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Discussion Starter · #1 ·
So I know a bunch of you all have auto transmissions lying around.

I'd like to gather some info on them.

The torque converters have a small stick with a barcode on them, usually on the backside against the transmission. If you guys can get me that, I can make a table and we can see what cars came with what.

So I need
Converter decal text
year of car
type of car
type of engine

This is more of an exercise in curiousity, but I just want to settle something once and for all.
 

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are you trying to figure out if the v6 and 4 cyl have different converters? I can tell you they do cuz the 4 cyl has a higher stall. :wink:
 

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Yes and i would like to know if a auto 3 speed from a 91 Lumina with a 2.5 cu. in. 4 cyl. will fit a V6, and if it has different gearing and stall. Only because i have one and it works great and am junking the Lumina soon and dont want to pull tranny out before it goes if it wouldnt fit the Z.

Also, on my Z, when convertor locks up on level under light throttle, the car speed is about 30 mph, is that normal? again wondering cause the Lumina doesnt lock up till i hit 45 mph.

One other thing, the Z shifts soft and quick from low to second gear, the Lumina is much crisper and a little longer before it shifts, which is much nicer, least in feel, anyone care to say how their Z shifts ?? (all original )

BTW i did try adjusting the kickdown cable on the Z, i could make it stay in low gear way to long, or back to like it was, no happy medium.
 

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Discussion Starter · #4 ·
easye said:
are you trying to figure out if the v6 and 4 cyl have different converters? I can tell you they do cuz the 4 cyl has a higher stall. :wink:
No kidding. :roll:

I want to put pen to paper with the actual #s

2.2 converter = 2375 RPM stall.

Got a v6 converter lying around? :wink:
 

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my 1990 v6 has an FJAB which is a 177K Converter.

the stall on those 177K's are roughly 2500-2600rpm with a hot engine, as measured by the engineers doing vehicle evaluations off the line @ Lordstown back in 1990-94.

Don't forget that stall speed is a factor of torque

K= (Stall Speed) / (Torque^.5)

so for a cold engine the stall will be around 2375rpm assuming 180ft-lbs @ crank .. for a V6

K factor for the 4 cylinders were 237.

so assuming 110 ft-lbs i think thats what most of the 4 bangers put out or close to it... the stall speed would actually be 2485 (cold engine) and obviously higher than the V6 with a hot engine.

Stall speed will increase with temperature.

Hope this helps clear things up.....or make things more confusing.

The difference between converters from 90-94 for v6 was 0. All converters were the same, only minor changes were made to the valvebodies for improved NVH and BSR issues.
 

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psquare75 said:
barrok69 said:
my 1990 v6 has an FJAB which is a 177K Converter.
Going by this

FJAB = V6 = J -- 2060 rpm

Mine

*Z** = I4 = Z -- 2375 rpm

http://www.gmtuners.com/gmtransinfo.htm

Worth changing while the tranny is out if doing a 3400/auto, I'd say.
I noticed on the site it says "approximate" stall.

I guess what i'm trying to say.... it doesn't matter what letter you have in your TC, it makes a Difference what engine its mated too. the K factor is the same for all *J** models...but the more torque you apply to it, the higher the stall rate is.

for example... going with the formula... which is more correct than anything.

My 3400 puts out 193 ft-lbs to the wheels. assuming 20% loss in transmission, that makes it ~230ft-lbs @ the crank.

so 177 = X / (230^0.5)
X = 177 * (15.165)
X = 2684rpm stall

So i don't really see the need to go to a bigger stall converter

using a k=237 converter from a 4 cylinder would achieve a stall of 3594rpm !! say hello 4mpg city.....

and im not sure how credible the information on that site is anyways.

The information I provided was from the actual engineers that calibrated and validated these things for a living.
 

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Also, on my Z, when convertor locks up on level under light throttle, the car speed is about 30 mph, is that normal? again wondering cause the Lumina doesnt lock up till i hit 45 mph.
These are programmed values in the ecm. They're generally based on vehicle weight and gearing along with the engine's torque curve. Most older cars lock up below 40 although the Lumina is a lower torque / greater weight combination and might really have problems with the low speed lockup.

Wanna sell the TBI injector for that Lumina?

The information I provided was from the actual engineers that calibrated and validated these things for a living.
I've never seen this. How / where did you find it?
 

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slowolej said:
Also, on my Z, when convertor locks up on level under light throttle, the car speed is about 30 mph, is that normal? again wondering cause the Lumina doesnt lock up till i hit 45 mph.
These are programmed values in the ecm. They're generally based on vehicle weight and gearing along with the engine's torque curve. Most older cars lock up below 40 although the Lumina is a lower torque / greater weight combination and might really have problems with the low speed lockup.

Wanna sell the TBI injector for that Lumina?

The information I provided was from the actual engineers that calibrated and validated these things for a living.
I've never seen this. How / where did you find it?
I worked at the GM Windsor Transmission plant :D They made the 3T40/TH125C. I have a large stack of binders and notes that have quite a bit of information from the engineers that developed the calibrations for those valvebodies, transmissions, TC's.

You'd be surprised in the difference in just the valvebody alone from one year to another. same overall transmission, but lots of subtle improvements are made over the years in service.
 

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I worked at the GM Windsor Transmission plant
Cool.

I have a large stack of binders and notes that have quite a bit of information from the engineers that developed the calibrations for those valvebodies, transmissions, TC's.
Very cool!

You'd be surprised in the difference in just the valvebody alone from one year to another.
Ahhh... wish I could say I would. I was a GM tech for a number of years while GM was trying to improve out the non E transmissions. I've got pages and pages of updated part nos and service bulletins for many transmissions. It kind of sucked, because you might try changing a valve and spring to improve a 1-2 shift feel and end up with shift timing all skewed. It took a lot of time to come up with combinations which felt ok on the first try. Gotta say, they finally got it "not too bad" the last few years they were building that trans.
 

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My Lumina? well i just yesterday got the Z inspected, next week tags. The Lumina will be retired then, i was planning on stripping it and keeping what parts would work on the Z and scrapping the rest, not sure yet though. May keep it over winter as it does still run, drive it every day,
For awhile i may keep it as a back up in case the Z needs to be down for awhile or something.
Here in Md where i live, i dont have to reinspect a car that i had on the road if i need to relicense it, just transfer tags again, which is so much easier than trying to start off on another car and inspection and so on.And its good to have a backup car.
The Lumi would never pass inspection again without a lot of $$$
It now has 260K on it, the engine doesnt smoke one bit, leaks at rear crank seal though. Tranny works flawless. But the body is going, dented from winter driving, its a work car..
But if i decide to scrap it, id part with what parts wont fit the Z. Will inform on board here if i do.
 
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