variable pitch torque converters
variable pitch torque converters Who remembers those from the late 60s,not sure which GM the factory put them in but they came in front of a THM 400,I want to say is was a Pontiac model.Seems like it was a good concept,can it be brought back and improved.If I remember right,with a flick of a switch the TC vaines would change pitch thus having a higher stall. 
I had a ST400 out of a '68 Wildcat, was gonna put it
behind the 455 for my Skylark (RIP). From what I can
gather you would get the stall speed difference, but
not very efficient and heavy as hell. The ST400 had one
solenoid valve inside that directed the juice differently
and any TH400 can be modified that way if you get the
parts. But I'm pretty sure you'd rather have a 4L80E
and a lockup, high stall converter instead.
behind the 455 for my Skylark (RIP). From what I can
gather you would get the stall speed difference, but
not very efficient and heavy as hell. The ST400 had one
solenoid valve inside that directed the juice differently
and any TH400 can be modified that way if you get the
parts. But I'm pretty sure you'd rather have a 4L80E
and a lockup, high stall converter instead.
Banned
Joined: Jun 2005
Posts: 199
Likes: 0
we build many here with the super turbine 300 11 inch cores and are currently working on one with our converter supplier pro torque.they actually work quite well with a transmission brake as well.the problem is the buick cases were cast with a port for the vp pump and although it was never a chevy option the early cases did have the signal passage.these cases are quickly becoming extinct.in these situations one must install a cup plug orifice in the case or use a modified vp oil pump that pulls and orifices signal oil from the pump cover.the technology is great and we are looking forward to producing smaller diameter converters by manufacturing the parts needed by pro torque on our new in house haas 5 axis cnc machine.if anyone would like additional info on the vp feel free to email me.
The ST400 was "switch pitch" while the ST300 was a true
(continuously) variable pitch. I don't know what the largest
motor the ST300 was put behind. The ST400 backed up a
430 motor that had about 445lb-ft of (rated) torque, a 10:1
CR and unfortunately did not like a diet of unleaded low octane
gas, plain water coolant and creosote for oil (by the look of
things when I pulled it). I think the Dynaflow trans was behind
6s and maybe the earlier Buick small blocks, 330CI or so.
Swapping the ST400 in is something the GS enthusiasts do,
as a minor heresy (in comparison to, say, an overdrive A4).
(continuously) variable pitch. I don't know what the largest
motor the ST300 was put behind. The ST400 backed up a
430 motor that had about 445lb-ft of (rated) torque, a 10:1
CR and unfortunately did not like a diet of unleaded low octane
gas, plain water coolant and creosote for oil (by the look of
things when I pulled it). I think the Dynaflow trans was behind
6s and maybe the earlier Buick small blocks, 330CI or so.
Swapping the ST400 in is something the GS enthusiasts do,
as a minor heresy (in comparison to, say, an overdrive A4).
SWITCH PITCH! I don't suggest it. Hard to find someone that will work on the trans. They aren't very reliable in my experience. Tried this setup to no avail. Not even a diff TC solved the issue.
Trending Topics
TECH Apprentice
Joined: Jul 2005
Posts: 374
Likes: 0
Check this out. http://www.paeenterprises.com/paeframe.html
Go to the bottom of the page and click on online shopping, then choose switch pitch converters. It's a pretty cool (old) concept.
Go to the bottom of the page and click on online shopping, then choose switch pitch converters. It's a pretty cool (old) concept.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
we have been making a 10" switch pitch converter for about 16 years for the Gm race teams that run Pikes Peak with the th400 trans it works well on the low stall till about 8000 ft up then they go to the high stall for the run to the top.
It likes a low power engine as the efficiency is low in high stall about 84%
the switch pitch lowers the STR from 2.46 to 1.45 allowing the converter to flare up faster
the pump flow is unchanged as the pump blade angles do not change
all it is doing is a lower STR and restricted oil flow to the converter body
in the high stall mode they build alot I mean alot of heat and a huge cooler is needed, with over 3400 stall
It likes a low power engine as the efficiency is low in high stall about 84%
the switch pitch lowers the STR from 2.46 to 1.45 allowing the converter to flare up faster
the pump flow is unchanged as the pump blade angles do not change
all it is doing is a lower STR and restricted oil flow to the converter body
in the high stall mode they build alot I mean alot of heat and a huge cooler is needed, with over 3400 stall
TECH Regular
Joined: Feb 2004
Posts: 439
Likes: 1
From: burbank ca
vp's the reason for the vp in the early gm cars was that the stator in that tc made so much torque the car was hard to stop. plus the 400 trans was developed by buick and the dyna flow had a varible stator that was controlled by throttle opening
Originally Posted by gonzo 6.0
Do you think someday our vehicals will have something simuliar to this concept/function and regulated by throttle position,that would be cool.
Maybe the system would allow the engine to rev down when coasting saving on gas. Less heat production?
Nothing wrong with the current auto though.
Originally Posted by 2002_Z28_Six_Speed
Maybe the system would allow the engine to rev down when coasting saving on gas. Less heat production?
My 1965 Buick Skylark Gran Sport(401 cu.in,325 hp @ 4200,445 ft.lbs.@ 2800)had one.Buicks' version of the 2 speed Powerglide.A 'micro' switch on the throttle carburator linkage controlled the 'variable pitch' aspect.Full throttle activated the switch which in turn changed the 'stall'.I put a switch on the dash so I could control the stall.I was able to choose which 'stall condition' worked best for 'launch' depending upon existing traction conditions,and for top speed runs,I could switch to the 'other stall' when I ran out of RPM and it felt sort of like an upshift to get higher MPH.Longevity and durability were good as the original OEM torque convertor was still in it at 205,000 miles,and that with a 445 ft lb motor
