i was watching topgear the other day and seen this, and if i ever turbo my car i want the waistgate to sound like squirls are being pushed into my engine.

its at about 1:55

YouTube.com

when you take your foot off the accelerator, a wastegate doesn't do anything, the BOV does. that sounds almost like compressor surge mixed with w/ bov. If it is a wastegate, might have some sorta tuned flapper. Sounds like transformers. lol

The aspect ratio of that video make the P2 look like a Smart car. Try this one:

YouTube.com

+2 on the compressor surge....but it might have something to do with the "anti-lag" system.

Suspect that's a proprietary BOV design being used by Prodrive. Watch some WRC footage and you'll notice the Subaru works cars sound nearly identical. The sound is a function of valve outlet size and shape combined with charge volume and velocity. I doubt you will find a BOV on the market like that, but you could always contact Prodrive to get a quote if they make them available.

Bang-Bang (antilag) isn't THAT complicated. Essentially, when the throttle is lifted for shifting gears or controlling a slide, the ECU retards the ignition timing and dumps a crazy amount of fuel into all the combustion chambers. This results in raw fuel entering the exhaust manifold, where it ignites on the interior surfaces of the manifold. The resulting explosion creates pressure within the manifold that is transfered across the blades of the turbine, thereby creating boost.

Just as the internal combustion process within the cylinders exerts downward force on the pistons to be translated into rotational force in the crankshaft, exploding fuel in the exhaust manifold will push past the turbine, making up for lag caused by a lack of exhaust volume. I believe MSnS allows for ALS, but be warned, it's EXTREMELY hard on manifolds and turbos. If you want a manifold that will last more than a year with regular ALS use, I'd suggest building with Inconel and have two or three spare turbos ready to install.

http://www.rallycars.com/Cars/bangbang.html

Just 2 or 3 extra turbos? More than that, my friend that runs rallys in his suby with ALS kills a turbo EVERY event. Usually they just need a quick rebuild because it destroys the seals but occasionally it'll destroy the turbine wheel.

this thread suddenly got too smart for me

Originally posted by 420agreenvilleSC
this thread suddenly got too smart for me

Seems to be a running trend... :P

Originally posted by DR1665
Bang-Bang (antilag) isn't THAT complicated. Essentially, when the throttle is lifted for shifting gears or controlling a slide, the ECU retards the ignition timing and dumps a crazy amount of fuel into all the combustion chambers. This results in raw fuel entering the exhaust manifold, where it ignites on the interior surfaces of the manifold. The resulting explosion creates pressure within the manifold that is transfered across the blades of the turbine, thereby creating boost.

Like an after-burner. I've a cheesy Kenny Loggins song stuck in my head now.

Highway toooooooo the danger zoooooooone.

Thats insane. How do people come up with this stuff? I mean, what would give someone the idea to do that to an engine to make it more responsive. Its crazy how the world works.

Originally posted by 420agreenvilleSC
when you take your foot off the accelerator, a wastegate doesn't do anything, the BOV does. that sounds almost like compressor surge mixed with w/ bov. If it is a wastegate, might have some sorta tuned flapper. Sounds like transformers. lol

heh. tuned flapper.

Originally posted by hazardeclipse tuned flapper.

Waistgat?