427 FE Cobra Street: MSD 6AL or AL2 ?

[patrickt]

Old style 6AL, with a hidden adjustable rev limiter in the glove box. And since all the kids are now off at school, we dress Ellie up for Halloween.

[Bearwolf]

The 2 stage is designed for launching in the straight line variety of racing with an automatic trans. What you could try is setting the lower limiter to 3500 or 4000 rpm and the higher limit to 6500 or 7000 rpm and hiding the toggle switch, turn the toggle on when your sons drive so they are stuck with the lower rpm range and when you drive turn it off and have fun.

I've debated running an al2 on a small block car and limiting myself to 6000 rpm on the street and 7500 rpm on track days.

[AC Ventura]

Okay guys, got it. The 6AL used to have a plug in module to control the upper rev limiter, but the newer 6 AL Digital has dials instead. The smaller packaged 6 AL2 has the latter but additionally a low rev limit, for launch control.
So with the AL2 for launch control, you engage this via an external switch, right?
So you set at 3000 for example, to control wheelspin and no matter how hard you press the throttle, it revs only to 3000, right?
So during this time, all your excess, possibly unburnt fuel is going into the exhaust....
Is this a possible fire risk?
How does the unit remove the rev limit control, once you are rolling? Surely you don’t have to flick the switch while you are trying to keep the car straight?

[Gaz64]

Originally Posted by AC Ventura

Okay guys, got it. The 6AL used to have a plug in module to control the upper rev limiter, but the newer 6 AL Digital has dials instead. The smaller packaged 6 AL2 has the latter but additionally a low rev limit, for launch control.
So with the AL2 for launch control, you engage this via an external switch, right?
So you set at 3000 for example, to control wheelspin and no matter how hard you press the throttle, it revs only to 3000, right?
So during this time, all your excess, possibly unburnt fuel is going into the exhaust....
Is this a possible fire risk?
How does the unit remove the rev limit control, once you are rolling? Surely you don’t have to flick the switch while you are trying to keep the car straight?

With a clutch car (manual trans), you fit a switch to the clutch pedal, and a relay circuit, we'll go into that later, that allows the desired rpm limit with the clutch pedal depressed.
So while staged at the lights, the rpm will hold at the desired limit.
It is a soft limiter, not a hard limiter like the high end.
It drops cylinders as necessary, but fires them on the next cycle, so each plug doesn't foul. It gives crackling exhaust etc, but that's part of the fun.
Others will know what is happening when it does occur.

Gary

[AC Ventura]

Thanks Gary.

I kinda thought exactly that, but as somebody new to this (I'm UK based) I could find no reference to it anywhere. Not on the u tube videos, nothing. Anyhow thanks !