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Just ragging on you, Matt.

Anyhoo... it would surprise me if VW/Audi had a 2nd gear lockup because I see no real reason for it. Well maybe it wouldn't surprise me. Our family has been thru GTI, TT, and a couple of A6s in th last 5 years. They have some quirky things about them. But then again, they are German. (So am I). Most electronically controlled automatics will prevent engine overspeed by upshifting even when you think you have locked it in one gear.

My favorite auto trans mode is the high-g fun mode (Performance Algorithm Shifting) first used in the 4T80E in the Cadillac STS a few years ago. That PCM senses throttle position of course, but also lateral gs. So if you are flinging the car around and getting to WOT, it selects the appropriate gear to keep the engine somewhere between max torque and redline even when you lift. It's much like what you would do with a manual.

I rode as a passenger in a GM "ride and drive" in such an STS around a course layed out like an auto-x in the parking lot of Las Vegas Motor Speedway. The driver, a winning auto-x guy with a few Skip Barber schools in his CV absolutely threw the car around, but with active handling and the Performance Algorithm Shifting. All you could hear was tire screeching and the Northstar runnin from about 5k to 6500. The end was about a 100 yard straightaway with a 10 mph 90 at the end. We approached the 90 from about 60+ mph in full antilock braking and full active handling thru the turn. The driver barely clipped the apex cone. He had his ticket lifted by the people running the show, but got a standing ovation from the entire crowd waiting/watching. Fun time.

Yeah, I'm related to him.

With most automatics you can keep the converter unlocked at part throttle by lightly touching the brake pedal. A switch (or the brake lamp switch) tells the TC to unlock when it is closed. I do that when I'm running little tests like I've described.

Jon

 

Well, I did invite that, didn't I? Just to clarify though, I meant one would be wrong in disputing that one post of mine. There are plenty of opportunities to correctly dispute other things I say or write (trust me)!

Yep, this will too, but that's not what's happening here. First, it happens at much lower rpms than would require an upshift - like 2000rpm. Second, the LCD indicator on the dash would indicate the upshift, which it doesn't. Third, going ahead and shifting to third afterward does indeed produce a 2-3 shift as expected, so it couldn't have already happened.

PS - Why did I insist on using 5th gear in my examples of a Camaro with automatic tranny? That wasn't very intelligent...

 

Got ya Boss,

But I meant, if first gear would produce the most change in tanny input/output
shaft RPM, I had thought the Torque converter would amplify this difference.

I think I have it correct now REF post# 117

http://web.camaross.com/forums/showp...&postcount=117

Looking for anyone's approval regarding STR...and also curious if I've answered
Jon's trivia question accurately:

http://web.camaross.com/forums/showp...&postcount=115

 

Now do you REALLY understand what you cribbed?

If a standard torque converter is "3 element", and the T-Glide/Flight Pitch Dynaflow (two names for it) is a "5-element" converter, how does it work?

That's a trick question, Tino. Very few folks could understand it without diagrams, and many would still get lost. It's just hydraulic "magic". I suggest you not clutter your memory bank with it.

Years later the variable pitch stator, pioneered in the Dynaflow, I think, was added to some TurboHydraMatic 400s (THM400) and 425s. In one pitch it gave more multiplication (and STR), but in the other position it gave more efficient 'lockup' well before the days of true mechanically locked up converters. Thae stator was in one position or the other, not infinitely variable as in Dynaflow or TG/FPD.

WAY off topic, huh? Time to get back OT...whatever it was.

 

I looked at the diagrams and still have no clue!

As far as STR goes, one thing that always amuses me when I see it are discussions about choosing a converter based on "STR". First of all, AFAIK there is no standard definition of the term and therefore no standard way to measure it. Second, I would bet that when a converter seller or manufacturer provides a STR spec, it is much more likely just made up than not. I mean, if there is no definiton of what it is, and you don't state how you have measured it, it means nothing so why bother measuring it? If you get my drift. Besides, is more better, less? So far, I haven't seen STR = xxx in a sig, but I bet there is someone out there so proud of theirs that they include it.

Rich

 

Damn, OldSStroker,you got any Hydrostick stories too?thats old school
anyway i think theres a guy around still sells switch-pitches for 400s and maybe 727s[?]. My manual lockup switch will do the same for 4th anyway .
I read and researched STR til i was blue in the face and it is a very valid concept that makes sense and explains alot.............buuuut,of the 3 converters that were on the car trying to find the right one, i had to go with the old *** dyno reading on the street.Granted its the one i believe has the best STR anyway . PI has some STR stuff on their site if youre looking for more to read on, Zero.

 

Don't get me started...

How about the 63 Tempest Super Duty 4-speed automatic PowerShift transaxle. It had either a clutch or a torque converter...your choice and you could swap back and forth. Oh yeah, the clutch or TC was about 18 inches behind the rear axle centerline. It also had 3 concentric shafts. Clutch was a concentric hydraulic unit (in '63!). You wouldn't believe the powerflow if I described it, especially when shifting from 2nd to 3rd. Production was kinda limited: 12 or maybe 13 cars before GM pulled the plug. Six were station wagons. AFAIK,there is only one running example left. I'd sure like to find that seventh coupe.

B&M, among others, I believe, has a converter dyno. You could get some interesting info from it.

 

Stealth, I'm interested. What's the link? I'm not familiar with PI?

Thanks.

 

I'm not postitive it's the same EXACT thing you're talking about or not, but a guy came up to me at work today and told me I need to come and check out this car he has at home. He said it was a 62 or 63, I forget which, and he started described the same thing you just talked about. The clutch being behind the rear end.

Maybe I SHOULD check it out?!!

 

Take pics.

The powershift looks like an aluminum Powerglide case (less converter housing) in front of the differential/rear end iron casting and a similar aluminum transmission case behind the rear end with the converter or flywheel/clutch hung on the back. With the short iron front attachment housing and the converter/clutch, the transaxle is 3-1/2 feet long or more. The fuel tanks were shortened to allow the transaxle to fit. There's a curved torque tube from the front of the transaxle to the bell housing at the back of the engine. If that's what you see, get the VIN. 163P99224 is one I know that has been recovered. They are priceless.

If it's just one aluminum trans case in front of an iron rear end, (no second transmission behind) then an open torque converter, it's just a standard 61-63 Tempest 2-speed transaxle. There were 300,000 of them built. No big deal. That's my guess as to what he has.

 

Zero,
www.converter.com

specifically www.converter.com/torqueratio.htm
i remember there used to be more before the site was redesigned, but theres still some; fairly self-serving like the yank link, but still some other info [opinions].
Like i said, i like mine alot performance wise and driveablity, it fits my particular needs and it takes all the abuse i can throw at it.I had it in for a checkup after fragging the trans [converter was perfect after many bottles +slicks] and was talking w the owner about an anti-baloon plate due to NOS. i told him it was 600 give or take on a 180 shot, he says "call me when it has a 350 shot and we'll discuss it."
thats it for what it is or isnt worth.

 

Hmmmm...

I talked to him today and he said it was a 62. But he also said that it definitely has the thing behind the rear end! So, is that what I'm looking for, or no?

 

Not much chance. It's just a 62 Tempest. That doesn't make it uninteresting by any means. Look at the engine, a 3.2 L 4 cyl. most likely, and the whole driveline. Automatics had the converter behind the axle, manuals had the clutch at the engine. The C5/C6 Vette is somewhat similar, but the converter is just in front of the transaxle, but the manual clutch is at the engine, 36 years later!

Let me know.

 

Stealth,

Thanks for the link. There's a particular line I'd like to question:

Wouldn't it be better to say, "the torque converter allows the engine to wind
up to a higher RPM to allow more instantaneous torque for a short period of time"?

From what I see, the torque converter doesn't really multiply anything but
the input shaft ratio (in relation to the output shaft), it just lets the motor
spin up suddenly (into a higher region of available power).

Otherwise, my car would actually have 600 lbs./ft. of torque @ brake stall for
an instant?

I'm also going to assume there's a fine line between power transfer efficiency
and how much the t-con slips (STR). Obviously a converter that slops around
is good for the initial punch, but then falls short when trying to 'couple' the
engine's energy.

 

Yeah, he said it had a 4 banger in it and it was "slanted". Never seen a slant 4 before! And also that it was an automatic and the converter was behind the rear end.

Like you say, still pretty interesting! I could prolly get it for 500 bux, but I don't need ANOTHER project!