OE Dump Valve....

[DIXIE]

okay so...

http://i86.photobucket.com/albums/k104/Hott_For_You/dumpvalve2.jpg

is this the same as on my ah sri t ??

if so, im going to be blocking it up tomorrow morning to see if i can get this thing dosing.. can anyone tell me for sure if the turbo/dv setups between the sri and the vxr are the same ??

thx

dix
:)

[CAL.16V]

if you want to block off the existing dump valve take teh 4 allen key bolts out and take the black cover off in the picture... then silicone some washers onto the cover and put it back on... the you can take the vacume piping and use it for your other bov.. i'm assuming your replacing it with another one as not having any is bad

[DIXIE]

no.. not having any is GOOD

ffs

bovs are for girls

[poita]

pat its all about the dose

[xplosv57]

Replacing it with a Bailey's dump valve makes it dose too, heard an SRi-T with one and sounded nuts!!!

But block it off and let us know how you go, better be a Youtube video of it!!!!

[DIXIE]

yeah i did it.. its pretty gangsta :)

[xplosv57]

Worthless without video!!!!!!!!!! I wanna see this thing!!!

[CAL.16V]

it might sound 'cool' but its not good for your car is what i meant...

if you want sound just leave it as it is and get a pod filter

[USC]

everyone..take a note not to buy his car if he is ever selling...:p

[blueraven]

no blow off valve/wategate control will kill your turbo nice and fast :)


fully sik eh?

[OPC]

it might sound 'cool' but its not good for your car is what i meant...

if you want sound just leave it as it is and get a pod filter


no blow off valve/wategate control will kill your turbo nice and fast :)


fully sik eh?

listen to these dudes... gangsta

[MAD-16V]

Enjoy your compressor surge :(

[DIXIE]

you people are wack.

evidence supporting "comp surge kills turbos" please?

[blueraven]

BWAHAHAHAHAHAHAHA.

go to www.astraownersclub.com and see how many people with astra's/vxr's that have blown their turbos ;)


its a well known fact that turbo flutter increases the pressure on the bearings inside the turbo by huge amounts amounts (the sound you hear is the turbo cavatating because its trying to force more pressure into the pipes than the air will allow, hence the impeller wheel spins under pressure = bad for bearings.)

but by all means, 'dose' it up, we know nothing.

I have a spare turbo sitting here for when you need it :) $500.

[R3N]

Ok before things get nasty...

DIXIE as far as you know VLs cope with the flutter or 'dose' fine, but VLs do not represent all turbo cars, even S15 and Skyline owners avoid flutter unless they're running a stronger turbo, bottom line is that its bad for your turbo, just depends if the turbo can handle it.

[DIXIE]

dose for a day

or bov for a lifetime?

i think i know which one i'll choose.

[poita]

dose for a day, FTW!

[Wraith]

listen to these dudes... gangsta

+1

As I've already mentioned in the other thread, it's not worth wrecking your mechanicals just for a bit of sound :rolleyes:

Get rid of your airbox and put a pod on it and enjoy it that way ;)

[USC]

guys...why are you so concerned about his car?? let him do whatever he wants...he going to give some more business to holden in the near future....:D

[SSS_Hoon]

LoL this thread is funny.

Its like that other one i read awhile back on that forum about those things with those ppl on it.

1 person over in that country that has those animals with the funny hair, said it was bad for you if u ate apples so everyone stopped eating apple wierd hey.


HAHAHAHAHAHAHAHAHAHA


I will say there is argument for both sides of this story though it does depend upon the turbo, but it does sound fully hecktik yo....

When your lapping the streets and ya see some fully hot chica's on the footpath and you does em and they get all wet n stuff for ya its so mad mate.




SSS_Hoon

[xplosv57]

Oh well, if it breaks, it breaks!! Better excuse for him to get a bigger turbo and go nuts!!!!

So what did you use to block the BOV off and i still wanna see a video of it, PM one if you can, cheers!!!!

[rusole21]

Hahaha your awesome!!!:dance:

[rusole21]

http://img261.imageshack.us/img261/4351/newgaugeuh9.jpg

Enjoy Habib

[poita]

just make sure you've got one of these in the other hand wen ur doseing!

http://pub.tv2.no/multimedia/na/archive/00194/kebab__mat_194026s.jpg

[Huhness]

just make sure you've got one of these in the other hand wen ur doseing!

http://pub.tv2.no/multimedia/na/archive/00194/kebab__mat_194026s.jpg
I'm hungry....

[GreyRex]

What effect would a pod filter have on the car?? I'm not really an expert, so sorry for the question. Just a bit of extra noise internally, and that's it?? I reckon the engine in the Turbo's are a bit a quiet, so i mite consider it:)

[SSS_Hoon]

a pod filter can also get you a defect notice unless they are fully enclosed, but then again so can a BOV if it vents to the atmosphere.

The baily ones seem to work well for the SRiT's MR T has one and its seems to work fine and is not too loud and over the top.

SSS_Hoon

[R3N]

cmon guys... don't make me have to clean up the mess

[CNBLU]

pod filter not only adds a nice sound to the car but its also an increase in performance. yeh sure if its not inclosed properly you have the chance of breathing in hot engine air and it is classed as defective but what isnt these days??

ive got an apexi pod filter on mine and havnt looked back, the sound is just incredible:D

[xplosv57]

Every modification mo matter how big or small needs to be engineered these days, but hardly anyone does it!!! I mean who is gonna go to all the trouble to pay for an engineers cert when the modification didn't even cost 1/4 of what the engineers costs???

P.S. All you dose haters suck it up, you wish you could dose too!!!!

[Wraith]

pod filter not only adds a nice sound to the car but its also an increase in performance. yeh sure if its not inclosed properly you have the chance of breathing in hot engine air and it is classed as defective but what isnt these days??

ive got an apexi pod filter on mine and havnt looked back, the sound is just incredible:D

Next time I'm down there in Crannie, you'll have to give me a listen Gav. ;)

I like the suction 'screetch' I get with the stock induction setup ever since I've flashed it with Waynes 'aggro' re-map, would like to compare that to your pod set up, although I'd want an enclosed or shielded pod and that'll sound different again....

[CNBLU]

well its even better now with the vxr turbo.... words cannot describe it

(if anyone has seen the latest ignition dvd from fast 4's, it sound exactly like the white rx-7):D

[CAL.16V]

http://www.gofastbits.com/index.php?parentid=faqs&option=faqs&sub_option=faqs_bovs

[CNBLU]

excellent site:clap:

[gman]

LoL this thread is funny.

I 2nd that...This is made me laugh out loud...

But have to agree, let him fu*k his turbo if he wants...His car, free country and all that...

I was ROFL & amazed that proof was asked for that compressor surge kills turbos...

Simple answer, imagine a turbine spinning at 110,000rpm, then running into a high pressure wave going the other way...

110,00rpm to zero in 0.25sec = +1500G's in strees applied to have blow seals, bend shafts & turbine blades

But hey, whatever blows your hair back i suppose..... ;)

[Dave]

But its fully sick yoh !

[Wraith]

I 2nd that...This is made me laugh out loud...

But have to agree, let him fu*k his turbo if he wants...His car, free country and all that...

I was ROFL & amazed that proof was asked for that compressor surge kills turbos...

Simple answer, imagine a turbine spinning at 110,000rpm, then running into a high pressure wave going the other way...

110,00rpm to zero in 0.25sec = +1500G's in strees applied to have blow seals, bend shafts & turbine blades

But hey, whatever blows your hair back i suppose..... ;)

Good words there Gman, but I think it'll just fall on death ears with these 'dose' addicts ;)

I'd like to actually see one of em stick to their words of "oh it's ok if it blows the turbo after one day, I'll just get another and do it all over again" - yeh right :rolleyes: LOL :D

[Wraith]

well its even better now with the vxr turbo.... words cannot describe it

(if anyone has seen the latest ignition dvd from fast 4's, it sound exactly like the white rx-7):D

So Gav. the power figure you've quoted elsewhere for your car since fitting the Haltech is with the VXR turbo installed ??

Yours would then be on par with BR's......

[CNBLU]

mine was done on a dynamic systems dyno, if that makes a difference. my tuner said that he has tuned cars on his dyno that say 300kw atw then they go elsewhere and it dyno's 330kw atw. i dunno. all i care is that the car is a rocket all i need now is a EBC to help smooth out the boost.;)

[Wraith]

mine was done on a dynamic systems dyno, if that makes a difference. my tuner said that he has tuned cars on his dyno that say 300kw atw then they go elsewhere and it dyno's 330kw atw. i dunno. all i care is that the car is a rocket all i need now is a EBC to help smooth out the boost.;)

Sounds good.... :)

I was always waiting for someone here in Melb. to do the VXR turbo upgrade on a TS like BR's to see the results 1st hand :)

We'll have to catch up sometime :)

[GreyRex]

I wish I understood half the acronoyms you guys use when referring to all these mods:rolleyes: . What about BATBYGOBSTOPL?? lol

[SSS_Hoon]

I know of 2 GTR's that are used for racing and yes they are stock GTR BB turbos that DOSE as you call it and never have a problem with them and one was even running a S/C with the twin turbo setup sounded funny, and they have no problems with compresor surge on there turbos.


And then also know of ones that have lasted all of 3 seconds (well not exactly but you get the point).


DOSE at your own risk they should make some warning labels for 'DOSE'N' and hand them out with every turbo sold.


SSS_Hoon

[gman]

100% agree....As they say though "Race cars are not road cars"....

From personal experience and IMHO, changing the setting of the BOV can/has made a noticable difference to a track car...

My old STi with a GReddy adjustable race valve, 1.75bar boost, too stiff spring setting and the BOV wasn't working properly, car was a dog out of the corner and getting back on the throttle..

Softened the spring and it made a consistent slightly less than 1 sec difference at wakefield and just over 1 sec at Eastern Creek. Car pulled much better out of the corners as the compressor wasn't stalling on gear changes.

Granted though, drag cars "usually" don't use BOV's for a myriad of reasons...

[CNBLU]

I think everyone needs to give up on explaining these things, and go back to the basics of how a turbo system works.

Ok, air comes in through the filter, then through the AFM (which measures the amount of air coming in so the ECU can calculate the amount of fuel required).
The air is then sucked into the turbo, where the compressor wheel increases its pressure and sends it to the engine. On the way there's an intercooler to lower the air temp, because a by product of the turbo is quite a lot of heat.
Before the air gets into the engine it passes through the throttle body, which is what your accelerator pedal is connected to.
The throttle valve restricts airflow into the engine so that you can vary the power it makes.
When it's open the engine tries to produce maximum power, and when it's closed (almost closed) the engine will be at idle.

So the path of air is: filter -> AFM -> compresor (turbo) -> intercooler -> throttle -> engine.

The exhaust gas flow from the engine is roughly proportional to the amount of power it's making, and that flow is what spins the turbo's turbine, which in turn drives the compressor.
So, the more air going in, the more power, and hence more exhaust coming out, which means more boost, which means more air, hence even more power. It's a feedback loop which is kept under control by the throttle input from the driver.

To keep the maximum boost at a safe level there's the wastegate, which is just a valve allowing exhaust to bypass the turbo, and therefore not spin the turbine any faster, or create more boost.
It works in a very simple way. The valve is held closed (all gas goes through the turbine) by a spring, until it is forced open by a diaphragm driven by boost pressure.
When the appropriate boost is reached the wastegate starts to open, and the turbo will stay at the set boost level while the exhaust flow can still increase as the engine revs rise.

All of this works quite simply under constant acceleration:
Air comes in, is compressed to the set boost level, intercooled, used by the engine, and the exhaust keeps the turbo spinning.

It becomes more complex when you start changing throttle settings.
If the throttle is wide open, and you're at full boost accelerating, then close the throttle (for a gear change, or back off) suddenly the turbo is pushing against a closed throttle, and at the same time the engine has stopped producing exhaust gas, so the turbo starts to slow down.

Now that there's a whole intake system full of compressed air with nowhere to go, and the compressor is not being driven by the turbine - so it can't hold the same air pressure that it did while spinning flat out. The air will start to flow the other way, which means going backwards through the still spinning compressor.
This is where compressor surge comes into play. The compressor is still trying to pump air, but at the speed it's going it can't provide as much pressure as there already is in the pipe.

This causes the compressor to "stall". Stall is a misleading turn used here, because it doesn't mean stall as in to stop spinning. It's the aerodynamic stall, like a plane that's tried to climb too steeply, or has slowed down too much to maintain lift.

The smooth air flow through the compressor blades is broken up, and some of the air will flow back out through the compressor, making a hissing noise.
Centrifugal compressors work on a "squared" relationship for speed vs flow / pressure, so if the turbo slows down to half speed it will only be able to hold a quarter of the boost pressure.

The "chopping" or "fluttering" sound is caused by the accoustic effects in the intake system, determined by the size and length of the piping / cooler.
Rather than air constantly flowing back out of the turbo it tends to come out in bursts, triggered by pressure waves in the piping hitting the compressor.

Generally though the flutter is the sound of the pressure wave cause by the throttle closing bouncing back and forth between the turbo and the throttle plate (the longer the pipes the slower the flutter).
Every time the wave hits the turbo it causes the compressor to cavitate, which makes the noise.

It's not the blades chopping the air making the flutter. Since the blades are spinning at 80000+rpm you wouldn't be able to hear the individual "chops"

If you listen closely you'll actually hear a more constant hiss sound at higher boost levels and rpm when backing off. (ie, a "whooosh" rather than a "chop chop chop")

The loudest flutter tends to occur at lower rpm and boost levels of only slightly above atmospheric pressure (0psi). This is partly because the sound is "chopped" up more noticeably, and partly because the rest of the car is making less noise at lower speeds. This is also where it's least damaging.

Car manufacturers don't like weird noises from the intake system, so they use restrictive airboxes designed to muffle the sound, and more recently (SR20 onwards) used a Blow Off Valve.
The blow off valve provides a new path for air to get out past the compressor. Instead of forcing its way back through the spinning blades it is piped out of the intercooler piping and back into the intake piping before the turbo.

Obviously it could be vented straight out to the atmosphere, but the AFM has already measured that air coming in, and if it doesn't reach the engine the ECU will be injecting too much fuel in its absence.
(Also, venting to atmosphere makes a bit much noise for conservative owners and manufacturers)

The BOV works a bit like the wastegate, in that it's held closed by a spring, and controlled by a pressure operated diaphragm.
This time though the boost pressure helps keep it shut rather than open it.
The control air pressure for the BOV comes from the plenum, which is the chamber between the throttle and the engine.
When the throttle closes the engine creates a vacuum (negative pressure) in the manifold / plenum as it tries to suck air past the closed throttle.
The vacuum is used to "pull" open the BOV, to vent the excess air in the intake system, preventing "flutter" and other noises.

A BOV is a compromise device because, to eliminate all fluttering it will have to open at very low boost levels, and very quickly - which means that it must have a very weak spring. This can cause some leaking of boost due to the valve not staying sealed properly, and also means that every time you back off the throttle, all the pressure in the intake system is vented. When you open the throttle again the turbo will have to build up all that pressure again, whereas if there was no BOV there'd be more pressure remaining as it's a lot harder to get out through the compressor.

Most aftermarket BOVs won't open until you reach 6psi or so of boost (because with an atmo venting BOV if it leaks boost you'll have major problems - whereas a slightly leaking plumb back type won't cause bad running, just a very slight loss of power)

When you start running well over stock boost, and have larger intercoolers / intake piping obviously there's a lot more air in the intake system, and it will be at higher pressure - so when you back off the throttle there's a lot of air trying to escape through the compressor. This means it will be slowed down quite quickly and violently, which puts large loads on the turbo bearings, wheels, and shaft. Repeated hammering by high boost backoffs can harm the turbo, and the amount of slowing each time causes a lag when the turbo spools back up after each backoff / gearchange.

The best compromise setup is to have a BOV which will open when you back off at over say 6 psi, and vent back into the intake to prevent the rich running problems of atmo BOVs. If it's too loose you'll lose boost response due to too much presure being lost on gearchanges, and if it's too tight you'll lose response due to the turbo being slowed down too much - and potentially damaged by the rapid deceleration.

Why does it flutter when my gauge isnt reading any boost?
The reason it flutters even when you can't see boost on the guage is that you're looking at the pressure in the plenum (after the throttle), but the turbo can actually be producing a bit of boost in the cooler and intake piping.

[Kerrie]

flutter aint that bad for a turbo. i dunno about the kkr turbos on euro engines, but the t28 on my s15 put up with plenty of flutters and no problems as of yet.

did you know that the 1.8 turbo silvia and 180sxs (ca18det) dont have a blow off valve at all? yet theyre still running ok 15 years on...

like i said, not sure about the kkr (kkk?) turbos, if theyre weaker or whatever, but nissans seems to cope just fine...

so, did we get this video happening or what?

Will

[CNBLU]

http://au.youtube.com/watch?v=5ZjIO2jvuWo

[OPC]

thread locked

[blueraven]

really? :)

[jsantos]

Just wanted to offer Hott_For_You (http://www.opelaus.com/forum/member.php?u=1580) kudos for his informative post.

[CNBLU]

Just wanted to offer Hott_For_You (http://www.opelaus.com/forum/member.php?u=1580) kudos for his informative post.


your welcome jsantos;)

[Wraith]

Good vid Gav.

I see your keeping the revs well under control and not thrashing it :)

[CNBLU]

Thanks Ange, i do look after it and to tell you the truth it dosent need much on the throttle before i hit 100 anyways, so i very rarely rev it out.... very rarely:D

[Wraith]

Thanks Ange, i do look after it and to tell you the truth it dosent need much on the throttle before i hit 100 anyways, so i very rarely rev it out.... very rarely:D

That makes 2 of us, I thought I was the only one to drive a TS turbo that way...I also try to look after my cars and rarely thrash them :)

Even though mine is stock with only a re-map, it dosn't go any better by revving it beyond say 4,500-5000rpm, so I don't even bother going there...

[rusole21]

Soft!!:D

Gonna take it down the drags Hot_for_yOU??

[CNBLU]

Yeh im planning to once i get my eboost2 installed and tuned, which should be done after new years. will let everyone know on how i go;)

hopefully with the gear based psi fuction i wont be running 18psi in 1st:eek: which is where i get alot of wheels spin.

Gav

[rusole21]

Doubt it could run 18psi in 1st as there wouldnt be enough load. Have you seen it boost that much on your gauge? Interesting.

[CNBLU]

Good point... come to think of it no i havnt, but what i meant was the boost i run in 1st gear causes me to wheel spin.

my bad rusole...

[rusole21]

Na thats cool. I was just wondering. Was starting to think the old VXR turbo is amazing! It still is im sure tho.

Yep thats the prob with front drivers. Too much power makes them a dog to get off the line. Even with an lsd. Watched BR at the drags just sittin there spinnin as the car next to him drove away. He caught him but still not a good thing.

[MrOrange]

God the term 'dose' should be banned. I swear it makes you dumber just reading it.

Sell the Astra and buy a VL

[CNBLU]

lol, OK mr orange!?! its just a sound the car makes just like a BOV!! wouldnt get too worked up on it if i were you. i'd suggest you put some contstructive posts before you start throwing shit around at people.

Been here for a while now and i know the guys on here certainly wouldnt appreciate comments like that coming from a nobody:cool:

[MrOrange]

Lol - too true. I admit, was a bit harsh sorry.

Does my head in why anyone would want to purposely induce compressor surge that's all.

[SSS_Hoon]

God the term 'dose' should be banned. I swear it makes you dumber just reading it.

Sell the Astra and buy a VL, that's where you belong.


hey welcome MR Orange hehehehe who aint a nobody either.


Dose'n is sweet i don't mind it here and there, but would try and stop my car from doing it though.

Its good on someone else's car you get my drift?


SSS_Hoon

[Shaun]

This thread is going straight to the pool room....

Hate to burst you bubble but 1987 techonolgy and 2007 technology are completely different. I wouldnt be suprised one bit that not only blow the turbo if you were to do this that you would throw a fault code with in seconds because the Boost Pressure soleoid is going to go " what the **** is happening here and go **** it im off on to limp mode.

Suggestion is unless you know what your doing with the car dont **** round with it. It will be a costly thing to do for the sake of a sound.

[gman]

Doubt it could run 18psi in 1st as there wouldnt be enough time for it and also torque from the inertia.

Late question I know, but what do you mean by the above????

"enough time for it" & "torque for the inertia" ?????? Me so confused?

The only reason you wouldn't get 18psi in 1st is due to the lack of load (and therefore gas flow) to support 18psi with the standard turbo....

It is not a time thing, its a gas flow/load thing.....Add nitrous or some other form of system to increase load and I guarantee you'll see 18psi in 1st gear....

[blueraven]

^^agreed, its due to load.. you can clearly see an increase in boost both in peak and midrange, and a faster spool time when under more load. For example driving up a hill or having a couple passengers, i have always noticed much higher boost in lower gears with passengers/up hills.

[rusole21]

Late question I know, but what do you mean by the above????

"enough time for it" & "torque for the inertia" ?????? Me so confused?

The only reason you wouldn't get 18psi in 1st is due to the lack of load (and therefore gas flow) to support 18psi with the standard turbo....

It is not a time thing, its a gas flow/load thing.....Add nitrous or some other form of system to increase load and I guarantee you'll see 18psi in 1st gear....


^^agreed, its due to load.. you can clearly see an increase in boost both in peak and midrange, and a faster spool time when under more load. For example driving up a hill or having a couple passengers, i have always noticed much higher boost in lower gears with passengers/up hills.
Yes i know. Im an idiot. I couldnt for the life of me think of the propper term to describe what i meant. Load is the one. I meant the torque wouldnt be reached and therefore as you have said the load and gas flow thru the turbo wouldnt alow it to reach 18psi. By the 'time' thing i meant is that 1st spins up so fast that you wouldnt get to 18 psi unless you have what you also describe. Which he doesnt. Sorry to confuse!