easy anti-lag

[Jörgen Karlsson]

> >An ALS usually use a valve that bypasses the throttle, adds fuel, retards
> >ignition and misses ignition pulses.
>
> Thank you. I know some systems only use some of these features.
> Do a few of these systems use all of these?

I think that most of the system use all of these but it is not needed in all
applications, the different methods has different problems. I would think
that for example only retarding the ignition will heat the exhaust valve a
lot. Missing to many sparks at a time put more strain on the turbine wheel,
but lets the valves run cooler.


> >One suggestion is to use a switch on the clutch pedal that activates the
>
> >system, if the clutch is down the system will be active.


> I want this to "hit" when decelerating too. I figure a switch of
> some sort on the throttle would be the main control. I think 2
> different "programs" would be the hot ticket. One for drag style
> launches, armed via speed sensor, gear shift selector in 1st, or
> clutch down, or a combo of these. And another for cornering that
> is more aggressive and has a 2-5sec timer on it. The cornering
> system would use the throttle switch.
>
> I'd also like to cut ignition pulses when shifting.....


It looks like we want very similar systems but I am mostly after the
dragrace part. For dragracing a revlimiter  activated by the clutch is
probably enough but the retard will of course help. The revlimiter helps get
consistent launches anyway. The revlimiter needs to be soft touch to act
more like a real ALS system that has a scheme like 'miss miss ignite miss
miss ignite' instead of the hard revlimiter that presents a hundred misses
or soo and then blows your turbo out the exhaust, this is why ignition
revlimiters are not recomended on turbo cars anyway. But if your ignition is
not true sequential a fuel rev limiter is not safe either.






> I might try to get the AIS motor to act like a bypass.
>
> Don't know if it will work or not.

I think that a separate bypass is easier to work with, one that is not
working as a stepper motor is probably best.

> activates a MSD ignition retard (20deg),

> Do you think the 20deg retard would be enough in combination with
> the other features?

Yes, I dont think that more can be used without burning valves anyway.


> I think you would want a "hard" limiter for best results, I could
> be wrong. Haven't tried the rev limit part yet. Retarding the
> timing to 35ATDC makes it hard for the engine to go over

A hard revlimiter is probably as far as you can get from a ordinary ALS.

> 2-3000rpm anyway. I think for the cornering setup I would want a
> random miss, instead of an actual limit, to keep the a/f mix in
> the exhaust manifold lit. Still in the research/experiment stages
> of this, so I could be wrong on all of this.

A random miss is what the soft touch rev limiter work with, this is the
closest thing you can get to a ordinary ALS without using custom parts. But
if you are building something you want something that has a set miss
frequency, like 'miss ignite miss ingite' or 'miss ignite ignite' that is
how most bang bang works. I think that the later sequence is what you are
looking for, the more misses you have the more aggressive the banging on the
turbo is. But on the dragstrip I think that a soft touch rev limiter is
best.


> The car is currently a "suck thru" with the turbo drawing air
> through the throttle body. This really throws some variables in!
> But I've got about a zillion turbo's and other spares for this
> system that I don't care if I blow apart, so this makes for a
> good test subject.

Wasn't it a modern Dodge we talked about? Suck thru setups are (almost?)
only used with carbs... I get dissy when I think of all the problems this
will cause when used together with a bang bang, can you move the turbo to
the right side of the TB? How is the air measured? Does it have an
intercooler?


> I will have my EGT installed before this system is operational.
> More fuel will make it hotter?
>
> Please explain.

The more fuel you have the slower it will burn, the more of it will burn in
the exhaust manifold.


A few WRC teams has (Subaru? and a few others) stopped using bang bangs,
because they had turbo failiures to often.


> >BTW we used a MSD rev limiter set at 2500rpm on a friends
> syclone, it raised
> >the boost from 6psi at 3k without to 19psi at 2.5k with the rev limiter off the
> >line. That is to much...

> Wow. My thinking is that too much is just right!

The same goes for me, but only as it makes the car faster...
We used it to get consistent launches, the only thing that was consistent
with 19psi from the line was the 100yard 4wheel burnouts and the 2.5s 60'
times... This car makes a lot of power, probably the worlds fastest GMC
Syclone with stock block and crank. 11.53 at 126mph on a very slippery track
this weekend, hopefully we will be able to run on a very fast track in a
month.

Jörgen

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