I have a nice new metal DV fitted and read on the fitting instructions from Forge that "ensure valve is fitted in the same orientation as the standard valve, this ensures a much quieter operation"

Does it? Does this mean if i fit it the other way round it will be louder? would this affect boost/ performance at all?

Anyone~??

Some of the guys on SCN claim it holds boost better in reverse aswell. Mine is in reverse atm but thats only because the engine cover fouls the vacuum take off when its the normal way around.

It probably is a bit louder in reverse but their isnt much in it.

Doesn't make any difference to performance at all. A valve is a valve at the end of the day.

TBH, I can't stand the sound it makes when it's in reverse, especially the metal forge/compbrake ones. More like a squeak than a psssshhttt.

Oh, and like Ryan said, fitting it the normal way fouls the engine cover. Put it in reverse and it doesn't.

Mines a cheaper eBay item, which fits perfectly under the engine cover.

I tried it once, made it as far as the end of the road, turned round, went home and changed it back, sounds like your standing on a cat everytime you lift off. Terrible .............

A mate of mine fitted a DV007p to my car.

He fitted it in the reverse position because he read in a few places this is meant to be better!?

Have had no problems with it and it fits under the snazy plastic engine cover.

Although as per post above, the noise can be a tad annoying... but you get used to it.

I've tried it fitted both ways and really didn't notice any difference. However I was thinking about how it operates and came to the conclusion that it should function better (under standard boost application anyway) the correct way round as the recirculating boost will help open the valve. Vacuum opens the valve but when orientated correctly the pressure differences must help it open faster as it's pushing in the direction of travel. If you reverse the valve then the boost when you come off the throttle is just pushing against the side of the valve. Try thinking of it a bit like a syringe I suppose, if you push plunger upwards then it moves. If you push on the side of it nothing much happens!

Think you have that the wrong way round mate. The tip is not under boost pressure. The pressurised air is coming from the pipe on the left which joins to the metal charge pipe running down the back left of the engine. In the standard setup, the charge will push on the side of the piston with the bottom of the piston effectively at atmosphere.

In that case, fitting it reversed would be better, as the boost is acting directly on the piston, not on the side of it, meaning the seals won't wear as quickly.

Edited 21 February, 201115 yr by rk696

I tried it once, made it as far as the end of the road, turned round, went home and changed it back, sounds like your standing on a cat everytime you lift off. Terrible .............

+1

Doesn't make any difference to performance at all. A valve is a valve at the end of the day.

The above would only be correct if, the surface area of the DV piston that the inlet port acts on, is equal to the surface area of the piston that the exhaust port covers.

Unless the two were equal, then turning the DV will alter the pressure that the DV opens and closes.

Bill.

It's opened by vacuum from the top connection..

It's opened by vacuum from the top connection..

Correct, it is.

However, the DV piston is also subject to and effected by pressure acting on the underside of the piston.

Any change in the surface area that this pressure acts upon will alter the threshold value that the valve activates, in relation to the pressure or vacuum applied to the top surface area of the piston.

Bill.

I tried it once, made it as far as the end of the road, turned round, went home and changed it back, sounds like your standing on a cat everytime you lift off. Terrible .............

LMFAO !!!!

So have we come to running it the correct way is better then reverse ? Might try it for the sound to see what its like but more then likly run it the correct way its designed too .

Just fit it the way the manufacturer fitted it!