N_Collins

Are they worth it?

If so which is best to go for VTA or closed loop??

I'm thinking about the Biley VTA whats the verdicts?

At the moment I'm on a budget.

Thanks

Neil

Danny Fisher

You can get cheap ones, and expensive ones.

Unless you are running something like Link/Motec/Pectel, I would recommend going for a re-circ. valve.

If you use a VTA, your MPG will go out the window, but if you have a complete de-cat, you will get some very nice flames to order.

Dan

NINJA

danny is right vta will muller ur fuel ..despite what others say it has nothing to do with driving style.
the ecu meters ur air going in and every time above atmo vta will upset the calculations and dump more fuel in hence flames crackles and bangs..this is unburnt fuel
stick to recirc if u have cold air kit u will still get the sound

ChristianR

iTrader: (1)

i have a forge re-circ dumpvalve for sale if you are interested, came off my sti iv. drop me an email.

nom

VTA/re-circ: one makes a noises & stops oil from being thrown on the MAF & turbo and lets a sniff of fuel through on gear-changes; the other squirts oil onto the MAF & turbo but is quiet.
Conceivably, unless you are running higher than normal boost and/or have an upsized turbo, there's little point in changing. 'Between-the-gears' is better with a good BOV than the oem, but some don't notice - it's not a huge difference. The oem can start to 'sing' when it's leaking - time to change then
The APS one (and I think only that one) is a hybrid in that with low pressure dumps it re-circs, with higher it VTAs. Seems a good compromise - there should be little oil-squirting with small dumps () and with big dumps () the odd spot of extra fuel won't go amiss.
Or if the mpg's worrying you, buy a micra

NINJA

lost about 4mpg with the hks over a tank that is a lot

P20SPD

iTrader: (1)

nom, just out of interest how does it squirt oil onto the MAF, as i thought all the recirc bits were after the maf in front of the turbo

Just changed from my APS to a forge recirc, and the car runs alot better through gear changes and on lifting off!

The APS one leaked on the vacuum side.

nom

Hmm, leaking not good - I've just changed to an APS one to try to get rid of the juddering I was getting from the HKS It leaks as well... but I think that was me the gasket is a little worse for wear...

MAF/squirting wrong way, etc: this was Pete's (the Croney one) observation & makes sense. At the point the BOV recircs, there shouldn't be much pressure/air flow in the inlet anyway, but the oil doesn't necessarily have to go in any particular direction even if air movement is away from the MAF - oil vapour is rather heavier than air!. And the MAF is a bit touchy

P20SPD

iTrader: (1)

see your point.

Bob Rawle tested my APS one with a vacuum gauge at the vacuum end, leaked like hell. He then took the adjusting bolt off and wrapped with ptfe tape, he also took the vacuum elbow off and wrapped that in ptfe tape. replace and it still leaked, but with less velocity.

On that basis it was not upto the job it was bought for, so a quick phone call to Jamie and he agreed to exchange for Forge recirc, and a refund as well.

Happy now.

DuncanG

Nom, where does this oil come from?

nom

Oil just gets about a bit. Best ask Pete that one - I just have noticed it in the inlet tube myself & don't like it there, so leave it up to those who understand these things to explain

In the mean time, I've been doing some dodgy calcs re: fuel consumption...

Assuming... 440cc injectors, very lazy ECU dumping 1 second of fuel at 100% duty cycle on gearchange & injectors 100% efficient at rated.

440cc*4/60 (cylinders & min>sec) = 29cc/s

So 29cc of fuel dumped per gearchange/release-of-foot-from-loud-pedal. (quite a bit!)

That's 34 gearchanges (when manifold is under pressure, i.e. not pottering) per litre of fuel dumped/lost due to VTA.

So, actually, quite a bit
Although I think my 1 second of fuel dumped is a bit slightly totally way off! Anyone know how much does get squirted, or rather for how long? More to the point, does anyone care?

I think something must be off here as I must say I have never noticed a difference in economy. Maybe I don't drive properly?
I'm quite happy to 'stand down' over this little debate, but would like more than 'I get a reduction of...' arguments, 'cos I don't so it sounds suspicious to me!

Gez

I discovered that my HKS SQV was leaking but with small adjustments of the black screw behind the unit it stopped. I havent noticed a drop in MPG either.

Cheers

Gez

MCGARY

Hi lads, I see alot of you have APS dunp valves . I recently bought one on the for sale site. It is a big lump of a thing and is there a fitting kit for it as i never got one with it and have trouble getting it fitted. It has four threaded slots on it so it must come with some support bracket??? It is a sti v5 98 and came of a v4 is the same valve??? Any HELP appreciated please Gary ..

nom

There's a sort of elbow joint thing that sticks out from the intercooler (where the OEM ones normally is) - the BOV attaches via the 4 threads to that.
If anyone can get you the adaptor, it's going to be Jamie at JW Racing (email jamie@performanceexhausts.net - don't know how to link mailtos!).

MCGARY

Cheers for reply NOM. I tried jamie no kits available but can sell me a valve he said. I think i am stuck with this one now.Cheers Gary

Fury Pilot

Forgive my hignorance, but there are a lot of TLAs being thrown around that I'm not familiar with.

Today I test drove a car with a changed dump valve, that made a hissing sound everytime I reduced throttle. Is this just to excite the driver, or does it serve some function? (Or does it depend on which one is fitted?) It's an otherwise standard 98S.

nom

WTF is a TLA?
'hissing' sound (normally referred to as 'woosh' I believe ) is the dump-valve dumping to air (VTA - vent to atmosphere) rather than recirculating back into the inlet pipe: what the standard one does.
A quality dump valve should be fast enough to allow the turbo to maintain momentum/build boost again very quickly after a gear change/release from boost by the foot. The standard dump valve works OK, but can wear, and doesn't cope that well with higher airflows (high boost or larger turbo). The difference between VTA and re-circ (apart from how they work) is that VTAs technically should be able to dump faster, but I don't think it makes a lot of odds in reality. There are downsides of both sorts (as discussed above), but a quality re-circ should give the smoothest performance.
Most change for the woosh sound. Some change because the oem is leaking or other mods means that the oem one is, effectively, pants & will eventually break the turbo.
Sorry for all the drivel

Fury Pilot

Hmmm, I replied to this earlier, but it doesn't appear to have come out. :-(

Having since driven an Impreza Turbo w/o the hissy dump valve (i.e with the standard one), I've come to the conclusion that the right dump valve CAN help the hesitation when changing gear quickly. Is this true of all upgrade dump valves?

Sorry for the dumb questions.

nom

Yep, that's about right. A good dump valve helps retain boost. Well, not really, but the effect is to enable a quicker return to power after a gearchange.
Returning to the oem DV after an aftermarket is a somewhat unnerving experience if half-way through overtaking & a quick gear-change is attempted

Fury Pilot

Thanks. Looks like I'll be a total cliche when I buy the Scoob and make my first upgrade the DV. However, I guess this would need to be reported to the insurance company. I hope that they don't want to increase the premium...

john banks

Overfuelling on lift off can degrade oil quality.

The only APS fancy DV I have had anything to do with leaked and caused idle problems. The Forge recirc sounds gay but at least does not leak.

Hoppy

John, when I tried that Forge DV I really didn't like the jerkyness on lift-off. Do you know of a quality DV that doesn't have this additional feature?

Thanks,

Richard.

u r a bus

some, (maybe all) scoobs have dump valves as standard. just you cant hear it unless u get an inductiuon cit. its the little round thing near the turbo. ps need a double piston one, other fcok the motor up

rb5 286

iTrader: (2)

If its just the noise ur after, i have just had a piperX air filter (Cone) fitted, complementing my HKS open neck d/p and super drager zorst, it makes exactly the same noise.

i think its gr8 even tho i cant stand d/v's

wife, in her own words, ' I THINK ITS PANTS!!! '

pi$$ed myself laughing, now she refuses to drive it.

nom

You can get jerkiness on lift-off from the DV being a VTA.

carlpcross

go for a vta
had my forge vta fitted about 5 months ago and no works out at a cost of around 1 pence per grin.
as for the mpg, i have lost around 3 mpg, but worth every penny
(my 99)

carl..