What causes a Rally Car to pop and bang.

[Acheron]

Like, really really loud. Is it anti-lag or something? I need to read up on what that system does, i hear its reducing turbo lag or something. Is that the only thing that causes the rally car noise?

If youre unsure, i mean this;
http://www.youtube.com/watch?v=4TshFWSsrn8&t=0...

[busta]

Yes, Anti lag- injecting petrol directly into the hot turbocharger to keep it spinning inbetween gear changes.

[Megaflow]

Basically, yes. As you said, anti-lag is to reduce turbo lag. What they do is program the ECU to switch to massive ignition retardation when the driver lifts off the throttle, so they are actually firing the spark plugs with the exhaust valves open. This produces enough gas flow to keep the turbo spinning, but because the exhaust valves are open, no or very little power.

Edit: The downside of this is massive temperatures in the exhuast manifold and turbo, drastically reducing the life of both parts, hence it is limited to stage use only.

Edited by Megaflow on Monday 28th February 21:04

[busta]

Ignore what I said

[DIW35]

Most pops and bangs occur when the driver gets it wrong and the car leaves the road.

[davepoth]

busta said:

Ignore what I said

It's sort of true - On the Suck Squeeze Bang Blow Cycle, the bang is usually at "Bang", but in an anti lag condition it's actually at "Blow", when the petrol vapour is in the exhaust manifold.