4whlpl

iTrader: (1)

Well, that would be a tremendous difference then, but unless you are rally crossing there isn't really a good use for that feature. At the drag strip the two step is good to make the initial power, any shift after that should keep you in the higher rpm range, and builiding boost should not be a problem. Right?

Nez136

iTrader: (10)

To put in into perspective, there are 2 basic styles of ALS(Anti-lag System), Mild and aggressive.

at 0% throttle the mild is building 0-1 psi while the aggressive is building 6-7 psi. WRC cars use an Aggressive style so before they even hit the gas they are at 6 psi. ALS is ment for instent boost no matter what RPM you are at.

Nez136

iTrader: (10)

For the most part you are correct, then you move into the larger turbos like the 42r+ which have major lag but that is when nitrous comes in. You could use ALS but you could break parts a lot eaiser boosting 40 psi on a huge turbo like that vs shooting No2 into the engine and letting it spool up itself. I think AMS is boosting 17 psi on their 2 stage but im not sure. Basically on a street car its not a good idea unless you have a FULLY built drivetrain and are ready to go through turbos.....remmember the second you switch ALS on you jump up about 200* F on your manifold and turbo

JohnBradley

iTrader: (30)

First if you need real everyday experience with antilag you need to contact Dave at Davesport ( http://www.davesport.com/cgi-bin/davesport )

Second, since I have experience with a WRX and antilag let me share what I know. I used an AGP 60-1 full T4 on my WRX and Autronic SM2. Non air injection antilag (which is the type that most ECU's support) is simply alternating ignition timing (cylinder to cylinder) to 25-28 ATDC which ignites the fuel in the exhaust manifold instead of the cylinder. This creates a massive explosion resulting in full spool at any rpm desired. The only selectable (mild or agressive or anything in between) is the air style anti lag which I am not totally sure how it works.

EGT's are increased more than 200*F, we are talking on the order of 500 to 600 degrees. Turbocharger lifespan is somewhere in the sub 10,000 mile range or less depending on usage. Turbine material obviously will make a difference in this, but the turbo will die sooner rather than later (see Rally Sweden 2005, Mitsu EVO driven by Gilles Panizi).

Anti lag can be used to aid spool up AND keep the turbo spooled between shifts. It isnt one or the other. Most ECU's (good ones anyway) also feature a turbo cooldown function that ties into the EGT sensor and wont allow the antilag to run when EGT's stay too high for too long.

It is highly suggested to NOT USE A HEADER with antilag as the material stress far exceeds most piping's design paramters. Use cast iron manifolds for longest life.

Nez136

iTrader: (10)

I could always learn more about ALS

4whlpl

iTrader: (1)

Great explanation!!!

EVOlutionary

iTrader: (38)

Thanks for the info. I am aware of the stresses on the turbo and drivetrain. I will only be using it for 30-60 seconds at a time on autocross runs and with a ported stock manifold, built bottom end and probably a Buschur 20G-9.

From your experience, should I have an EGT probe hooked up to be safest?

EVOlutionary

EVOlutionary

iTrader: (38)

http://www.davesport.com/cgi-bin/davesport

I couldn't find any antilag tuning info there. Could you please point me in the right direction?

EVOlutionary

JohnBradley

iTrader: (30)

Notice I said CONTACT. That doesnt mean look at his site my friend, it means TALK to him. He is one of the best in the NW, and one of a few that are authorised Autronic dealers.

To answer your other question, yes an EGT probe is a good investment for any Turbo car and especially one using Anti-Lag. As far as stress on the drivetrain, anti lag doesnt make power, it just makes what power you have more useable. The stresses on the turbo however will eventually add up. 30-60 seconds at a time probably isnt a drop in the bucket realistically compared to and extended WRC drive. Of all the turbos, the IX is the most antilag friendly from the get go being constructed with Ti and Inconel.

JohnBradley

iTrader: (30)

One other thing I was thinking about as far as free tuning advice (cause Dave probably wont offer free advice) is there was a big discussion about this over on NASIOC quite awhile ago. Tym Switzer was talking about it on their 6 cylinder WRX drag car that they were doing. You might find some helpful bits there.

Antilag tuning=Total timing ATDC, TPS percentage for activation and deactivation, base rpm where it engages and disengages.

Mrleone

I have antilag on my "monster" Evo. I use it thorugh the Autronic ECU.
Its not much used but if I shall drag then I can use it.

Mainly push the button on the mid consol, the gas pedal flat, rev up to 8500rpm,
put the stick into 1th gear.. Let go of the clutch and hold on...

EVOlutionary

iTrader: (38)

Thanks John Bradley for the help. I will check out NASIOC and call Davesport.

I think alot of people on here are confusing dragrace-style antilag (usually clutch switch dependent to hold boost between shift) and rally-style antilag (usually TPS dependent to hold boost while off the throttle coming into a corner).

EVOlutionary

Trojan man

iTrader: (10)

Has anyone experienced any significant boost drop between shifts on the 20g-9, or any near stock turbo setup? From my experience, I don't receive nearly enough boost drop to spend the time/$ tuning an anti-lag, much less the high metal fatigue that will result from combustion occurring in the exhaust manifold itself. I'm honestly surprised a stock turbine wheel and manifold would hold up after 10k miles...you're basically creating a pre-ignition condition in a much thinner walled environment than what you find in an engine block - and we've all seen what results in an engine when this occurs.

On a full race, thermal engineered exhaust system, it'd be cool as hell. On a lightly modded street car/autoX, I'd just learn to shift faster. .02

EVOlutionary

iTrader: (38)

Please see my last post above. We are not talking about shifting and holding boost between shifts. FWIW, last I looked I have the highest trap speed stock turbo'd EVO on the forums (not counting shop cars), so don't worry about my shifting.

Some people act like there is NO lag on a stock turbo. This is not true. As soon as you let off the gas you lose all boost and fall into vacuum. After you shift and get back on the gas it takes a certain amount of time to get back up to full boost. I have datalogged this and on my car, from the time I hit full throttle it takes from 0.3-0.5 seconds to get back to full boost depending on RPM. Maybe it has to do with the 280 cams, who knows, but there IS lag. I know how to set up NLTS and dragrace antilag to fix this problem.

What I am looking for is rally style antilag tuning.

EVOlutionary

JohnBradley

iTrader: (30)

You need to keep in mind pre-ignition (detonation) is a 2000psi pressure spike in the cylinder coupled with HIGH heat. Anti lag has high heat and minimal extra pressure rise over normal combustion. This is why it lasts longer than you think.

EVOlutionary, this is just a broad general sweeping statement, but if you want off throttle antilag, figure out what rpm range you will be in (minimum to maximum) during a run to begin with. Lets say for instance its 4000-7500 rpm. Anytime the motor is less than 50% throttle (TPS value, again hypothetical) Antilag will engage. I am not sure how the AEM is versus the Autronic, but the SM2 makes this really easy to map out.

It all starts with you knowing how to tune, logging a run for a baseline, and taking the ball and running with it.