7 Foot

That's because there are so many and negatives are all a lot of people have got regarding VTAs.

You only seem to have positives - right or wrong aside, by your ridiculous logic this makes your points irrelevant too.

STI-R/A

Lol! ridiculous logic!! mate im going by MY personal experience with vta's. Im on my second one had an evo before with a bailey dv - again no problems. loads of mates run tubo'd cars and have had no problems with vta's. Perhaps in yours and other cases it wasnt fitted properly or maybe the dump valve was faulty?

7 Foot

Do you think the people with structured technical arguments are just making it all up?

You could drive along with your head out of the window for a couple of days and have no problems. Not a particularly sound argument for doing it though is it?



I haven't mentioned ever having one.

EddScott

Calm down dear, its only a dump valve!!!

Its not uncommon to hear of people having a few problems after fitting a VTA DV. Lumpy idle, stalling and jerky throttle response. Have to say I wonder weather its the DV or that fitting the DV un-earths other slight problems the car is carrying.

My car can be quite jerky but its not all the time. Occasionally the throttle feels like an on/off switch and I can't get put on the power smoothly. I only had my car for about a month before the DV went on so haven't had as much time with the OE valve as compared to the VTA.

I've got to do the oil tomorrow and fit an earth wire kit so if I have time I might but the OE valve on and see what differences there are if any.

Dark Blue Mark

Mine *felt* better with it off and MPG was imporved.

This was 4 years ago, im a grown up 26 now

Agreed poor fitting is a big cause of the idle probs etc...

MB

PhilA

I also had the dodgy idle and stalling problem but I adjusted the Blitz DV and it went away completely. It was still very jerky on/off all the time no matter what adjustments I made so I took it off. Car feels much smoother and faster with the normal DV on.

STI-R/A

"Do you think the people with structured technical arguments are just making it all up?"

-Where did I say that??

"I haven't mentioned ever having one."

-Im happy for you.

harvey

iTrader: (48)

The very fact that you are getting pops and bangs indicates that your performance is not at optimum regardsless of whether you find any difference. If you are happy running below optimum performance that is your perogative.
Everything said by Brit in Japan regards DVs in this thread is absolutely correct and he has every right to point out the disadvantages of VTA DVs to those that ask questions about them.

I think this indicates that you do not understand what others have already taken time to try to explain to you. Please read what has been said. An uprated ECU has nothing to do with the VTA D.V. To try to help you I will explain as simply as possible.
The volume of air passing into the engine is measured by the Mass Air Flow sensor. This is communicated to the ECU which sends the right amount of fuel to the engine. On a recirculating BOV, excess air on lift off is returned via the BOV and back into the inlet tract after the MAF Sensor. So the amount of fuel and air for that fuel are approximately correct. On a VTA that air goes through the BOV to atmospher so, momentarily there is a deficit in air and the engine runs rich.
In simple terms, this cannot be eliminated by mapping on a typical ECU and MAF set up. Also from a mappers point of view the VTA is far from ideal as he is looking for constant conditions without slugs of excess fuel to make his job harder.
I have no conclusive proof that the momentary richness will shorten engine life but IMHO if it can be avoided that is the best course of action.

An advantage of a VTA DV is that it is easier to instal into a modified system as there is no need to route the excess air back into the inlet tract.

The O/E DV is quite adequate for the majority of applications, even on cars with relatively signifigant modifications. The BOV is releasing pressurised boost air which would otherwise try to go back through the turbo but some cars operate quite satisfactorily with no dump valve at all.
Changing the DV does not add any performance and in the case of the VTA, as already explained by BiJ, probably adds a slight hesitation. Where a change of DV can become necessary is when changing from a top mount intercooler with a flange mounted O/E BOV to a FMIC. A flange adaptor will allow the same BOV to be used quite satisfactorily in the majority of cases.
IMHO there are more important things to spend £80-£150 on than a D.V.(if these are typical prices) unless it becomes necessary because the O/E can no longer cope but like I said that could be a surprisingly long way down the modification trail.

Many cars I have driven, have badly set up DVs which detract from the potential performance and often reduce the life of the turbo. The DV needs to be matched to the vehicle for best results. Forge for instance have four spring strengths, red, blue, yellow and green and further, finer adjustments are possible by shimming.

I have no problem if somebody is motivated and happy to line the pockets of TSL or one of their competitors and if they like the noise their DV makes then good luck to them but it is an expensive way of getting a woosh because I cannot think of much else the VTA does that makes me smile.

BTW my WRX which has around 400 bhp has a plastic recirculating DV from a Seat Ibiza which cost me nothing and that makes me happy.

Gear Head

iTrader: (2)

Well said m8y!

STI-R/A

Aye, very good prof. more f**kin tecchie sh*te. My point about the ecu is this: If my ecu had been remapped then it would be able to cope with a rich mixture as opposed to a standard map which would not henceforth my vta has caused no loss in performance. At the end of the day its every man to his own - you argue that a vta will cause problems based on technical information. I am basing my knowledge on real cars real people who run vtas and have never had any issues.
By the way I never once said that dump valves improve performance.i know they dont hence the reason rally cars dont use them, but there is no hard evidence that they are bad or good for engines - its just a bit of fun and if it helps the car great if it dont f**k it its my car - my problem
Cheers.

Dark Blue Mark

You're missing the point Your ECU cannot be mapped around a VTA unless its non MAF based.

If you refuse to accept the knowledge of some of the most respected people / tuners on here, who have contributed to the post, then I think you know you are defeated.

Do the people you know who run them know what they are on about?! Would they know an issue if they had one?

Rally cars are a whole different ball game and cant be compared to a road car. They generally use PECTEL engine managment or other, and use antilag, hence no need for a DV.

There is evidence they are bad, its all listed above - confusing the ECU, mucking up fuelling, idle issues etc...

Dont mean to be rude, but you cant come on and disrespect things as *techie ****e* when its actually real proof.

http://bbs.scoobynet.co.uk/showthrea...18#post3991718

(Sticky being one of the people with real knowledge on here...)

MB

harvey

iTrader: (48)

STI R/A. I think you are missing the point. You do what you want with your car which is what I already told you politely above but Herbbie asked for advice and several of us have taken the time to present the honest facts (facts not theories) to him and the wider audience so that Herbbie, or anybody else that can read and take in what is being said can make a balanced judgement from a more enlightened understanding of the issues.
They may go with a VTA because the woosh factor is important to them, it matters not but hopefully they will understand the pros and cons.
My post is not but this is f**kin sh*te
You clearly do not know enough about how an ECU works or what it is doing or you would not have made that post.
The fact that you have pops or bangs in your exhaust indicate you are operating below optimum performance.

I know you did not say that DVs improve performance but it is a common misconception which can hopefully be cleared up for some people.
BTW rally cars do run DVs just like standard Subarus.

Now the overfueling that takes place with a VTA is momentary. It cannot do any good. It may reduce the life of an engine over the years of its life. The reduction might or might not be signifigant. I do not know but what I do know is that I do not want any bore wash on any engine of mine or the risk of fuel contamination of the oil, especially when exacerbated by cold operation.

EddScott

Harvey - so what is the noise a rally car makes then?

Many people have told me that a rally car doesn't use a DV and the chirping noise is the excess gass passing back through the turbo - this has always sounded to me as though they mean its stalling the turbo. It just sounds wrong to me but those that have said it to me seem more in the know so I didn't question it.

It doesn't suprise me that fitting a VTA DV probably isn't the best idea in the world but I'm sliglhtly concerned over the extent of damage if any it might be doing? What I do tend to do is when not pressing on or round town or when cold is to not change until the boost pressure has died off enough not to open the DV (if you get me?)

STI-R/A

Mark - im not saying it was remapped for the vta, it could have been remapped for the exhaust and induction mods - more air in more gas out, remapped ecu to provide more fuel to the injectors to compensate for the extra air/fuel. Add cold grade plugs + a vta - car runs fine. Whats the problem with that???

Harvey - agreed, your info is not ****e, but neither is mine.

Mark - The guys I know with big power cars running vta's have their cars tuned by pro's - if their was an issue im sure they would spot it.

Why is it that in this months banzai mag, most if not all the feature cars have dump valves?
Are you saying that they dont know their stuff and that they just bought it for the noise??

Dark Blue Mark

Is seemed like you were implying the car was mapped to have a DV, which it cant, unless the MAF is not being used.

I dont think its a major issue, but I think for the benefit of the noise there are too many downsides for me. But each to their own I guess, you can look at the argument and go which way you choose. Ive tried one, and didnt like the drive or the dip in MPG.

Id have one if it just made a slight noise and didn't affect the car, but they are all waaaaay to loud for me.

I generally go along with whatever the likes of BRD etc, advise. And they won't sell you one.

RE other cars, I expect the big power skylines do actually need a larger capacity DV, as they generally have bigger turbos. This would mean that the flow / pressure is increased and also keeping a big laggy turbo spooled is more important. They are still MAF based, so not sure how they get round it. Maybe the DV air isn't metered, and ties in at a different point after the MAF.

MB

STI-R/A

Cool, good points there Mark.

Re other cars - theres a new age sti in banzai running a blitz dump valve so it cant be all bad for scoobs : )

Cheers.

Dark Blue Mark

Nuff said if its in Banzai

(Jap Max Power)

MB

stellaFella

If you are going to replace a VTA then don't bother with the original Bosch unit. Its Sh**te, put a decent after market recirc unit on. I made the mistake of buying a VTA when my original fell apart.

Dark Blue Mark

The standard bosch one is a recirc not a VTA. The quality of aftermarket VTA's isn't in question, they are actually quite well made, esp the likes of the Forge one. Its the effects we are discussing.

MB

Peanuts

iTrader: (15)

losing battle Im afraid, but a valient attempt none the less

re: banzai newage etc.

there are cars out there that will be running 1.3bar on a bigger turbo without fuelling or remap, doesnt make it right though.
effectively you are making a choice based on the aural effects of the dumpvalve, the only reason for purchase is either:
a) the whoosh
b) mis information from somewhere that its a positive performance mod

it seems the latter has been ruled out and no one is disputing that here, a good start.
question is now only whether whoosh is detrimental to car/engine.
two or three (of which I am NOT one) respected "techie shyte" () experts have come on here and presented a very good arguement, back up with logical progressions through their posts.
if you need another perspective, drop BRDevelopments an Email asking to purchase a big BOV and why you cant see one on the website.
Bob is someone (like Harvey) I have huge respect for and both have helped me out with valuable information and parts at very short notice.
dont be too harsh on everyone, theres a similar thing with lexus lights (50/50 split in scoobynet) and flamer kits etc.
try to be nice to the good guys though, theyve done all the things we normals want to do, only years ago and are willing to share the info for free

Andy

theotherphil

I have both the Forge VTA and the Forge Re-Circ. The VTA gives a nice whoosh but causes running problems as discussed. The Forge Re-circ that I now have fitted works great and the whoosh is still audible throught the inlet tract (just not as loud). The car runs significantly better though....much smoother and boost builds quicker after gear changes.

Peanuts

iTrader: (15)

remove the resonator from the snorkel on classics and the std. recirc goes whoosh like a vta without the assoc'd. problems.
a la when fitting an induction kit...

theotherphil

I agree....exactly what I have done

Mat Mc

I have a 02 WRX with full Scoobysport (Janspeed) system from the turbo back. I fitted a Forge VTA dumpvalve last week and after one week removed it this evening.

Pro's:

1) It looked great.

2) In my opinion it sounded good (to start with)

3) My 3 1/2 year old son loved it.

Cons:

1) Used more fuel. Normally get 250 - 275 miles to fuel warning light from full tank. This week managed on 220 miles. (Could be down to booting it to hear the dumpvalve)

2) Made the car feel jerky. Lumpy when accelerating in second and third from low revs.

3) When lifting off the throttle it seemed to hold boost or lunge.

4) Started the car one morning and it spluttered to a stop. (never done this before)

5) Got a bit fed up with the noise when I wasn't bombing about. Felt like I was abusing the car.

I must say after removing it and going for a drive the car feels faster. Could be imagining it or just didn't notice the loss of performance sometimes associated with VTA's


Matt

messiah

I'm getting a 2nd hand DV made by Forge to go on my very lightly modded MY00.

I understand that there are different springs to go in it that varies how much of a sound you get on lift on (depending on how hard you accelerate). It also has a bung for the recirc pipe.

Stupid question time - do you only get the sound when coming off boost? (ie over 3000rpm for example), or do you always get it even when doing low revs around town?

I don't want to damage my car, but the occasional "woosh" is what I'm after - after reading this thread it's obvious I can't have both - but can anyone recommend a decent compromise setting for the Forge?

Dark Blue Mark

Blue spring should be fine. Red is generally too hard.

Will give the full whoosh on full boost. Bit more jerky on part boost, and less noise. must be posotive pressure there to lift it.

MB

STI-R/A

Once again - each to his own. Peanuts - im not trying to win a battle, im just arguing mine and others personal experiences with vta's.

I admit I bought mine for the noise - I see no other reason to have one unless running bigger turbo/more boost etc...

Re; being nice to the good guys - Im not being un-nice, just having a debate with them. Perhaps some of the more experienced guys on here shouldnt be so quick to slag off noobs when they say they want a d/v, lexus lights etc... - we've all been there at one point. : )
Cheers.