Lancer Register Forum banner
1 - 20 of 24 Posts
G

·
Discussion Starter · #1 ·
What do dump valves actually do ?

When are they really necessary ?

Should I have one on my VII ?

Which one is the most recommended ?

I had a dump valve on my V, however only really got it fitted for the noise (sad I know), therefore didnt really care too much for what it actually did.
 
G

·
Discussion Starter · #2 ·
TT7,
Vent to Atmosphere dump valves don't really do much extra apart from give you a nice whoosh sound (as you already found out in your Evo V). They can sometimes cause idling problems and they can also make it easier to get flames from the exhaust as it allows the car to run richer than it already does as standard.

Andy
 
G

·
Discussion Starter · #3 ·
Andy,

So they arent necessary and it wont benefit me at all to have one fitted (other than for the whoosh noises) ?

Steve
 
G

·
Discussion Starter · #5 ·
VTA BOV will improve gear chenging times since the turbo will spin freely while you let go from the throttle. It makes a difference, especially in the way it feels. Pick up after gear change is immediate, no delay.

I have seen and heard of problems with the HKS SQV which often require an idle stabilizer (!). Nothing like that with my Blitz SSDD.
 
G

·
Discussion Starter · #6 ·
claud, I know you had no probs with your blitz, funny thing is though a guy is selling his in parts section due to idle probs!?
 
G

·
Discussion Starter · #7 ·
TTV11
Your car already has one fitted as standard, its just that you cant hear it making a noise as it does not vent to atmosphere. Regards, SIMON.
 
G

·
Discussion Starter · #9 ·
Steve, I have a HKS SSQV fitted and have had no probs with it and it is fan-dabi-dozi!!! £250 if you see Justin @ TorqueIC and well worth the money just to scare people when you're bored.....:D
 
G

·
Discussion Starter · #11 ·
if you want your car to run properly,you need a recirculating bov.......period.
if you want to make a noise..............buy bigger maystars
 
G

·
Discussion Starter · #12 ·
Custard is right... except if you have removed you airflow meter and have a map sensor instead.
 
G

·
Discussion Starter · #13 ·
JC/Blade/Anyone!!!

Please explain to a thicky why a recirc BOV is a lot better than an atmos one like the HKS SSQV for your car to run properly..... I'm not doing my beloved motor any potential harm in the long term by having the HKS SSQV fitted am I???

Cheers guys
 
G

·
Discussion Starter · #14 ·
I've a VII and I've got a Sard R2D2 coming from Taka hopefully receive it next week. I'm only fitting it for the sound too :).

My original BOV sounded better/louder after fitting a ARC filter/box, but always wanted to fit a after market BOV
 
G

·
Discussion Starter · #15 ·
let's see if i can remember this properly..

The airflow meter measures air entering the engine, and instructs the ECU to fuel accordingly. The air is boosted by the turbo and as it heads for the inlet manifold is vented to atmosphere by the bov, resulting in less air being used in the combustion process - engine runs rich, so less power - benefit is that it keeps the turbo from stalling, but the standard bov does that. Essentially, the ECU can get confused. Map sensors don't suffer from this, and recirculating means you don't lose the air to atmosphere.

I am sure others can explain this better :)
 
G

·
Discussion Starter · #16 ·
I think you'll find the car runs rich when the dump valve dumps (hence flames),
this wont lose power (especially since you will be on higher booster when you floor
it again) and wont cause any probs at all.

I run the HKS SQV because I love the sound, if I bought a new evo tomorrow, a VTA
dump valve would be very high on my list of mods, probably second to a f*ck off loud
exhaust http://www.lancerregister.com/graphics/Wilk.gif border|EQU| 0 align|EQU| middle >

Do they make your car noticeably quicker ? Of course not, if they did, the rally boys would use 'em !

Justin
 
G

·
Discussion Starter · #17 ·
Think I'll steer clear of the dump valve then, cheers for the info chaps.

Main reason being, I dont want flames melting my rear bumper.

I'm already having probs with discolouring due to the Super Drager !!
 
G

·
Discussion Starter · #18 ·
Someone correct me if I'm wrong but I thought that a dump valve would work as follows:

When closing the throttle, the vaccum in the plenum chamber starts to open the dump valve, therefore releasing the pressure build up between the turbo and the closing throttle butterfly.

When the throttle is fully closed and the pressure is removed, the dump valve closes again.

Now with a VTA, all that happens is that the air pressure is vented to atmosphere rather than back into the intake. When the air is vented with a VTA, further air will be passing the MAF sensor to try and replace it therefore you get the overfuelling. With a recirc, the air is vented back into the intake so no further air is drawn past the MAF sensor and so you don't get the overfuelling.

The point about quicker gearchanges seems a little wierd as well. When you close the throttle, and the dump valve opens, you will drastically reduce the exhaust flow and so the turbo will slow down dramatically whether you vent the excess boost pressure to atmosphere or back to the intake.

Andy (waiting to be corrected :D)
 
G

·
Discussion Starter · #20 ·
So what happens to the air that is vented via a recirc then. That has also passed the MAF and doesn't go into the engine when it's expected to. i.e. it will only go into the engine when you next open the throttle.

Andy
 
1 - 20 of 24 Posts
Top