ecu and anti lag system
 

hi all, i have a my99 sti type R, my car is pritty much standard at the min. but i am going build it up as i go, i would like to have a ECU which i can get programmed as many times as i like. what i need to know is what it a good ECU with a option for ALS. but things i want to keep in mind are "how many people can map it" also "does it cost alot ever time i want to map it"

just one more thing, if someone could explain how a anti lag system works. i would be very greatfull

thanks mark :thumb:

as far as i know anti-lag sys basicly has a spark plug just b4 the turbo which ignights gasses in the system which keeps the turbo spinning. I dont think your turbos last long with them (or thats my understanding of it in the rally world - i think)

Please correct me if i wrong (prob am)

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

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 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 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).

[quote=impreza.dk]http://www.rallycars.com/Cars/bangbang.html

thank you, some very good reading

now all i need to know is what ecu to go for :wonder:

it would be nice to find a ECU with switchable ALS not just a setting for it. reason being i would prob never really use it but it would be nice to know its there if i ever wanted it. (a boy has to have his toys)

thanks again
mark

Your options are:

MoTeC
GEMS
Autronic

The autronic is probably the cheapest at £1495+vat including fitting and mapping. They work very well and provide good road manners. The MoTeC is arguably better, as it has more features, but most of them will not be used on a road car, the price however reflects this, and you are looking at closer to £1800+vat or more depending on the options you have enabled in the ECU.

If you want ALS for competition use, then I would go with the MoTeC option, but for anything else the Autronic will give arguable better value for money. If you want to start modifying the mapping, you will need to purchase a cable from MoTeC and GEMS to use with their respective ECU, this will add £150-£200+vat to the cost.

Can I ask why you want ALS, and what you think it will give you? It's not a magic fix for lag, and is not without serious side effects.

Paul

He wants antilag because he wants to beat you in the SSC06 :D

Very true about the Anti-Lag being detrimental to the turbo, if you think about it your turbo is going to be running all the time (when boosting). Temperatures can go up considerably.

I know somebody who had a switchable ALS on a Escort Cossie. He was blowing up turbo's every 5000 miles. But then again, if you can afford to buy an Escort Cossie, build, upgrade and run it at close 500bhp - you can afford the odd replacement turbo.

If you have a reliable supply of old turbos I would suggest anti-lag, but if not use it sparingly or not at all.

what about a apexi power fc very good ecu

i can see the spinning bit
 

Antilag is very hard to get to work properly with the small amount of air that can get through the idle control valve. To work properly you need the throttle jacked open, which makes an'orrible road car (with no brakes). Also antilag causes turbo's to get so hot that they turn opaque. If you want pops and bangs tell your mapper not to cut the injectors when on over-run.
Pops, bangs, flames and a car that is still nice to drive. Sorted :lol1:

well if i had it built in to the ecu, it is allways there if i do want at a later date.maybe for the odd sprint or two. not sure if its really that good to have thats why i am on here learning more about it.:thumb: not being funny paul but i dont think these items would be made if they did not work or help with lag issues.

so then lets get back on track. i do not really want to start mapping my own car because i would not have a clue about it and would brake it. can alot of places map these with no trouble?? or do alot of places stick to one type of ecu

ps- have you found me a input shaft yet for a RA box;)

I have worked with all the systems mentioned, but I specialise in Autronic. Autronic ALS is just as good as Motec or GEMS, etc, regardless of whether you are competing or not. All the systems mentioned are very capable systems.

Now, with regard to ALS there are a few main options. You can use a fixed throttle opening percentage, which makes the car a little annoying in traffic, BUT it does not use the anti-lag strategy until you switch it on. The ECU will use a strategy commonly called "roving idle" (which makes the car sound as if it is hunting) to keep your rpms down with the fixed open throttle. Without this strategy and the anti-lag off at idle, (depending on how aggressive you set the throttle opening) your rpm would shoot up to 5,000 rpm or even hit the limiter. This strategy is mainly used for Group N rally cars for which older regulations did not allow the use of an external throttle kicker. Some places didn't even allow a switch and the anti-lag was turned on by raising the rpms above a set rpm (for exmaple 5,000 rpm), and would not turn off unless rpms stayed below the set rpm for at least 5 seconds. With an Autronic a fixed throttle opening using roving idle actually cools down the turbo. The turbo's rpm is a bit higher at idle than normal, but there is no heat related stress, actually the opposite, due to the fueling and ignition strategies used to keep rpms down. Fixed throttle is the easiest to setup, as usually you can get enough extra air by maxing out the throttle stop stud, and using a mild anti-lag. If the stud is two short you can always get a longer one, or find some other means. The other option is the use of a throttle kicker solenoid mounted either on the actaul throttle at the throttle body or at the accelerator pedal. With this setup the car will drive EXACTLY like it would without any anti-lag when the anti-lag strategy is turned off. When the anti-lag is turned on, the throttle kicker will push the throttle plate open by the preset amount to allow the extra bypass air needed.

As for the anti-lag itself, it is not as simple as black and white. You can have the anti-lag set very agressively with heavy ignition retard and large throttle openings, or you can have a milder anti-lag with less ignition retard and less throttle opening. No matter which you use, other posters are correct that it is hard on the manifold, turbo and even downpipe, but as usual the more aggressive the anit-lag, the harder it is on the components. This comes down to a driver/'use of the car' choice. On some of the rally cars I have tuned, the drivers like it so aggressive the car will "push" off throttle, others don't like that and prefer it somewhat milder.

A previous post mentioned brakes, and this is a concern. You will not have a problem with your brakes with either setup when the anti-lag is off. You will have enough vacuum to keep the brake booster functional. Even mild anti-lag (low positive pressure in front of throttle plate/low vacuum behind throttle plate, on closed throttle) doesn't usually result in brake booster problems, especially if your brake booster hose uses a one way valve. If it doesn't, you should get one. Aggressive anti-lag (positive pressure in front of throttle plate/low positive pressure behind throttle plate, on closed throttle) will affect the performance of the brake booster, and can be dangerous, as a large amount of force on the pedal is required to apply the brakes.

Now a few myths about anti-lag. The anti-lag strategy is NOT used at all during WOT. It is as if you had it turned off. Anti-lag is usually setup via load or throttle position, so basically the strategy only functions when the throttle or load drops below the set level. Above that level it is not in operation. So the amount of time the anti-lag is in use will be heavily determined by the type of course. A short track with a lot of sharp turns which requires a lot of off throttle will have the anti-lag strategy in operation more than a longer track with few sharp turns.

Dennis
1990 Toyota Celica GT-Four
2001 Subaru Impreza WRX STi
http://member.newsguy.com/~gtfour

Anti-lag does work, but like all things car related, there are trade offs. Rally cars use 32mm and 34mm restrictors, and most road cars use moderate turbos, so anti-lag is very effective in these applications. For engines with a lot more hp using bigger turbos, it requires a more aggressive anti-lag. For example and STi with a stock turbo would require less throttle opening and less iginition advance to produce the same level of anti-lag than an STi with something like a T67.

As for which system, obviously I am partial to Autronic. You buy an Autronic and you buy everything, from communication cable to data logging to A/F ratio data logging to anti-lag etc. No hidden charges, no "well you have to pay to add that feature". I may stand corrected, but from what I undertsand, Motec charges an intial price, then, for example, you pay for cable, then you pay for logging, then you pay for lamba logging etc. In the end though, it is best to go with what your tuner knows best. So my advise, find a tuner that specialises in Autronic :norty:

Dennis
1990 Toyota Celica GT-Four
2001 Subaru Impreza WRX STi
http://member.newsguy.com/~gtfour

Mark,to quote what Paul has already asked:-

Can I ask why you want ALS, and what you think it will give you?

There's no doubt it works in the right application.

where could i get a anti lag system?
 

please help where could i get a anti lag system for my subaru wrx saloon.???!!!:cry:

Why didnt you just start a new thread instead of bringing up an old one?
Now can we have some information about your car, mods, expendature etc?

Tony:)

it does say to search before you post lol

simple answer is dont bother with antilag, it does little except make noise and damage your car.

proper antilag is extreamly agressive and i don;t know a single road car that runs proper antilag.

if your after pops and bangs then just get it mapped on a decat