Bought a new Forge dump valve and fitted it today, it seems to whoosh at quite low revs about 2k low volume then loud as normal, but driving home and as soon as you change from 1st to 2nd im getting a loud pop from the exhaust and then when dipping the clutch to coast to a stop the car almost stalls

Sounds like an air leak to me but couldnt find anything on inspection, this never happened to the last Scoobys ive put them on anyone got any Ideas please could the DV be faulty ??

 

Overfuelling badly.

 

As a result of ??

Air leak or faulty DV ?? the car ran perfectly before the DV was fitted

Thanks
Rob

 

As a result of fitting a VTA forge dump valve

Your ECU thinks there is more air than there actually is because it is venting to atmosphere and not being recirculated.

 

Would this cause really bad mpg as well?

when i got mine it had a VTA dump valve and never really got any decent MPG out of the car..

I'm looking to get rid of it and find a decent re-circ one for mine.

 

They cant be that bad surely had 2 before never had this happen !!!

 

Would resetting ECU help?

 

Nope. A remap MIGHT, but the only sure way is to go back to the kind of dumpvalve the engine management is designed for: recirculating.

 

Spoke to adam at Revolution where I bought it, who says the spring may not be strong enough for the boost the car is making so ive put the Std one back on for the time being, ill send it back for him to check and see what they come back with

 

Just stick to the standard one mate- you know it works. Why all the buggering about for a "whoosh"?

 

Excellent advice

Dump valves will make you a laughing stock and will cause lots of running issues

Ten years worth of threads on here about Similer problems with Dump valves

 

I'm looking for an alternative to the Baileys one I got on my MY98 JDM WRX Wagon when I picked it up last month. I find it quite embarassing (especially at my age) whooshing around like a young 'un!
Anyone know which one I need to get back to "non-whooshing?"

Cheers

 

Revolution.... advice?

Stay with the original.

 

Back to the original, or a recirculating aftermarket one for bling.

ebay, breakers etc.

 

forgive me if im wrong, but wouldn't the ecu adjust fuelling for throttle position? say when you shut off the throttle it reduces fuel intake? or is there more to it than that?

 

Yes mate, a bit.

The engine meters the air entering. It does so using the MAF, or Mass Air Flow sensor.

Once the ecu sees that, it adds fuel accordingly.

But if you DUMP the air before it enters the engine, or some of it, the ecu will STILL add that amount of fuel because it's working off a signal already received.....but now false, if you see what I mean?

The result is pops and bangs, bore wash, dilution of engine oil, accelerated upper cylinder wear, and can lead to burnt exhaust valves too.

First symptom is the pops and bangs and excess fuel consumption.

Yet there arer STILL those who say, "Do it mate, iof you like the whoosh noise, do it!"

They, however, will NOT be stumping up for any repair bills............

 

+1.

VTA DVs are fine for race/rally cars where dumping the air ASAFP is the aim of the game, but on a road car, lets face it, they're pretty chavy.