PCM 2-Step (studder box)

[Drake]

I saw some talk on another forum about the possibility of a PCM programmed 2-step (studder box). Supposedly (not that there's any verification beyond rumor, that I've heard) this is a feature that will be offered on another editing suite before too long.

Anyone ever thought about this, or know if it's even possible?

[87gmc]

fill me in whats a studder box?

[Dirk Diggler]

2 step

as in two rpm limits one for launching and then a real on used while driving

[Brains]

I swear there's already something in the OS on an 04 GTO similar to this.. With the traction control on, if you load up against the converter the car will start dropping cylinders, feeling EXACTLY like a stutter box.. Turn the TC off, and it doesn't do it any more ;)

[Drake]

My understanding is that the 2-step is like a second rev limiter that works by pulling spark at the preset RPM. Check out Harlan's LS1 2-Step:

http://www.harlan-engineering.com/store/store.html

You can't use one with cats, the unburned fuel will destroy them.

[Dirk Diggler]

That is one form of a two step. Rpm limiting can be acheived by

1. cutting spark (harlans unit)
2. cutting fuel

Both work the same way

1. Launch limiter could be triggered by a depressed clutch to arm it
2. Real limiter fo normal non drag launches.

Our stock limiters cut fuel IIRC

[Drake]

Right, our stock limiters work by cutting fuel, and that means a lean condition which doesn't sound good for those of us who plan on running forced induction.

It would be best to have another momentary switch wired in somehow, like Harlan's unit has, also. I'm not sure how this could be accomplished with the stock PCM. Maybe there are some pinouts that aren't used?

[Dirk Diggler]

Right, our stock limiters work by cutting fuel, and that means a lean condition which doesn't sound good for those of us who plan on running forced induction.

It would be best to have another momentary switch wired in somehow, like Harlan's unit has, also. I'm not sure how this could be accomplished with the stock PCM. Maybe there are some pinouts that aren't used?

I found out the computer cuts all the fuel at that point teh car is just lighting a spark to air with no fuel and it wont lite...

[Delco]

Its already in the cals , a rev limit for each gear and nuetral.
tried it early on for drag launchs but found that it stuttered on takeoff before it registered the next gear so was a wast of time.

just another gimmick