What stall speed for PT??

[Steve Chryssos]

Made obsolete by: CFD software design, electronic transmission control, Overdrive, Lock Up clutches and--believe it or not--disc brakes.

Originally designed for high torque, big heavy cars with drum brakes to prevent "creeping" at stoplights and to try and improve part throttle economy without killing WOT performance. Provided high stall at idle to prevent creeping with drum brakes and the AC on; low stall at part throttle; and high stall at WOT.

Reliability of a multi-piece variable pitch stator is acceptable. But a 1 piece stator with no moving or electrical parts is obviously more reliable.

Nonetheless, it could be incorporated. All things considered, the biggest detriment would be consistency. Drag racers STOPPED using them for that reason. Perhaps a servo based VP stator could fix that, but....

Basically, no one cares about VP any more. For a pro-touring application, we use a looser than stock (but not loose) stall speed based on a CFD designed late model turbine/impeller core; a lock up clutch (for when torque multiplication has peaked); overdrive (too allow for a better gearing) and a computer to get the most of everything. First gear on both a 4L80E and TH400 is 2.48. But overdrive lets you run a lower final drive ratio. That concept is enough to render the VP stator obsolete.

I put my rocket scientist hat on and looked into VP stators for about seven minutes. Reliable or not, all of those little stator fin hinge pins seem contrary to the KISS principle.

[tyoneal]

Originally Posted by streetfytr68

Made obsolete by: CFD software design, electronic transmission control, Overdrive, Lock Up clutches and--believe it or not--disc brakes.

Originally designed for high torque, big heavy cars with drum brakes to prevent "creeping" at stoplights and to try and improve part throttle economy without killing WOT performance. Provided high stall at idle to prevent creeping with drum brakes and the AC on; low stall at part throttle; and high stall at WOT.

Reliability of a multi-piece variable pitch stator is acceptable. But a 1 piece stator with no moving or electrical parts is obviously more reliable.

Nonetheless, it could be incorporated. All things considered, the biggest detriment would be consistency. Drag racers STOPPED using them for that reason. Perhaps a servo based VP stator could fix that, but....

Basically, no one cares about VP any more. For a pro-touring application, we use a looser than stock (but not loose) stall speed based on a CFD designed late model turbine/impeller core; a lock up clutch (for when torque multiplication has peaked); overdrive (too allow for a better gearing) and a computer to get the most of everything. First gear on both a 4L80E and TH400 is 2.48. But overdrive lets you run a lower final drive ratio. That concept is enough to render the VP stator obsolete.

I put my rocket scientist hat on and looked into VP stators for about seven minutes. Reliable or not, all of those little stator fin hinge pins seem contrary to the KISS principle.

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Steve:

Thanks for your input on the Switch Pitch Converter.

Are the Torque Converters that you sell primarily for the PT type application?

I was thinking more of a "Street/Strip" application when I posted, as it seems many, "PT" cars spend most of their time on the Street and the Drag Strip or on a Stop Light dash.

Most have no real Drag Racing priority, thus not a Professional cause, just a "For Fun", lets make some smoke and leave that guy in the dust purpose.

For those, a normal 1600-1800 stall converter for cruising, and with a flip of the switch, a 3000-3200 stall for kicking some ass would be really cool.

I will concede, that the computer programing that can be done with Modern Transmissions is Remarkable, but the option of a distinctive stall change at the flip of a switch would be a real blast to have as an option.

Ironically, a mechanical Switch Pitch converter on a toggle switch does sound like it would qualify as, "KISS".

All things have their purpose, I am just thinking in the vane of, "What's old is New Again", and the SP Converter could very well have a pretty large following with the DD, the Weekend Warrior, or the, "PT", crowd that doesn't spend any time on a track with curves on it.

Thoughts?

Thanks again for chiming in.

Regards,

Ty

[Steve Chryssos]

Occasionally stomping the throttle might be all that a VP stator is good for. Yes, Muscledrive converters are specific to pro-touring cars. Or, to generalize: Short sidewall, overdrive equipped hot rods that emphasize part throttle performance over WOT performance. How'z that sound?

By KISS, I was referring to the added complexity of separate hinge pins, stator fins, and actuators (piston) of a VP stator as opposed to a one piece stator. Even in the 60's, transmission transmission repair shops were prone to to toss the VP stator during a rebuild. I was negative 2 years old at the time. I never drove a VP car. Maybe I just cannot relate.

[tyoneal]

Originally Posted by streetfytr68

Occasionally stomping the throttle might be all that a VP stator is good for. Yes, Muscledrive converters are specific to pro-touring cars. Or, to generalize: Short sidewall, overdrive equipped hot rods that emphasize part throttle performance over WOT performance. How'z that sound?

By KISS, I was referring to the added complexity of separate hinge pins, stator fins, and actuators (piston) of a VP stator as opposed to a one piece stator. Even in the 60's, transmission transmission repair shops were prone to to toss the VP stator during a rebuild. I was negative 2 years old at the time. I never drove a VP car. Maybe I just cannot relate.

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FWIW: The 65 Riviera I have has a SP Converter and if really is pretty cool. I don't have mine on a toggle switch, and the stall isn't set as high as what I wrote in my post to you, although one can buy them that way.

They are a hoot at least in this car. Cruise around town no problem. Stop at a light and stand on it when it turns green and it's almost like a different car. That Riv weighs 2 Tons and with the 65 Nailhead and a cam, it will Roast the tires. 1/4 Mile Times aren't red hot with the mostly stock engine and all that weight, but for banging around town it will surprise folks.

Take Care,

Ty