Ok I'm finally getting this automatic transmission thing down but there's two things I can't wrap my head around yet nor can I get the answers. Well one I think I know the answer but not fully. So my questions are...

When someone says some stalls "couple faster" than others, what is that? Is that how fast they downshift and flash (aka get you going) from a roll? If so why not just say "flash faster"? If not, what the hell is it?

I've read that from a roll you want a stall with better shift extensions? Is that how much RPM they drop per shift?

Finally I haven't seen information on either of these on manufacture's sites. So how do you know what stalls are good and not?

 

After ~25 years of racing and modifying automatic transmission vehicles, I've never heard of the term "couple/coupling" before. Perhaps it's a more recent term for something that also has another, older name.

You are correct about shift extension though. This term relates to the rpm drop (or decrease of drop with the improved "shift extension" of a higher stall speed) after an upshift.

 

I think it is used in terms of when the impeller and turbine are spinning close to the same speed= most efficient point of the converter.

 

After a shift it is where the rpms land after the shift. Like my car I run a pretty loose converter and it's a 4400.
I shift at 7100 rpms and after a shift my rpms only drop to around 6200 rpms.

This is not a upshift comparison but this is my car going down the freeway at 80 mph in od with converter locked. I then go wot downshift into 3rd. Watch the rpms. Should give us a little idea on shift extensions especially if you're used to tight/ efficient low stall speed stock converters.

 

Interesting. I didn't realize there was a specific term for that, but it makes sense. Here's a tech article which references that term:

http://www.hardtail.com/techtips/torqueconverters.html

 

Like with my setup it's around 66-6700 rpms.

Good article also

 

Honestly with such a complex part I thought there would be more information ready when you go to buy one. Or am I wrong here and a 3600 from FTI is basically the same as a 3600 from Yank?

Assuming I'm right, how does one figure out the placement of shift extensions before buying a stall? Also how does one figure out the "coupling" of each converter without buying one?

 

I went with the ss4000, and shift at the same rpm as you, my rpms drop from 7100 to 5900. I wish I would have went with a looser converter like yours.

 

I have ran the ss and pt series converters and like them both but absolutley love the n/a pt series converter.

 

They may be similar but probably not the same.

Imo for most a off the shelf converter is fine but you can call and have one speced also.
There are just to many variables to put a simple guideline on a converter website on which to buy.
Different diameter, n/a, boost, nitrous, vehicle weight, shift rpm ect.

All converters are not all the same.
You could have something like I have pt4400 rated for 650 whp n/a and it's amazing.
Then you could have a different diameter 4400 nitrous converter rated for say 1500 whp and if I put that converter in my car I would probably be lucky if I could do a burnout power braking it.

What ya looking to put it in?

 

The term "coupling up" is mainly used in non lockup converters. Its basically the point at which the converter feels closest to locked. Its especially important in turbo aps.

 

A heavy *** G8 but it will have a 6l80 and not the usual 4l80 (I think) most fbody guys are used to here.

I probably would go with something like the PT4000 but I don't want to drive around town like a CVT transmission at 3,000rpms all the time before lockup and have to go half throttle to get the car going. Plus I've heard that heavier cars make the looseness of the converter even more apparent while driving.

But I do want that hard hitting N/A stall and a GOOD roll racing stall.

 

Then I would definitely recommend the pt4000.

I will take a video today of my car driving and post it later today.
It does not take 3000 rpms to get moving and drives very nice.
You will see what I'm talking about in the video

 

Please do send a video but keep in mind I will be pushing around about 500lbs more than you

 

Couple videos here. Rpms on excel are a bit higher than I thought but it does not bother me. When I point the camera out the window that is to show that it's moving under its own power with just releasing the break pedal, no throttle.

Second video is a wot 2-3 shift to show shift extension. (Rpm drop after a shift)

 

you'll also have a 6l80e trans.
with a 4+ ratio 1st gear, you could put a soup can filled with vegetable oil in there and it would get off a stoplight.
If you don't understand how the converter works, then go with the recommendation from those who do like FTI, Yank, Circle D, etc etc

 

Similar to how a 4000 hard hit feels like a stock converter under light pedal in the new 8L90 cars.

-Dalton

 

Well, i think your questions are impossible to answer without knowing the specifics of your car, for example the valvetrain, final drive ratio, and how high you plan to rev it. I suggest you consult with one of the converter manufacturers on here (Yank, Circle D, FTI) and spec something out with that will fit your car and what you intend to do with it.

Just for reference, all the posts here are about 4000+, but most guys with stock GT gears and valvetrain tend to run lower than f-bodies, like 2800.

 

My new CircleD triple-disc 258mm has about 300-400 rpm drop between shifts.

It's a 3800. It's a little loose and I like it!!!

My old CircleD 278mm had about 1300-1500 drop. It was good but nothing like the 258mm.