Torque converter slip to adjust cruise RPM

[EFI]

Sorry if this sounds like a stupid question, but I was talking to some guy with a 5th gen Camaro and he mentioned that after his recent tune he was able to run less RPM while cruising in 6th. When I asked him how, he couldn't tell me but someone else chimed in about messing with line pressure and converter slip to achieve a lower RPM.

Now I know that torque converters can "slip" to keep the engine at a higher RPM than otherwise commanded by the gearing (which I'm dealing with right now as I'm trying to tune my recent 3600 stall), but I never heard of a converter slipping down to allow less RPM than normal. And when logging on the highway at a steady cruise, the converter is locked and there is ~0 RPM of slip, but when it's unlocked and accelerating it can be upwards of 700-1000.

So is this just a feature in the newer 6 speed automatics that I'm not aware of? Or is this just complete BS?

[8850]

Bump your regulator offset up to about 50 psi. Stock is 26.69. Assuming I understand your question. With enough throttle the converter will unlock and with a loose converter the rpm will rise much more than stock even at part throttle.

[EFI]

Bump your regulator offset up to about 50 psi. Stock is 26.69. Assuming I understand your question. With enough throttle the converter will unlock and with a loose converter the rpm will rise much more than stock even at part throttle.

No I get that, I was actually talking about the other way...as in having the RPMs dip lower than stock.

For example, say at 60mph with a stock geared, stock tired, stock stalled car you get 2000rpm cruising. With an aftermarket stall and a tune, that same 60mph now commands 1900rpm because the tuned is making the stall flash negative rpm.

[8850]

The most slippage I've seen in a stock tune is 20 rpm. Can't image having 1000 rpm slippage with the stock converter unless something was wrong. Post the before and after tunes. Most likely something changed in the tune.

[flame]

The reason they use pwm tcc lock up is for driver comfort so things are smooth no clunk no jerking etc. Usually anything over 150rpm will set a slip code and normal slipage being around 50max. Chances are the tuner set it to lock up 100% and may have recalibrated the speedo to make it seem like it is reving that much lower or if the gauges are as bad as the 4th gens you can believe what it reads anyway.