I have a MY00 UK Turbo, which is standard apart from a Magnex Decat downpipe and a Scorpion b/box. I have been having problems with a loss of power when accelerating, particularly in 2nd gear. This doesn't happen all the time, just occasionally, which confused me a bit. I spoke to a fellow scooby owner, and was told this could be something called "Turbo stall", which i hadn't heard of before. He told me that it can be cured with a re-circulating dump valve, but i'm not fully convinced, having heard all sorts about the d/v theory. Any suggestions or advice from the Scoobynet community..?

 

If your only mods are the exhaust bits you mention, then you already have a recirc dump valve fitted which is the best one for the car IMHO. The loss of power may be related to the MAF sensor, which was a known weak item on 98-00 cars, and should be diagnosed ASAP. Is the idle slightly erratic too, as this would confirm it ?

Get it looked at by a specialist mate.

 

They have a real benefit.

The ones that go tsssshhhhh warns others that you are in fact a *****

Dave

 

I was asking about TECHNICAL benefits.....

 

well there is a d/v tssssshhhhhh on my turdo, it sounds nice on times, but was fitted by a cowboy and keeps blowing itself off the pipes. gotta get that sorted, but i thought they had a real benifit and stopes turbo lag, or am i being stupid???

 

Silly me

 

All dump valves wiil prevent turbo stall, be they recircs or VTA (tssssshhhhh) mine incidentally has neither

 

The reason your car sometimes doesn't accelerate well in 2nd gear is that the ECU contains a drive by noise compliance logic, if you hold the revs steady in 2nd gear you can then get half boost. Do a search.

A stiffer recirculating dump valve that doesn't make a naff noise can help with lag between gearchanges, but it can also make part throttle and transients juddery depending on the type.

VTA dump valves can upset fuelling which can damage cats if present, and can cause excessive fuelling on part throttle where an air leak can result.

 

well subaru though it was and put it in the type r's

 

What did they do to the Type R exactly?

 

Bzz,
Sorry to Hi-Jack you thread but my Question to john is on sort of Topic

John,
I just bought a MY99 STi Type R, fairly STD all bar Trust exhaust and Trust induction, apparently imported like it.

I though it had a VTA DV as it was always Pssssssssssssssh ing, doing my head in even bought Std P1 recirc DV. Further inspection now reveals it is a recirc fitted and hearing the Pssssssssssssssh through the Air filter :sad:

Is the only way to quieten it down by fitting a STD airbox or a different Induction kit ??

Tony

 

Tony, it's probably had the resonator removed from the wing. I don't know if this is standard on Type R/RA's, but I've done it to my 03 WRX PPP and it's resulted in slightly lower running temps and (possibly placebo (probably )) a little more power through getting more, cooler air. It has made the recirc DV audible, as well as some induction noise (g/f says it sounds like a washing machine filling ).
If they never had one, I'm not sure whether it's possible to retro-fit, but if it's simply been removed then it should be easy enough to acquire one.

 

i have the std dump valve that came with the car. but my air filter does that psssssssssssssh ing thing. doesn't annoy me cause it isn't loud but what is it doing for the engine ie good or bad. thanks

 

VTA helps your car spit loads of flames, alongside a flamer kit of course, which IMHO is deff a benefit.



Cookie

 

davyboy

My P1 goes Tschhhhhhhhhhh!!

And I love it

So I'm a 40 year old *****!!

So lets hear it for all the ****** out there.........!!! (according to you)

Cheers

Mandi

 

Well looks like im aspiring to be one, just ordered my Forge VTA today. Cant wait.

 

Dont think a VTA D/V will give any added bhp at all but it may help on big bhp cars? I think people mostly have one due to the noise it makes tsshhh or in some cases it is a good reason not to have one. You pays your money and its down to personal preference.

 

Sorry to go slightly of topic...

I'm thinking of doing this to my 02 - did you simply remove the resonator box and let it pull air in from the wing, or did you somehow link it back through to the cold air intake on the front of the bonnet?

I ran an induction kit for a while (till it killed my maf), but liked the induction sound - would like to get some back but keep the standard air box.

Obviously if an induction kit is fitted the resonator is then redundant.....

Thanks,

Rob.

 

A little harsh maybe mate.

Some people just simply like them, granted others may use them for attention seeking, but owning a scoob in general is not the most descreet mode of transport.

Not having a pop at ya, its just i do like them and i dont consider myself a pr!ck.

 

I dont think there is anything wrong with having a dump valve,if you like it you will buy one if not no ones tell you to put one on your car so it is up to you at the end of the day.

 

i have a really really loud turbo XS valve and its mental loud.

no, im not a ***** Davy you gay.

however feel free to say things like that again and recieve a thousand karate chops

 

Might want to work on your insults there friend!

I don't have one but I do like them, I only tend to want Mods that serve a purpose for me.

 

People who have extremely loud dump valves; I respect them It's their car so they can do what they want. No need to call them ******/chavs

 

Off topic but why are you up at this stupid time? I just finished work

 

After speaking to several specialist's on this subject, i found out that the standard valve does a great job upto 350-400 bhp, where an uprated valve is called for. The loud type you are on about can do more harm than good after a while, as they confuse the ECU and over fuelling occurs. This can lead to wash out, but only after a period of time. So unless you are planning big bhp, stick with the factory item it is better for your car. Oh and by the way mine is running nearly 340 bhp and still on the factory one

 

 

You upsetting people again Dave, or are you having a pop at my DV By the way I will be having a look at my std one today and seeing how easy it would be to get it back where it rightly belongs.

Gary

 

my std 1 leaked at 1.4 bar so only approx 310 / 320 bhp, which shown up a det spike on the "cockshrink"

stevie

 

Firstly, by DV - I assume you mean Diverter Valve (or as mostly referred to by Brits a Dump Valve).

All modern turbo engines use them. They protect the turbo.

Their purpose is to exit boost pressure either into the airbox or into the atmosphere when the throttle plate shuts quickly. This is to prevent the created back pressure shockwave damaging the turbo.


There are two main types of DV.

Recirculating DV or Atmospheric DV. Both do the same job... to protect your turbo.

They do not add any more performance, unless the new one replaced one that was faulty.

DVs come in different flavours.

Some Recirculating Ones(usually OEM Bosch ones) are made of plastic and use a rubber diaphragm to divert air pressure. These commonly fail on cars and causes the air system to be in a constantly diverted state, which leads to low boost.

Aftermarket DVs are generally built of billet aluminum and usually use a piston and spring method to divert air pressure. These are more reliable because they don't use a fragile rubber diaphragm - but they are more expensive.

Their resistance to opening can be tuned with different springs, so if you're running a lot of boost, you can tweek them so that they hold that boost before opening.

Atmospheric DVs are usually constructed in a similar way to a recirculating DV but instead of venting to the airbox, they merely vent to air. They use a twin piston arrangement normally to allow the car to idle properly.

I'd always chose a good aftermarket piston DV over an OEM diaphragm DV, cos it's one less thing that usually goes wrong in a turbo system. However, you'll need to remember to regularly lubricate the piston, otherwise it will stick.

Comparisons between Atmospheric DVs and Recirculating DVs?

Cars that use MAFs get a little upset with Atmospheric DVs. These dump, pre-metered combustible air when the throttle-plate closes, which means the ECU has mapped a certain amount of fuel for that cycle. But with that air not there, the car is running incredibly rich for that moment, dumping unburned fuel into a very hot CAT and exhaust, which of-course ignites, causing longer term damage to the ceramic cores.

Aftermarket Recirculating DVs are installed the same way as the OEM one, and just divert the pre-metered air. The air isn't lost, so fueling remains correct.

Atmospheric DVs make more noise than Recirculating DVs. Unless the noise snorkel on the intake is messed with, or you're running an open-air cold feed kit.

So yes, you're car does work better with a DV than without. But probably better with a recirculating DV than an atmospheric DV.

 

Subaru WRC's don't have a DV, I wonder why. Any thoughts?
Oh god I'm in PSL mode