Hey everyone, just got my hands on a lovely Blitze dump valve for my '99 clasic impreza, fited ok but now getting poping like a rally car. what is it and how can it be stoped. Swapped back to original just in case.

 

Cool! Nowt wrong with that.

I'm assuming you are getting popping from the exhaust?

Atmos DVs can cause this.

 

yup your afm is reading excess air if i am not mistaken causing it to increase fueling to create POP

 

That's good to know, changed back to old item until I can sort the fuel out.

 

even if you get it mapped with the VTA on it will still pop and bang

whats wrong with the popping?

 

popping is cause by the dump valve releasing pressure to early. the ecu reads this and adds more fuel, hence running too rich. the oe valve wont do this. Is your DV adjustable?

 

The car will be overfuelling quite badly, have you noticed an increase in consumption? Too much fuel may result in borewash.

 

Surely its down to the fact that the air flow meter has measured how much air has gone into the engine and therfor the ecu calculates how long the injector stays open or in other words how much fuel to put in and whats happening now that you have fitted a dump valve some of that measured air is escaping and leaving behind a more fuel to air mix.

Im having a **** time aswell since fitting mine, although I would be happy if I was getting your results, all I get is hunting and stalling at junctions. I will have to return to the std dump valve and hope ive not ruined the MAF in the process.

 

my ver 2 sti has full decat and panel filter. i am fitting a blitz vta valve at the start of the week. it pops a little as it is so bring on more popping !!! they are adjustable as far as i can see on mine !

 

I refitted my OEM recirculating valve back on yesterday, what a difference it makes,

 

But is the difference for the better or worst. , please give your view.