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Oh my what have they done?

Posted: Thu Nov 08, 2007 7:47 pm
by saf

RE: Oh my what have they done?

Posted: Thu Nov 08, 2007 9:44 pm
by GrahamS4
If I take it we don't believe their claims, what do we think the outcome of this configuration would be? Other than the pssssshhhhhhh.

RE: Oh my what have they done?

Posted: Thu Nov 08, 2007 10:02 pm
by dummi
whats the problem exactly, apart from the use of a blow off instead of diverter?

RE: Oh my what have they done?

Posted: Thu Nov 08, 2007 10:10 pm
by GrahamS4
The claim:

"Made from billet aluminium, this atmospheric diverter valve dumps the charge-air to atmosphere creating the "Whoosh" sound when the throttle is lifted. This increases both quicker throttle response and higher clamping load to maintain boost pressure more reliably."

Interested in the pros and cons theories.

Re: RE: Oh my what have they done?

Posted: Thu Nov 08, 2007 10:35 pm
by saf
GrahamS4 wrote:If I take it we don't believe their claims, what do we think the outcome of this configuration would be? Other than the pssssshhhhhhh.

Other than the Psssssshhhhhh

A Bang more than likely.

Probably ECU wont know whats going on leading to a while host of problems.

RE: Re: RE: Oh my what have they done?

Posted: Fri Nov 09, 2007 12:27 am
by rikrose
The MAF on the B5 S4 and RS4 is before the DVs in the air input system. If the DVs don't recirculate then the ECU thinks there's a whole lot of air available and going in, which is actually being vented to the atmosphere. When this happens, it'll dump in a lot of fuel which come out unburned. This will have two awful effects - any that gets really hot and hits the hot side of your turbos might actually turn to vapour with a little pop - this is called "fast spool up" on rally cars and is one of the quickest ways to break your turbos, since it's pushing it hard and off center. If you're lucky, it'll get through and only pollute and kill all 3 of your cats. Basically, you're going to be burning insanely rich, and sound like a Nova, Clio or 206 trying to be a Skyline. You don't drive a Nova, Clio or 206, and you're not trying to be a Skyline, and so it doesn't go PSSSHT.

The slightly less awful effect is that all that unburned fuel is an excellent lubricant, and will also cool the cylinder down some.

RE: Re: RE: Oh my what have they done?

Posted: Fri Nov 09, 2007 1:22 am
by s4woody
these whooosh type valves are easy to fit so why not have a set fitted to a car going on the dyno on the 17th..do a whoosh valve run then a 710N run and compare the diff in power if any...

RE: Re: RE: Oh my what have they done?

Posted: Fri Nov 09, 2007 11:09 am
by derdle
Why would we want to make an S or RS car sound like a barry boy car? Part of the appeal of these cars is their stealthiness.

Paul

Re: RE: Re: RE: Oh my what have they done?

Posted: Fri Nov 09, 2007 11:13 am
by GrahamS4
derdle wrote:Why would we want to make an S or RS car sound like a barry boy car? Part of the appeal of these cars is their stealthiness.

Paul
I doubt we would. But as with all mods that reduce refinement, exhausts, sports cats, lightweight flywheels etc, if the gain is big enough vs the loss in refinement, some will decide it is the right modification for them.

RE: Re: RE: Re: RE: Oh my what have they done?

Posted: Fri Nov 09, 2007 6:20 pm
by dummi
unfortunately or fortunately there isn't a gain from this mod

RE: Re: RE: Re: RE: Oh my what have they done?

Posted: Sat Nov 10, 2007 12:14 am
by rolskii
..... oh dear ..... PMSL :jump:

Re: RE: Re: RE: Re: RE: Oh my what have they done?

Posted: Sat Nov 10, 2007 9:32 am
by mikeyquattro
rolskii wrote:..... oh dear ..... PMSL :jump:
Shouldn't you psssshhmsl :roll: :roll: :wink:

RE: Re: RE: Re: RE: Re: RE: Oh my what have they done?

Posted: Sat Nov 10, 2007 1:04 pm
by Doug_S2
start the car - let it idle - watch that piston open - then watch all that unfiltered air get sucked into the engine!

Re: RE: Re: RE: Re: RE: Re: RE: Oh my what have they done?

Posted: Fri Nov 23, 2007 10:27 am
by dodgydave
Doug_S2 wrote:start the car - let it idle - watch that piston open - then watch all that unfiltered air get sucked into the engine!
You can get one with filter to avoid that.

http://www.forgemotorsport.com/content. ... t=FMDVF005

RE: Re: RE: Re: RE: Re: RE: Re: RE: Oh my what have they don

Posted: Fri Nov 23, 2007 10:30 am
by MarkB
Interesting comments they put about the valve.
"All Forge Motorsport Dual-Piston Atmospheric Valves have been designed and built with the intent of venting 100% of the residual charge air remaining in your forced induction system to the atmosphere at throttle lift.





While we have incorporated many elements into the design of the Dual-Piston valves to aid in their compatibility with mass air-flow sensor equipped vehicles, we cannot always guarantee that each individual’s application will be compatible with a valve that vents the charge air into the atmosphere.





Forge Motorsport nor any of it’s Authorized Distributors can assume any responsibility for any adverse effects resulting from the installation of this valve onto a vehicle whose engine-management-system, whether factory or aftermarket, is not capable of compensating for the loss of metered air through a vent-to-atmosphere valve such as this. "