I remember reading that a recirc was better due to it not conusing something in the engine that the atmos did confuse by getting rid.

Is a dump to atmos really damaging to an engine? Or is this a myth and does one hold any benefit over the other <img src="/forum/images/graemlins/confused.gif" alt="" />

Thanks <img src="/forum/images/graemlins/smile.gif" alt="" />

Technically, you will overfuel slightly with a dta, because you lose some metered air from the intake system, where a recirc just sends it back round the loop.

But in reality, no you wont see any difference, and it isn't damaging.

With a recirc dont forget you are dumping CHARGED air back into the inlet tract, don't forget its already been through turbo once, so its heated.

All that aside i run a recirc simply because i feel it runs better with it and its alot, noticealby smoother on throttle lift-off.

but the air your dumping back in is already cooled by the intercooler, so it will be going back through the turbo to be heated up again and then cooled again, which wont make much difference considering the air temp coming out of the turbo before the intercooler can be anything from 80 degrees to 140 degrees where as the air going back into the turbo will be 25 - 50 degrees

The metered air lost is irrelevant as you arent really worried about fuelling when the valve is dumping i.e. when you you lift the throttle.

If the valve dumped air during load conditions then it would be a concern.

Driving wise I never noticed a scrap of difference between the DV26, DV30 or the OE Bosch valve.

Dito above.
Except for the fact that you, if you want to use an atmos valve on a MAF system, should use a twin piston valve. Else it might leak during idle, which could cause the car to stall.
Can see any other difference, except sound of course. If you like the bus/truck sound then an atmospheric valve is the 'correct' choice, otherwise I can't see a reason not to use a recirc valve.

So is there any need for me to change from an atmos to a recirc then.

Reason I ask, is now running slightly more power, I want to make sure I have the best of most items in there, if a recirc is only slightly smoother but offer no mechanical benefit, then I am not sure if thats a reason for me to change.

The only reason to change would be if you want a different sound. Or if your current one is to small, unlikely, but then the choice should still not be between atmos vs. recirc but rather the choice of size.

Well I am currently running a DV26, I am not really bothered about the noise, so I guess I will stay with that then.

I think you should remove the dump valve altogether JimO. That will make for some interesting noises. <img src="/forum/images/graemlins/laugh.gif" alt="" />

It does indeed. <img src="/forum/images/graemlins/laugh.gif" alt="" /> <img src="/forum/images/graemlins/crazy.gif" alt="" />