RMcQ

Ran across this <a href="http://www.atpturbo.com/root/releases/release091004.htm">Virtual Exhaust System</a> on ATP's site.

<i>A system that works on demand” at the onset of boost on turbo and supercharged vehicles to free up all the backpressure (just as a large exhaust system would) in the exhaust stream so the engine can make maximum power. The VES system works as an active dump tube that completely bypasses the restrictive exhaust system when boost is present. As soon as the turbo spools, the valve begins to open. By the time the turbo makes full boost, the valve is fully open.

Highlights of the way VES works:

Completely quiet and stock-like sounding during startup, idle, and cruising.
0 delay in valve response to boost, yet very smooth transition into boost mode.
Automatic open/close under boost using existing boost source on turbo engine and does not rely on wing nuts or electrical motors.
Integrate a boost controller to control when the valve opens or completely turn it off.
Addresses virtually all complaints associated with large 3” cat-back exhaust systems.

Highlights of how our VES components are built:

Solid billet steel construction holds up to high (turbo) temps and won't fatigue and fail in continuous heat.
Precision CNC machined to tighter tolerances for a gasket-less seal.
Built using existing, reliable wastegating technology.
Standard valve built to accept most common actuator bolt patterns for wide range of spring pressures.

Universal and applications specific kits will be made available, but as usual, all components will be available  ea-la-carte” for our DIY and fabricator customers.

</i>
<a href="http://www.atpturbo.com/root/releases/images/release091004/ATP_Virtual_Exhaust_System.wmv">Video demonstration here.</a>

<img src="http://www.atpturbo.com/root/releases/images/release091004/cutout_evolution.jpg">

<img src="http://www.atpturbo.com/root/releases/images/release091004/exhaust_installed.jpg">

Pat-SoCal

Ghetto Fabulous!

nyet

but i question whether making it automatically actuated is reallly what you want.

DAP@EPL

Boost actuated exhaust dump. Cool idea, but the price is too high.

Mark P

Here's results from back-to-back dyno runs with my dumps open and closed. When they were closed, exhaust flowed through my APR exhaust (2 mufflers). There were no cats in any runs. So just bypassing the 2 mufflers showed the difference. At the drags, I saw 2mph gain in trap speed.

<img src="http://ctny.audiworld.com/mark/s4/dyno/104_hptq.gif">

<img src="http://ctny.audiworld.com/mark/s4/downpipes/dumps/dsc06148.jpg">

<img src="http://ctny.audiworld.com/mark/s4/downpipes/dumps/dsc06155.jpg">

MingsS4

<center><img src="http://www.jcwhitney.com/wcsstore/splittest/images/imagecache/10013633.gif;pv23fc064cad113bb8"></center><p>I wanted to buy one from JCWhitney way back in '72<ul><li><a href="http://www.jcwhitney.com/autoparts/Product/showCustom-0/Pr-p_Product.CATENTRY_ID:2006307/c-10101/Nty-1/p-2006307/Ntx-mode+matchallpartial/N-10101/tf-Browse/s-10201/Ntk-AllTextSearchGroup?Ntt=exhaust%20cut">$39.99 Exhaust Cutout valve

MingsS4

The fact that you had closed traps, rather than a "clean" exhaust path, may have contributed to the difference you saw.

Mark P

45 wheel horsepower is due to them being open, not the lack of smooth path with them closed.

The 2mph trap speed gains are comparing open dumps to standard testpipes (clean, smooth path)

so, perhaps it did have contributions, negligible ones.

RMcQ

What body is it? Looks somewhat like an Audi, but not exactly.

Mark P

I assume it's an A4 Avant, but possibly a bad version - don't recall. It was a month before I took delivery on my S4.

<img src="http://ctny.audiworld.com/events/010819terryville/dsc01084.jpg">

<img src="http://ctny.audiworld.com/events/010819terryville/dsc01085.jpg">