Quantcast

4130biker

PM me about Tantrum Cycles!
May 24, 2007
3,904
442
Lizard Town
Ok, I love the first ones, but I can't help but wonder, what's with all of the "popping" noises coming from this new (Ford) car?
 

3D.

Monkey
Feb 23, 2006
899
0
Chinafornia USA

pretty impressive i think :thumb:
between his previously shown talent for smashing mercury filled cfl bulbs and now his knack for 'hot boxing' dudes on fat guy security guard scooters, a 3M respirator sponsorship should be a top priority in the up coming season.

insane driving throughout though.

the spun off tires at the end was a bit much.. he's f ucked broke when the carbon cap and trade laws set in:rofl:
 

stevew

unique white person
Sep 21, 2001
31,693
2,633
has he won anything yet?

i'm also happy i have never bought a pair of DC shoes.
 
Last edited:

bizutch

Delicate CUSTOM flower
Dec 11, 2001
15,922
8
Over your shoulder whispering
I like the one piece of raw driving not of the whole thing when he dives into the bank in the opening segment and immediately smacks the crap out of the wall.

Wonder how much that segment cost?
 

Jimmysal

Monkey
Mar 26, 2010
238
0
Vermont
Basically, the the extra fuel that is dumped into the combustion chamber results in incomplete combustion in the cylinder. This leads to prolonged flame front as the charge is moved out through the head, into the exhaust manifold and the turbo. This is hard on the turbo and the exhaust valves and guides naturally. This combined with the fact that you need to address cam timing issues to take full advantage of such as system is why you only see it on vehicles like this.

The thought here is that the extra energy stored as a compressed gas mixture in the exhaust system after a downshift will keep the turbo spooled for the next gear. Less lag, more uninterrupted boost and therefore available power to move the car.

The popping is a result of unburned fuel in the exhaust as it exits the car. Basically, you have that fuel suspended in an extremely hot gas mixture without adequate oxygen to form a flame kernel. The fuel is there, atomized, and hot enough to combust, but there is no oxygen to react with. Once it makes its way to the end of the exhaust, atmospheric oxygen completes the equation and you get BRAPBRAPBRAPBRAP.

To answer Jon's question, I've raced autox, rallyx, stage rally, SCCA club road racing, hillclimbs, and I've done 2 Gymkhana events.

Fun fact: My 911 does this as well, but not because of an anti lag system. The way the mechanical fuel injection works on my car creates a slight lag between throttle off and fuel reduction that replicates this. That combined with my :cough: minimalist exhaust results in 3' or so flames out both sides of my car when I shift.
 

IH8Rice

I'm Mr. Negative! I Fail!
Aug 2, 2008
24,554
488
Im over here now
I still dont get it. Why does the anti-lag system make that noise?

Inquiring minds are intrigued by this as I have never heard of it before and would like to know how this works...
this should be easiest to understand the banging noise you are hearing... a ALS system basically keep the turbos spooled up enough to prevent lag that all turbos suffer from, especially high performance models.
When the driver lifts his foot from the gas pedal the ignition timing is altered with sometimes 40° or more of delay (retard) and the intake air and fuel supply mixture is made richer. The inlet butterfly is kept slightly open or an air injector, bypassing the inlet butterfly, is used to maintain air supply to the engine. This results in air/fuel mixture that keeps getting in the combustion chambers when the driver no longer accelerates. The ignition being severely delayed, the air/fuel mixture reaches the exhaust tubes mostly unburned. When the spark plug fires, the exhaust valve is starting to open due to the ignition delay mentioned above. Additionally, the exhaust temperature being extremely high, the unburned fuel explodes at the contact of the exhaust tubes. Luckily the turbo sits right there and the explosion keeps it turning (otherwise it would slow down since its intake, the exhaust gases, is cut-off). The effect is vastly lower response times with some downsides:
specifically... if the same processes are going on, why are toyota/mitsubishi systems quiet while ford/subaru are loud
each car has their own unique sound to them (obviously) and each form of ALS has their own unique sound too