OK, let's understand - this - it up to an individual to choose, there are always people who hate VTAs.

Let's ask the serious question....

....who can explain to me the advantage of a VTA - from a technical perspective?

Why does it make your car run better - not worse?

Trout :D

PS I have heard that those underbody neon strip lights can really improve a standing quarter time - any comments anyone whilst we are here?


[Edited by Trout - 6/3/2002 9:53:30 AM]

I have a 94 wrx which i have just fitted a collins atmos dump valve to but the tail pipe of my exhaust is now really sooted up since i fitted the dump valve , will the dump valve cause any engine damage

I wouldnt have thought it would make any difference as you are only replacing the standard re-circulating valve with a vent to air valve

The Subaru ECU is designed to run with a recirc valve and fuels to compensate for the extra air returning through the induction system.

A dump to atmos does not provide this air and so the car WILL run rich.

DTA valves offer no advantage over a good recirc IMHO. All style and no substance.

Trout :D

Perhaps youre caining it more whooooosh pop crackle!!!!! so youre going to find your exhaust is more black.
Theres no proof that a atmo DV uses more fuel.

What sort of proof are you after? As the good man Trout points out the airflow meter has already metered this air and it is now intermittently leaking so it will use more fuel.

I didnt ask for proof,i know there is NO difference to my fuel consumption on my scooby(1yr on rec/8months on atmo)but there always somebody who hates atmos and preferes recs.

well, it will not use MORE fuel, but it will have LESS air to mix this given fuel with.

Planky,

I wasn't 'hating' VTAs - I was merely commenting that they are a complete waste of time and money - to be frank.

And if it is pretty noise you want - my chirruping recirc is probably louder than most VTAs I have heard on Scoob!

And from the technical perpective - yes it will make the car run rich sporadically as you release boost. Damage - nothing serious.

Trout :D

As well as being rich, it will use more fuel absolute as the air that has leaked instead of being recirculated results in more vacuum in the inlet tract = more airflow across MAF = wider injector pulse widths.

John,

are we agreeing ;)

Trout :D

Don't worry about it! I'd rather my car was running slightly rich than slightly lean, especially after all the carry on with engine failures.

It is rich in completely and utterly the wrong place though!

Coked up plugs - damaged cat - blown out sparks - big flame grilled whopper of a turbo if you have no cat.

Yeah, nothing to worry about ;)

Trout :D

I second John's and Trout's statements. Those who believe that the car is NOT running rich are mistaken.

RT im NOT mistaken my cars doesnt use anymore more fuel and most of my mates havent seen any change in fuel consumption.
anyway its up to the individual to choose.

As a neutral party I do concur totally with Doctor Banks - even tho I have a Blitz VTA myself!!

MarkF,But as standard, they run stupidly rich anyway so it's even more stupidly rich with a VTA DV.

There is no chance of it running anywhere near lean if everything is working correctly.....

Matt :)

Quote:
"RT im NOT mistaken my cars doesnt use anymore more fuel and most of my mates havent seen any change in fuel consumption.
anyway its up to the individual to choose. "


I never questioned your right to choose.

I am simply telling you that you (and your mates) are wrong. It is not a question of using more fuel, but having less air to mix the fuel with, as all of it has escaped while making the pssst!

Anyway, it's up to you. Go ask any person worth their salt, and they'll tell you that the only way to run an atmospheric BOV is to use MAP instead of MAF for ECU load.

Its a fact.

Trout, what recirc BOV are you running?

trout....

You have not heard an HKS SSQ dump valve on a scoob then..... i can defo say they are alot louder than a recirculating one..... one of the main reasons for the recirculating DV is so it is quiter....!

Dan

RT,

it was standard - but then I changed intercooler to a Phase 1 IC so I needed to buy an aftermarket one - got a Forge that has been shimmed to leak more slowly - holds the boost a shade longer for gearchanging on track and makes a WRC chirping noise (I know the latter is unnecessary!)

Trout :D

Dhorwich,

have you heard my car?

No - well pass judgement when you do. I was not after big noise specifically - but it is at least as loud as the HKS one.

Trout :D

Trout,
Can I have the exact Forge model you have? If its not too much trouble...
tks.

RT,

it is the MY98 Dump Valve with shim kit. I don't think I ever saw a model number!

Trout ;)

WEBSTER STOP WINDING THESE PEOPLE UP AND TELL THEM YOU ARE A FULLY TRAINED MOTOR MECHANIC. MINE RUNS RICH AS WELL BUT F£$K IT, IT'S FAST. THANKS FOR THE HELP TODAY I KNOW THE COLOUR LOOKS RUBBISH & IWILL DO SOMETHING ABOUT IT IN 6 WEEKS TIME.

This forum is too egalitarian to allow people to pull rank ;) and informed debate holds higher kudos.

ALL I WANT TO NO IS AM I GOING F+++ MY ENGINE UP OR NO , CANT AFFORD BIG REBUILD BILL

A VTA is VERY unlikely to lead you to an engine rebuild.

Trout :D

PS But there again I am not a qualified mechanic - so what do I know?

WEBSTER QUIT F$£KING MOANING IT NEVER COMES OUT THE F$£KING GARAGE ANYWAY!!!!!!