I have a standard "Bailey's" dump valve, does anyone know what dump valves they used in "fast and furious" the ones that make the high pitched whistle type noise, also the same sound produced on the playstation version "Need for speed" underground, cheers, thick ****!!

 

Eh? No Imprezas come with a Bailey valve as standard.

It'd be impossible to tell you what was used in the film, or indeed the video game. The film sound effects will primarily be added afterwards, and will be unlikely to have actually come from the cars concerned. For all you know the sound could be a cat's bowel movement speeded up a hundred times, a Patriot missile being launched, the dumpvalve off a large truck, or even a recording of the Millennium Falcon's alluvium dampers.

If you want a dumpvalve that makes silly noises, there are a wide variety on the market. The best dumpvalve for your car though (assuming you have a turbocharged Impreza) is the standard (silent) Subaru one.

 

As greasemonkey says, all they do is make daft noises, I have the std "quiet" one on my car and it does exactly the same job as an expensive one that makes huge amouts of noise.

I was also told not to change it by a well regarded subaru tuner as it may/will have running problems but each to their own

Edit: If i was going to buy one for the hey look at me factor then it would be the HKS SSBOV for sure as they are the best sounding

 

Very funny, though what i meant by a Standard Baileys Dump Valve was that the Baileys was standard, 'not to the car'!! I know scoobys dont come standard with Baileys but with a crappy recirculating dump valve. Im quite clued up on sound effects in films also, but thanks for the laugh. Ill be off now to catch a cat, tread on its tail and record the sound, only so i can play it through mr standard kenwood speakers, thats not standard to the car if you see what i am saying!

 

The "crappy recirculating dumpvalve" that comes on the car is a very competent design that still does its job when subjected to much higher (than standard) boost pressures.

As for it being "crappy", well, the only dumpvalves that will work properly on Subaru ECU's are recirculating ones, so if you want your car to work right, that's what you use.

 

know all that! just as well i have an EKUTEC ECU then!

 

You mean you have a Subaru ECU which happens to have an ECUTEK map on it

 

Yes that is correct

 

In which case you still have a Subaru ECU, and a recirculating valve is still the best sort to use...

 

i heard that a turbo-smart dump valve is very loud but also very expensive

 

listen smudger9111 mate, a word of advice DO NOT ARGUE WITH THEE GREASEMONKEY !!!!, as he has probably forgot more about subaru's than you and i already know. no $hit this guy really does know what he is talking about, and NO i aint a fully paid-up member of the greasemonkey appreciation society, just someone who knows good advice when it is given to me.

cheers

stevie

 

I have a baileys atmos one on my 1993 wrx import. Is it better to go to a rec. one? If so, why?
Im also changing my ecu to a 1995 one or a z4, whatever that is! (if anyone nos, please say if its the one to go for on my car)!?

Johnny

 

I coulda sworn I clicked on 'General', not 'Muppets'.

Bonkers.

 

Could have sworn i became a member to scoobynet to recieve help and tips for running my impreza!
I know alot of you think you helped in the development of the impreza way back in the 90s but the majority of people ask questions , open ended questions, in the hope of getting friendly advice and not being ripped because they dont know what pressure the turbo should spin at to get optimum boost to achieve max lateral performance to equal forward motion which helps a persom achieve his/her goal of getting to one place in a motorised vehicle while in a sitting position!
Lets show a bit more decorum when people are asking questions that may be, to the league of subaru development people (now retired), stupid or obvious.

 

The dump valves from the F&F are probably HKS SSQV, my mate has one on his EVO 6 and it sounds identical

 

Agree.
Very well put Johnny sti.

 

Hi Waj

You mail box is full.
Unable to send you a pm

 

Now the search function is working, questions like this are probably best answered there!

Suffice to say though that the Subaru ECU's work by measuring the amount of air that enters the induction tract in order to calculate the correct amount of fuel to inject. A recirculating dumpvalve is necessary to keep the measured air in the system, thus maintaining the accuracy of the airflow measurements.

If you use an externally venting dumpvalve, a lot of the measured air is let out of the inlet, putting the air (and thus the fuelling) values out of whack.

Not too "up" on the earlier ECU's. Again, Search would be your friend. Try searching on "Z4" and "W8", as I'm sure there are a few threads categorising all the pre '97 ECU's somewhere...

 

The way i understand this when you put a DTA DV on is that when it dumps, you loose all the gasses going to the turbo, supposedly to give you less lag, what it does though is as stated, puts the fuelling out (Greasemonkey can probably tell you more about that) because the ecu tries to compensate by putting more fuel in (making it richer)then its confused as you have just dumped all the air out so adds air to the fuel going in the opposite direction and leaning out your mixture too much (not good) or something to that effect.

Tony

 

your probably right but i think the sound is awseome and i'm sure the tubo picks up quicker on gear change with a DTA and how else can you scare grannies.

 

Non. When the dumpvalve (whether a recirc or a VTA) opens, the pressurised air between the turbo and the throttle butterfly is allowed to escape. With a VTA valve, it is let out of the system completely and escapes into the engine bay. With a recirculating valve, it's shot down another pipe back into the turbo compressor, where (provided the valve stays open) it goes all the way around again. Hence the term recirculating.

No, that's an oft-stated fallacy. Anyone who contends that "atmospheric venting dumpvalves cause less lag than recirculating ones" is talking from where the sun don't shine. If all other things are equal*, there will be no difference in the level of lag between a recirculating valve and an atmospheric one. In fact, if there is a difference, recirculating valves are probably better in this respect.

(*All things are sometimes not equal of course, but more of that in a minute. )

In reality, the dumpvalve is there to protect the turbo, and all dumpvalves cause turbo lag, not reduce it. If you open a valve and get rid of all the boost pressure, the first thing the turbo has to do when you open the throttle again is... to re-establish the pressure, so if minimising lag is your aim, you actually want to keep all that air in the pressurised side of the tract.

The argument used by a lot of people to support the "dumpvalves reduce lag" suggestion is that dumping the air out allows the turbo to spin freer. Well, yes, it does, but what's the point of that? By their very nature, turbocompressors aren't supposed to "spin freely", they're supposed to compress air, which they can't do if you keep letting the pressure out of the system.

The way to minimise lag is to not have a dumpvalve at all. Yes, the turbo will stall and chatter when you back out of the throttle, but the air will be kept where it's needed. What's more, as soon as you reopen the throttle, the boost will be instantly available to run through the engine, which means there'll quickly be loads of exhaust gas acting on the turbine, and thus spinning the turbo up to speed quicker than would happen if you dumped out all the air.

The downside of omitting the dumpvalve is, as mentioned, more stress on the turbo's compressor blades, shaft and bearings, which some cope better with than others.

Not quite. It's not that the ECU puts more fuel in. The ECU puts the correct amount of fuel in for the air it's measured. The trouble is that, with a VTA dumpvalve, the ECU's air measurements are rendered inaccurate, so while the fuel's correct, the air's wrong, and the result is a mixture that's temporarily too rich, with accompanying fluffing, plug fouling, bore wash etc.

Oh yes, the "all things are sometimes not equal" comment above. Many aftermarket dumpvalves are adjustable, either by means of different springs, or ways of adjusting the preload on the spring. This can allow the user to adjust the valve in such a way as it stays shut when a standard valve would open. If the dumpvalve stays shut, the effect is the same as running without a valve, as mentioned above. Thus, there can, in these circumstances, be a reduction in lag.

So while the claim that "VTA dumpvalves reduce lag" is erroneous, it can be contended that adjustable dumpvalves (whether recirculating or VTA) can reduce it, if adjusted appropriately. The downside though is the increase in stress on the turbo.

The point remains though that if you are going to use an adjustable valve in an attempt at lag reduction, you would be better off using a recirculating one than a VTA, to prevent the misfuelling detailed above.

As for scaring grannies Eddy, standing on street corners looking shifty would probably do it even more effectively than a noisy dumpvalve, especially if you roped in a couple of pals...

 

Jesus GM couldnt you think of owt else to add to that little lot???

 

What about fitting a Dump valve that is part recirc, part dump. Not sure who makes them other than MRT and they know a thing or two about scoobies.

Do HKS or alike do them????

All the best
Pete

 

I don't like giving half an answer Marx. With a bit of luck folk will read that and start to understand a bit more.... fingers crossed!

It's neither fish nor foul. As mentioned, the only dumpvalves that work properly with MAF based ECU's are full recirculating.

Don't confuse what's works best on the car with MRT's desire to make as much money as they can from as many people as possible.

The reason companies like this sell atmospheric dumpvalves with big **** off trumpets on them is not because they somehow perform better, it's because they know the neds like loud dumpvalves, and want to make money from the ned market. MRT may know "a thing or two about scoobies", but they also know a thing or two about exploiting market demand.

IIRC you can get a recirculating conversion kit for the Blitz valves, but it's a full recirc, not a "both".

 

Can after market DV's cause any other major problems?
Anything that could cause damage to the engine?

 

I'll stick with me Subaru one then


Although, if you had a remap like an ECUTEK could that not be mapped for a DVA ???

All the best
Pete

 

The question you've asked has already been answered earlier in this thread dij, do you not have your reading glasses on? I'm not spelling it out all over again.

Look at the comments regarding rich running and bore wash (as a result of using a VTA valve) and possible turbo damage (as a result of using a valve that doesn't open when it otherwise should).

Pete: No, it's not possible to map properly around a VTA dumpvalve because, as mentioned above, venting air screws up the airflow measurements. If you can't measure the error, you can't (accurately) map around it.

The correct way round this "problem" is to use a MAP based ECU like a MoTeC, GEMS, Link etc. Then it doesn't matter whether the dumpvalve recirculates or not, as the fuelling calculations are based on manifold pressure rather than mass airflow measured at the pre-turbo end of the inlet tract.

 

Greasemonkey, thanks for your input m8!
Was thinking about getting a new dumpvalve, but I aint any more, now I have read your comments.

Cheers norry.

 

I know it can cause damage to the turbo but WTF is bore wash?
I take it that is damage to the bores?

 

Hi mate?
You dont happen to have a non atmos dump vale aswell do you that i can add to my list from you?
I have a baileys atmos but what GM says, i think i will change!