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Engine Specific Info and Questions => IDI Engine => Topic started by: Darkness_is_spreading on July 24, 2008, 09:38:41 am
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I am wondering if I should connect a BOV to my 1.9 TD, I will be running my wastegate at around 20-22 psi and am worried that after loading the turbo up to 22 psi and letting off, the wastegate will let off but I will still have a fair amount of pressure in my intake and will have compressor surge.....
If I tie the wastegate line into the BOV I could have them trigger at the same time Hypothetically and thus eliminate any surging....
What do you guys think ?
I am trying to protect my built Hybrid turbo from early death, so I want to make sure every avenue is explored....
I will also be running a seperate Thermostatic Controlled Oil Cooler, to help keep oil temps down because the turbos like to heat up our oil.
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they have one in stock form, set to open at 0,7Bar
I see no problem in fitting one to open at say 25PSI, a few PSI more than your maximum boost, and a electric valve so it can only open when you let off the throttle.
if I were you, I would check first if it surges (a electric pressure switch set for 25+PSI and a buzzer/light) then deal with it.
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I've been running well over 20 PSI daily, and have yet to hear any comprossor surge. Its a rock stock K24 with the waste gate vented to atmosphere.
The only downside I've had is spitting off the trailling edge of one turbine blade.
Have you heard any compressor stalls?
You have the k24/k26 hybrid right?
Hows it going? I'm planning on doing the same soon, got a k26 sitting in my office.
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Alright so If I set the wastegate to open at 22 PSI I should be able to runthe turbo without fear of generating compressor surge......
I believe compressor surge occurs when the waste gate is locked down ( or wastegate line plugged )and is not allowed to open, thus having the ability to hit 30 PSI
What about the stock BOV the connects to the intake manifold, is that not the same priciple and must work in unicen with the wastegate to balaced out the boost between the exhust and intake.
We disable these items ( Broom stick mod and Wastegate line clamp) and we are disabling any safety of overboosting/compressor surge......
So if we adjust the wastgate to open later, and tie the wastegate line to a BOV we can have them make the same boost as before and have a safety net to protect from destruction......
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I had a k24 on a 1.6L making 35psi with nitrous. No surge. BOV's don't belong here.
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I had a k24 on a 1.6L making 35psi with nitrous. No surge. BOV's don't belong here.
Aw, but they sound so cool... 8) :wink:
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I had a k24 on a 1.6L making 35psi with nitrous. No surge. BOV's don't belong here.
Aw, but they sound so cool... 8) :wink:
No prob... get one of these... much simpler:
http://www.sunamiturbo.com/
(Nope, today is not April Fools Day) ;-)
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JHMFC!
it's crazy the junk some people will put on their cars.
I can tell you, my abovementioned K24, with a gated boost controller let out a hair raising wail every time I let off, even if only part throttle at mid rpm.
2.5" straight through exhaust, sounded like
BYYYOOOOOOOOOOOooooooo!!!
People who obviously had no interest in car stuff (women pushing baby carriages etc) turned to see what it was making this sound.
If you want cool sounds from your turbo car, skip the stupidity and give it a big exhaust!
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Dr Diesel is right about people looking around. I know a lot of people look around when I'm driving the Silverado with the Duramax and pull away from a stop. The turbo spooling is so loud since the turbo is on TOP of the engine and not buried down in the engine compartment that it sounds just like an 18-wheeler right next to you.
As libbybapa says, BOVs are for when the throttle plate shuts and you're still making +20PSI it will blow off pressure to keep the turbo from killing itself or blowing off any of your intake hoses.
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As libbybapa says, BOVs are for when the throttle plate shuts and you're still making +20PSI it will blow off pressure to keep the turbo from killing itself or blowing off any of your intake hoses.
I assume everyone here knows that Diesels dont have Throttle plates and therefore they never slap shut, and therefore diesels dont need BOV's.
The only reason I make this comment is because some Newbie might read this in the future and think that the above comment might mean that "BOV's are needed when the throttle plate shuts".
Obviously I'm stating the obvious. :roll: :o :D
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ok so what happens then when going from full boost @ 4500 rpm (25PSI) to an idle? Is the engine still processing that much air? No. What happens to all that air? It gets stopped up and pressurizes the intake the wrong way. My car makes a fantastic warbling noise under these conditions, and I too am worried about shaft snappage.
Any other ideas? I dont like the idea of a switch that opens the valve on idle position because some of us let off the throttle while shifting to another gear. Not completely of course during accel but completely during decel. Even a DV would be better to keep performance up.
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I totally understand the difference between the gasser need for a BOV and all that. But, the pump slows down to idle after letting off the throttle. Also, with the pump causing the engine to return to idle, doesnt that mean that the valves and pistons slow down?
As we all know, the engine is essentially a pump within itself. So if we slow the pump down then we are processing less air, no? Exhaust and intake alike.
The reason I am interested in this is because I believe I am getting a pretty fair amount of surge after letting off the throttle. Example, 1st gear pull to get to second, then WOT up to 4500 rpm and then let off the throttle. Hence the warbling noise. So if pressure could be vented somehow that might alleviate stress on the turbo. I plan on using a gt25 on the next engine and I dont it to break the shaft. Especially @ 30+psi.
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I have personally installed and test drove dodge diesel trucks with BOV's and they do make it easier on the turbo(s).I don't see any down sides to one being installed.The ones I've installed are from BD power and are called "Turbo Guard".I don't think that there is a real need for one when pushing 22 psi however.These devices are only really hepful for turbo(s) on diesel engines that produce say 35-40+psi.
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yes, however, take into consideration the size of the turbo on the Dodge vs. the little tiny turbos that we have on the VWs.
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As libbybapa says, BOVs are for when the throttle plate shuts and you're still making +20PSI it will blow off pressure to keep the turbo from killing itself or blowing off any of your intake hoses.
I assume everyone here knows that Diesels dont have Throttle plates and therefore they never slap shut, and therefore diesels dont need them.
The only reason I make this comment is because some Newbie might read this in the future and think that the above comment might mean that "BOV's are needed when the throttle plate shuts".
Obviously I'm stating the obvious. :roll: :o :D
I would hope that someone who owns a diesel would understand that they don't have a throttle plate and all power is controlled by amount of fuel injected, but maybe I'm wrong :|
Maybe I should have stated that diesels don't have throttle plates just to be more clear.
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I have had several people that are decent mechanics yet have 0 experiance with diesels ask how the engine controls its speed. Where the throttle blades are.
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throttle blades eh? :lol:
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Ok so we have gotten some were here, I'm gonna go with a BOV, and then control the pressure that leads to that BOV with T fitting off of LDA line. Have in NO or NC (Normally open Normally Closed) and see how that affects the performance...... Plus I get a wicked sound
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utterly pointless in my view, but, as someone else said: its your wallet.
I would do it if I had the parts around and time to kill, as a joke, like i did this time:
:lol: :lol: :lol: :lol:
(http://naotefiques.no.sapo.pt/DSC003.JPG)
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it's all about the wicked sound. Just like putting a "BOV" on a G60 engine. Utterly useless.
I doubt you'd even get much of a sound, at least, nothing like a gas engine.
Like Libbypapa said, at high RPM, under full boost when you shift, the engine's still at 5500 when you let off the pedal. It's still drawing 300cfm (or what have you) of air, which certainly doesn't pose a restriction to the output of a turbo that has suddenly found itself without any motive force on the exhaust side.
Probably wouldn't even hear it over the diesel clatter.
Maybe you could rig it up so the BOV's outlet pipe runs to a bullhorn carefully duct-taped to the roof. You could even set it up with relays and switches so that the bullhorn only triggers on only above 3000rpm when the throttle is at idle.
Battery life would increase, and you wouldn't spend most of the time amplifying the wind noise buffeting the bullhorn's mic.
Also, I'd probably mount it facing rearwards for better aerodynamics.
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I totally understand the difference between the gasser need for a BOV and all that. But, the pump slows down to idle after letting off the throttle. Also, with the pump causing the engine to return to idle, doesnt that mean that the valves and pistons slow down?
As we all know, the engine is essentially a pump within itself. So if we slow the pump down then we are processing less air, no? Exhaust and intake alike.
The reason I am interested in this is because I believe I am getting a pretty fair amount of surge after letting off the throttle. Example, 1st gear pull to get to second, then WOT up to 4500 rpm and then let off the throttle. Hence the warbling noise. So if pressure could be vented somehow that might alleviate stress on the turbo. I plan on using a gt25 on the next engine and I dont it to break the shaft. Especially @ 30+psi.
The engine slows down more slowly that the turbo. There is allot of rotating mass in the engine, so RPM doesn't plumit. As a result, I suspect the boost falls faster then engine RPM. The engine just pumps the 'excess' boost right through. No harm, no fowl. If you leave the engine in gear, it slows down even slower.
I'm haveing a hard time correlating 'warble' to a compressor stall. Compressor stalls tend to make sudden sounds like repeated thump or wump sounds.
I had a K24, that I was running just under 30 PSI, lose a section of a trailing edge of one turbine blade. It made all kinds of bizzar noises above ten PSI after it crapped the blade piece out of the tail pipe. I actually heard the piece of blade go rattling down the pipe, so I was able to mark the difference in sounds after word. It still made boost, but it also made some really strange noise too, and warbling could have been one of them.
You may want to look at your turbine blades and see if everything is OK in there.
Here is the photos of the blade failure:
http://www.vwdiesel.net/phpBB/viewtopic.php?t=14895&highlight=
This is a turbo that lived well above 20 PSI for three years. It even had new journal and thrust bearings. The shaft didn't snap, the compressore didn't throw a blade, it never had a compressore stall, and it only lost a small part on one blade.
I suspect the compressore stall problem on the big pick up trucks stems from turbos big enough to injest our tiny turbos, with significant rotating mass, making HUGH boost, on low RPM motors.
Oh, and they have huge "accumulators" (intercoolers) that may not bleed down as fast as out teeny manifolds.
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yes, however, take into consideration the size of the turbo on the Dodge vs. the little tiny turbos that we have on the VWs.
Its not really a question of turbo size but rarther Boost pressure.A BOV will only be useful for safe guarding certian turbo(s) when extreme boost pressures of at least 40+ psi are used.
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Ok so we have gotten some were here, I'm gonna go with a BOV, and then control the pressure that leads to that BOV with T fitting off of LDA line. Have in NO or NC (Normally open Normally Closed) and see how that affects the performance...... Plus I get a wicked sound
A BOV will not affect the performance in any shape or form.
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Wow for all the knowledge here there sure is allot of naivety.
The BOV would serve a purpose other than just making a cool sound (if you like that) it would allow the boost pressure that is built up in the charge piping a place to go in the event of a sudden peddle lift.
Believe it or not there is a drastic difference in pressure from the exhaust side to the intake side when this happens. Throttle blade or not it's there.
This is the reason turbo bark/ surge occurs and it will eat your turbo in time, experience speaking here not just throwing up on the key board.
The problem is getting a BOV that reacts fast enough to do any good, if it opens to late it's pointless if it doesn't close fast enough once again your defeating the reason for having it. the factory BOV has this problem, but then again it wasn't designed as a BOV it was designed as merely a safeguard against over-boost. Where we don't have throttle plates as well all know ;) it will be difficult to control it accordingly. there may not be enough pressure difference to get it to function as required.
I would like to have one on my system but I'm so tired of throwing parts at the damn thing I just don't see it happening. I'll just be nicer to the peddle and keep driving.
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The peak boost level does NOT occur after the pedal is lifted, but rather before. Therefore, how is it proposed that a BOV be actuated in order to routinely release the boost pressure when the accelerator is suddenly lifted?
On a gas engine, the intake pressure increases after the pedal is lifted, and so a BOV can simply be programmed to open when over-pressure occurs. Not so on a diesel...
Andrew
Exactly, this is a problem. Where we don't have a throttle plate making the damn thing work is a problematic.
Sure we can probably figure out a way to get it to open at say 25psi but when will it close and what if we are still in the gas (sorta speak) at 25 psi? It opes and we loose all the boost. :(
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The engine slows down more slowly that the turbo.
So I read this earlier today and decided to check to see if this is correct. I do not beleive it is. I ran my car at WOT in second gear a few times today and observed that the engine would return to idle and the boost pressure would remain at 6-7psi for about 3 seconds before returning to 0 on the gauge.
So, that in mind, the engine is obviously slowing down faster than the turbo. This test was done only at about 15psi as I didnt have a lot of road and I didnt want to take my eyes off of traffic on the freeway.
What say the group?
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Ok maybe I was not very clear in my posts. I totally agree that there is no need for a BOV on a regular setup.
Mine is not regular. I have not blown any turbos either. I am just looking at this thread and trying to participate with my own worries. My turbo was recently rebuilt and I dont really want to ruin it.
The turbo that I am using is the T3. I have the DV plugged and the wastegate disconnected. I see 25psi of boost regularly. I have an intercooler (albeit, its from an S4 with plastic ends tank but it does a decent job for now). Pump is tweaked (gov mod, fuel screw, boost pin, star wheel, etc).
I would also advocate for a DV over a BOV any day. Screw the noise, Im not concerned with that.
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Wow has this thread taken off. BOV crowd on the left with knives! Non-BOV crowd on the right with baseball bats! Lets have at it!
ok so what happens then when going from full boost @ 4500 rpm (25PSI) to an idle? Is the engine still processing that much air? No. What happens to all that air? It gets stopped up and pressurizes the intake the wrong way. My car makes a fantastic warbling noise under these conditions, and I too am worried about shaft snappage.
Are you really driving that way? That seems unusual. It would seem most people would accelerate through boost then back out at 4500 rpms, but the trans would still be in gear and the RPM's wouldn't drop to idle. The RPM's would be controlled by the gear you are in, and road speed. Obviously RPM's would drop gradually as the car slowed.
Sure if you Race your car up to 4500 then push in the clutch and coast for a while your car will drop back to idle. Certainly you dont race up to 4500 then push in the clutch, let the car dop to idle, then shift to 2nd, race up to 4500, let the car drop to idle ect, ect.
What makes boost? Fuel and RPM. when you snap that throttle closed, your taking away fuel very fast. And in most circumstances your road speed, clutch and trans will keep the rpm the same. Obviously road speed will slowly decrease with removal of throttle. But they dont drop to idle unless you push the clutch and let it drop to idle.
What controls air flow? RPM. And what controls RPM? Dont say the throttle! ROAD SPEED controls RPM! (taking into account gear ratio), That is, if you have a manual, and your clutch isn't slipping. Your RPM's, and therefore the volume of air you are injesting, will be controlled by your road speed.
So unless your racing your car up to 4500 then snapping the throttle closed while holding the clutch down or while staying in a lower gear, then I really dont think RPM change is causing a airflow restriction.
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it's all about the wicked sound. Just like putting a "BOV" on a G60 engine. Utterly useless.
Sorry for my ignorance. A G60 is a supercharged Corrado correct?
I'm trying to understand why a supercharged car wouldn't need a BOV. Is it because the boost is made "POST-THROTTLE-PLATE"??? So there's not Boost backing up against the throttle plate??
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Anyone who is snapping their throttles closed on their TD VW engines should be permanently banned from this forum... :P
Andrew
I'll second that notion!!!!
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The engine slows down more slowly that the turbo.
So I read this earlier today and decided to check to see if this is correct. I do not beleive it is. I ran my car at WOT in second gear a few times today and observed that the engine would return to idle and the boost pressure would remain at 6-7psi for about 3 seconds before returning to 0 on the gauge.
So, that in mind, the engine is obviously slowing down faster than the turbo. This test was done only at about 15psi as I didnt have a lot of road and I didnt want to take my eyes off of traffic on the freeway.
What say the group?
If you still have boost reading on your gauge at idle you have a kink in the boost hose or a restriction somewhere.
There will be no boost at idle not even for a second, it takes fuel to spool folks.. Nothing else will create boost.
That's what this dude says :)
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My suggestion for those after the pssssst: take all the time and energy and money you might spend on rigging up a vestigial BOV for our little turbos and donate it to charity... you'll get the same warm fuzzy "aren't I great" feeling, you'll arguably be just as attractive to the chicks (perhaps even more so, since you've demonstrated your sensitive side) and you'll actually be doing something useful. :roll:
But that's just *my* suggestion.... :wink:
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I agree Vince.
I would love to see someone make one that works and ot have it cost hundreds..
Till then I'll keep my closed system.
I would like to add however it's threads like this that get us thinking about ways to improve and progress..
Good stuff here :)
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You guys are missing the point. Yes, I drive my car like I stole it. Hence the reason why I dont want it to be broken. Hence the reason why I am even posting in this thread.
Yeah, I WOT frequently. Then there could be a stop light, or someone in front of me that is stopping or slowing down. Clutch in. Slow down. When coming to a stop, why would I leave it in gear? We drive these cars to get good mileage right? Leaving the car in gear reduces that mileage.
It seems to me like everyone reading my posts are either A. thinking I have been blowing up turbos, or B. should be driving like grandma.
I have not blown up any turbos (yet) and I most certainly dont drive like grandma. I beat the crap out of my car. Why? because I dont have millions of dollars for test equipment. I have my car. What do I do with this information? I apply it to working on other peoples cars.
Dont give me any crap about how I should be banned for running my car @ WOT and checking my numbers and sharing them here. Its obviously to get information. The same reason the rest of you are here.
zukgod: please reread my post. I assure you that I have ZERO kinks. The system is clean, no harsh bends or anything backyard going on. Remember, this is returning from full boost to clutch in for idle.
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it's all about the wicked sound. Just like putting a "BOV" on a G60 engine. Utterly useless.
Sorry for my ignorance. A G60 is a supercharged Corrado correct?
I'm trying to understand why a supercharged car wouldn't need a BOV. Is it because the boost is made "POST-THROTTLE-PLATE"??? So there's not Boost backing up against the throttle plate??
G60's (as do most supercharged cars) have a bypass valve which closes (give or take) inversely proportional to the opening of the throttle valve.
At part throttle settings, when boost isn't needed, the bypass valve is also partly open, allowing excess air to be diverted back to the supercharger's inlet. Effectively unloading the supercharger. Fuel economy and charger life is improved.
Some numbnuts thought it'd be cool to basically remove the bypass pipe running between the bypass valve and the s/c inlet. That way, after a mid-high rpm run, closing the throttle valve opened the bypass valve, and all the excess air hisses out making a sound similar to a gas turbo car's BOV.
Woopee.
The downside is that the abovementioned benefits are lost, plus when the car sits, there's a wide open hole for crap/bugs etc to enter the engine. A small filter would eliminate that issue, but not help any of the others.
Seems like a lot of BS for a 'cool sound'.
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To operate a BOV on a diesel you use can use boost pressure to open the valve.Use a micro switch to activate a solinoid valve which delivers boost pressure to the BOV.
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sorry, I guess I kinda went off there.
the only reason why I would think it would consume more fuel is that the engine would be making the pump run at a higher rpm than idle. Kinda like why the Lupo 3l only comes in automatic version to be able to keep the pump rpms down during deceleration.
One thing to note, my vanagon does not make the noise that my rocco makes after pushing in the clutch. I assume that is because the Vanagon has a K03 so it can spool down much faster than the T3.
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zukgod: please reread my post. I assure you that I have ZERO kinks. The system is clean, no harsh bends or anything backyard going on. Remember, this is returning from full boost to clutch in for idle.
I don't need to "reread your post I know what your saying. My point is there is NO way there is residual boost left in the system after your engine has returned to idle. You either have a restriction or a POS gauge that doesn't react fast enough.
It's a mater of simple physics sir. The boost is gone as you discontinued the fuel input..
It takes FUEL to SPOOL....
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Well, if we are talking about physics here. lets talk about inertia. I find it very hard to beleive that as soon as the engine has returned to idle, that the turbo is instantly responsive and returns to 0 boost. Especially when my gauge tells me otherwise. My gauge is a new Autometer and there are no kinks.
I find it very hard to beleive that the turbo (spinning at 30k rpm) returns to idle rpm instantly.
we can use a pinwheel as an example. If you blow on a pinwheel and get it to spin, the pinwheel does not come to an instant stop as soon as you are done blowing on it.
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Ok I guess you win.
I'm not going to argue with you about it.
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Im not trying to pick a fight, I just dont understand how the turbo returns from 30k rpm to say maybe 10k in the timespan of 1 second (about what it takes for the engine to return to idle).
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Im not trying to pick a fight, I just dont understand how the turbo returns from 30k rpm to say maybe 10k in the timespan of 1 second (about what it takes for the engine to return to idle).
The internal friction of a turbo is high, and in the case of our own turbos the inertia is very low. Very small compressors, very small turbines, combined with journal bearings (which are among the higher friction bearing variety) all combine to bring the speed of that turbo down very, very quickly.
The reason they spool up quickly, in turn, is because they have very low inertia.
Combine the sudden loss of exhaust pressure with the internal friction of the turbo and the bit of back pressure inherent in any compressor, the turbos spin down quite quickly.
Even the huge Holsets on our buses don't take more than a second to go from peak boost to no boost, and they're pushing 45+ PSI with nearly six times our own engines' flow rate.
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I find it very hard to beleive that the turbo (spinning at 30k rpm) returns to idle rpm instantly.
Try 100K RPM. That's the ball park RPM they spin at under full boost.
The boost on my TD rabbit drops like a rock when I take my foot off the go pedal. I specifically watched it yesterday while I was driving all over the state.
To even have a chance of haveing the engine wind down faster than the turbo, Id have to rev the greegree out of it under full load (third gear or higher), then push the clutch in and coast. But I still think the turbo will decel faster than the engine.
And I can't think of a normal driving scinario where I'd want to do that on a regular basis. And I drive 'em like I stole 'em too
The low rotating mass of the turbo will also help it decel faster than the engine, which has humungus rotating mass.
Try cleaning your boost gauge. There is some bizaar gak that lives in the crank case vent gasses. They tend to condense out when then have a chance to sit.
I have to clean mine out occasionly. (its due for a cleaning now) I stuff the stick nozzle thing that comes taped to the side of brake cleaner aerosole can, right up the kazoo of the boost gauge. A hoste of black goo cascades out. I also disconnect the line from the engine and back flush it too.
I like the fart sound the VDO gauges make when they're clean.
Oh, and for the record, I believe my turbine blade failure was a combination of metal fatigue, agrivated by spinnnig it too fast.
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One other thought... many many "boost gauge install kits" have a tee with a restriction build in... the restriction damps the small pulses in boost around 0 that cause the needle to buzz against the zero stop.
I bought one of these tees on purpose... the buzzing was driving me mad... and now the buzzing is gone, however, the trade-off is that the boost gauge doesn't drop quite as fast as it used to.
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My VDO gauge makes a buzz (fart) as it exhaustes the boost pressure when everything is clean.
I can tell there is gak in there as it doesn't make a sound.
It doesen't buzz at low boost either, just when the boost is dropping.
I like VDO as it matches whats in the car already.
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My VDO gauge makes a buzz (fart) as it exhaustes the boost pressure when everything is clean.
Maybe it ate too much saurkraut? :lol: :shock: :shock: :lol: :roll:
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My VDO gauge makes a buzz (fart) as it exhaustes the boost pressure when everything is clean.
Maybe it ate too much saurkraut? :lol: :shock: :shock: :lol: :roll:
That applies primaily to the driver. :wink:
Maybe a blow off valve is a good idea after all. :oops:
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My personal experience with a BOV on a TD is not a good one.
On my TD Vanagon I was running with the wastegate adjusted for boost above the BOV threshold (about 9-10 lb IIRC). Under normal around town circumstances it wasn't a problem, but when climbing a hill and really running it hard, the boost would overcome the BOV and I could hear pressurized air exiting the manifold through the BOV (the loud whoosh all you kids are after :P ).
It would do this in bursts if you held the pedal down. EGT's skyrocketed.
In a gasoline engine this is no big deal, a rich mixture never blew anybody's gasser up, diesel on the other hand :roll:
I theorize that as the pressure was being released, copious amounts of fuel were still be injected, the turbo was still making boost & demanding fuel from the injection pump, but the air wasn't present in the combustion chamber because it was bleeding off, which severely richened the mixture.
After that trial, I nixed the BOV and relied singly on the wastegate to regulate boost pressure. I based my settings on maximum attainable EGT of 1300 on a WOT lug run to the top of this huge hill by my house.
All one really needs for safe functionality is a boost controller valve, a boost guage and a wastegate.
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My VDO gauge makes a buzz (fart) as it exhaustes the boost pressure when everything is clean.
Maybe it ate too much saurkraut? :lol: :shock: :shock: :lol: :roll:
That applies primaily to the driver. :wink:
Maybe a blow off valve is a good idea after all. :oops:
Natural gas enrichment under full load? :D
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many many "boost gauge install kits" have a tee with a restriction build in... the restriction damps the small pulses in boost around 0 that cause the needle to buzz against the zero stop.
And there was I stuffing some cigarette end in the gauge tube. 8)
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All one really needs for safe functionality is a boost controller valve, a boost guage and a wastegate.
And a............ pyrometer.
Or am I just wanting more gauges, to pimp my ride, cuz its cool?
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No. A pyro is #1 gauge in my book. Butt dyno will tell you if you are getting too much or too little boost.
FWIW, my interest in the BOV part of this thread was not regarding the OEM DV. That things a joke. Mine is replaced with a billet unit.
Also, for record I dont care about noise. Well there is that warbling which has me concerned...
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well anyone that uses a BOV valve in a diesel is pretty much missing the point. Intake pressure doesn't matter at all! after you lift the throttle up fuel supply stops (mostly) but the intake valves are still gonna open. Next one that does it eats up all the air and so on.. there is no limiting factor in air intake in a diesel throttle up or down. The real issue is are you properly using all 25psi? pressure alone means almost squat. Volume means everything. stock intakes on vw diesels have a nice restriction opening up to four ports. imagine sucking with 25 psi on a small straw compared to a big one. too much boost without proper porting can do what happens to me. blow out intake seals.
This is from years at John Deere with turbos the size of your engine.
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As libbybapa says, BOVs are for when the throttle plate shuts and you're still making +20PSI it will blow off pressure to keep the turbo from killing itself or blowing off any of your intake hoses.
I assume everyone here knows that Diesels dont have Throttle plates and therefore they never slap shut, and therefore diesels dont need BOV's.
The only reason I make this comment is because some Newbie might read this in the future and think that the above comment might mean that "BOV's are needed when the throttle plate shuts".
Obviously I'm stating the obvious. :roll: :o :D
Sorry to be the barer of bad news guys, but the world is changing. The OEM's are begining to put throttle plates in diesel engines as part of their scheme to reduce emissions.
Has anyone laid hands on the 2009 TDI to know if they have gone to a throttle too ?
http://www.dieselpowermag.com/features/0710dp_2007_dodge_ram_3500_67l_cummins_bluetec/index.html
http://www.whnet.com/4x4/diesel_2.html
http://www3.jetro.go.jp/ttpp/EAN.CR06_EAN?id=1101349&corner_id=999
http://sciencelinks.jp/j-east/article/200521/000020052105A0846836.php
http://www.mitsubishi-fuso.com/en/sales_service/special/2004/download/4M42T_engine.pdf
http://www.freepatentsonline.com/6823660.html
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all the PD's I've seen have a butterfly valve. NOT used as a throttle.
it opens as soon as you turn the key (before the starter is engaged the valve has to be fully opened) and it closes when shutting off, to suppress the shutdown vibrations and when the ecu detects that the engine is running away.
thats a very good feature BTW
high HP setups swap it out for a free-flowing pipe.
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Well there is that warbling which has me concerned...
If its warbling that your worried about, a BOV is not the answer.
Compressor stalls are thumps, wumps, or buzzes.
My turbo warbled and made all kinds of weird harmonics when it crapped a blade off the turbine.
Check your turbine wheel for missing or bent turbine blades.
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turbo is rebuilt. warbling happened when it was installed. previous turbo did the same thing. both were T3 units.
previous turbo did not fail, it was just that the rebuilt turbo fell into my lap and I preferred a rebuilt unit over a used one.