up, since you can't build pressure.

The noise from a BOV is caused by the pressure being released from the intercooler piping. However, you can also hear compressor surge, which makes a "weird" noise, that starts off loud, and gets quiter. Now, if he isn't experiencing compressure surge, and it's not leaking, then the BOV is doing its job, and there's nothing to worry about. Every BOV sounds diffrent, some louder, some quiter.

-Alex

CantGoStraight

So since he's running stock turbo's was there any doubt which type we were talking about ? ? ? Since he's not racing is it unecessary that he have a blow off valve. His concern was that he doesn't seem to have as much blow off as other cars like his with similar BOV. I've noticed the same thing with my car compared to a friends car. Very noticable in the charge relief valve(the one that vents the secondary turbo untill 4500) maybe this is the one he's talking about not making as much noise as everyone else's. My friends sounds like a damn compressor with the hose off till it closes. My turbo's are tired & need replacing and my friend is running the Pettit High flows in excellant shape, so maybe it's not the blow off he's talking about who knows....anyway it was my understanding the BOV if it didn't work killed the turbo's spool as it backed the air up between the throttle plates and compressor wheel.