Anti-Lag System, Just a quick Question Options

[bsamps4]

First off: I'm not trying to start a conversation on how to get the anti-lag system available in the WRC model to work.

While painting the non-wrc manifold that i bought earlier this year I decided to tear into my WRC manifold to see how it works. I was suprised to find that when I unbolted the 4 large bolts that hold the piping for the anti-lag on that mine were not "blanked out". Everywhere that I've read says that the anti-lag manifold is blanked so to speak and that there is no pass-through for air flow. Just kind of confused. Anyone else with a WRC that took a second look at their manifold? Mine is wide open and the bolt that I pulled has a port to the top where it actually appears that exhaust gas has flowed through the maze of piping that goes to the valve that sits next to the water cooler.

[bsamps4]

Just snapped a few shots to reinforce what I'm asking.

[96stgreendemon]

I honestly didnt even look at mine when i took it off, think its more in the plumbing than anything.... but i dont have enough money to blow through turbos like that lol

[bsamps4]

Just curious..."blanked" is a pretty loose term without any explanation. I guess i could find out by pushing a wire hanger through the piping to find out...

[96stgreendemon]

could just use an air compressor

[Cuts_the_Pilot]

Mine were open also, after I removed the anti lag valve and such I had to block off the lines myself.

[Neon90424]

If im not wrong theres like a bypass valve that blows cool air into the manifold thru those pipes and a special ecu would trigger it...rich condition and spark if im not wrong...theres are write up some where...

Anti-Lag

The Group A was the first production car I know of with anti-lag standard, although again not operational. The system uses an ECU signal to switch two VSV's on the back of the block which provide vacuum (via a canister) to the special bypass valve fitted right beside the entrance to the IC. This heavy duty metal valve has a poppet valve which when opened directs some of the air (which usually all goes through the BOV) down four metal tubes into the exhaust manifold. A special manifold has a hole just after each exhaust port. A small heatshield sits between the manifold and the intercooler.

How do you make it work? You don't.

Anti-lag is *very* hard on turbos due to the shockwaves and high temperatures produced. Unless you have a rally team budget, forget it.

Here is some of what you need to do to activate it. My bypass valve seems to be jammed shut, maybe it has an internal spacer to stop it opening. The fittings connecting the pipes to the manifold are also not drilled though. With those aspects fixed the system will mechanically work. The VSV's are wired to the ECU, however an aftermarket ECU is needed to apply 12V to make them work. I'm guessing that (like most systems) the ECU retards the timing while continuing fuel injection. The mixture burns in the manifold, keeping the turbo spinning. This is very harsh on the system, therefore the pipes are just to supply cool air to keep temperatures down (conjecture!).

[bsamps4]

I'm actually attempting to remove the system entirely. The VSV on the back is going to have to be removed along with all of the vacuum lines. Only thing i'm keeping is the factory tvsv to control the boost. So i guess i gotta figure out all the vacuum crap by myself since I don't have anyone near by to compare motors with.

[Cuts_the_Pilot]

This is a pic of my car when I first got it.

Quick and simplified anti lag explanation.



The antilag valve (red arrow obviously) is a bit like an external wastegate with a big poppet valve and seat separating the top and bottom chambers. In the following when I say the TOP of the valve I simply mean the top chamber, and naturally the BOTTOM refers to the bottom chamber. The chambers are held together with a V-band clamp.

You can see the Anti Lag Valve bolted (via the bottom chamber) to the head (pretty sure its the head, could be to a bracket to something else, its been many many years since I removed it) in the front of the intercooler connected by a small rubber hose to the TOP of the valve.

The green lines represent roughly how the pipes come off the manifold, they are joined by smaller rubber hoses to the BOTTOM of the anti lag valve.

The blue line connects to the TOP of the valve and is the hose that goes to the blow off valve, non WRC/Group A cars simply have this hose straight on the intercooler.

The idea behind it is when you want the anti lag to kick in, you flatten the throttle and initially you get some boost built up simply from ecu tuning (dump in fuel and cut timing right back). When the ecu sees pressure in the system then the ecu triggers the VSV (behind the plenum runners) and the anti lag valve opens and some of the air in the intercooler flows into the manifold runners, this injection of fresh air significantly helps the ignition that's going on inside the runners creating much more aggressive operation.

The anti lag valve is fixed shut on the cars, I'm not sure how this is achieved, I didn't investigate further but I suspect there is some sort of stopper under the cap (instead of a stopper there needs to be a spring, again just like an external gate)

This post has been edited by Cuts_the_Pilot: Jan 4, 2012 - 4:21 PM