I've got my car locked into 3rd from 43-118MPH for the sake of tuning my A/F and timing.

The car has a 2800 stall Vigilante and makes about 550 ft/lbs of torque out of the 396 with 9psi of boost.

If I'm cruising at 50mph/2800rpm and nail it, the RPMs flash to about 5100 and slowly climb to 5700 over the next 4 or so seconds while the car accelerates from 50 to 90 or so.

I'm accustomed to high stall off the line, but this seems a little weird. Is it normal for a higher stall car to rev up to 5K+ like that and just accelerate while the RPMs stall somewhat constant, even at speed?

Thanks,
Dave

 

It's definitely not normal unless the converter were very loose (which a 2,800 stall should not be). But as to why, I really can't say. Is this a new behavior, or did it start after making some kind of change, or what?

Rich Krause

 

Is that converter a 2800 that you ordered from them (gave them your power specs, etc) or a 2800 that was based on a basically stock setup?

 

2800 based on a stock LT1, I guess.

THe 396LT4 with 9psi stalls it to about 5000.

The 396LT4 with no boost stalls it to about 3800.

So I think its a torque issue :-)

 

You now have a very loose converter. You may have actually screwed it up by overpowering it. I'd replace it with something designed for the hp.

Rich Krause

 

So who makes a stronger converter than Vigilante?

They seem to be about the same as ProTorque, and I've been launching my ProTorque behind a ZZ502 with drag slicks for years without ballooning. What makes you think the Vigilante can't take it?

 

Well, from what you are it sounds like the converter is being overpowered (or has been damaged) by the torque from your combo. Or else, it is simply too loose. I'll bet it's heating up like a bastard with what you are describing. As far as lockup converters, I don't know that much about them. But PI-Vigilante has a good reputation, maybe you need to call them and see what they suggest. Maybe yours just needs to be restalled?

In any case, it sounds to me like your problem is your converter. I have seen the behavior you describe when a converter was simply too loose.

Rich Krause

 

Vigi should have no problem building you a converter tailored to your specs and should take the power level with no problems. As Rich said, you are probably simply just overpowering that converter or it is stalling so high the computer is doing backflips.