Active valve exhaust systems.

What do you all think of this? Benefits? Drawbacks?

Personally, I think it'll make street driving a bit more comfortable, but at the cost of a little more weight and money. I haven't really found any US websites that offer any great detail about it, apexi.com included, but I found the pics on their japanese website.

http://www.apexi.co.jp/products/exhaust/ps_revmuffler/666.jpg

Here's what the Import Tuner magazine ad said:

"Apexi PS Revolution

The next generation of high performance exhaust systems for modified street cars has arrived! A'PEX is proud to introduce the new, PS Revolution exhaust system. Design for hard tuned, street driven vehicles, the PS Revolution active valve system is engaged and disengaged based upon exhaust gas pressure. This revolutionary new muffler design allows high powered street cars to maintain a tolerable, and legal, exhaust note at idle and light throttle acceleration while copletely disengaging during high throttle, high load situations. Never before has a cylinder type exhaust system seamlessly fused the streetability of a stock exhaust system and the performance advantages of a low restriction racing exhaust."

http://www.apexi.co.jp/products/exhaust/ps_revmuffler/555.gif

http://www.apexi.co.jp/products/exhaust/ps_revmuffler/PSrevo999.jpg

I've actually considered buying one, but i haven't heard anything from anyone yet..so i'm waiting on it.

What i'm concerned about, is the valve opening when its supposed to..cuz if doesn't, that just basically screws up the whole purpose of the design.

It seems pretty much the perfect exhaust though. Low, mellow hum @ cruise...Flow of an N1 @ WOT.

I'll look for more info and post back here if i find some.

Looks like it works similar to a blowoff valve.. pretty failsafe. Makes me wonder if they will have different settings for different exhaust gas pressures.

If it adjusts itself mechanically from the exhaust pressure, then I don't see any advantages to it at all besides altering the sound. It would cause alot of uneccesary backpressure.

A blowoff valve is forced open by the pressure from the compressed air charge; exhaust gases more or less flow out.

It looks pretty useless to me, but let's see what Apexi unveils.

If it adjusts itself mechanically from the exhaust pressure, then I don't see any advantages to it at all besides altering the sound. It would cause alot of uneccesary backpressure.

A blowoff valve is forced open by the pressure from the compressed air charge; exhaust gases more or less flow out.

It looks pretty useless to me, but let's see what Apexi unveils.

Is pressure not caused by compressed air?

Yeah.