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TQ converter upgrade for the TH125 by L44_87GT
Started on: 03-07-2004 01:38 PM
Replies: 9
Last post by: Solo2 on 03-15-2004 12:20 PM
L44_87GT
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Report this Post03-07-2004 01:38 PM Click Here to See the Profile for L44_87GTSend a Private Message to L44_87GTDirect Link to This Post
Anyone ugrade there tq converter on the 125.What are the results>

thanks

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Report this Post03-07-2004 02:11 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreDirect Link to This Post
Unless you are changing engines or doing major modifications, there is little if any benifit to replacing the TC in any unit with TC locking, like TH125C or the 4Txx series. GM is very good at matching the TC that will deliver the most torque for a given engine.

The belief that changing the TC always helps goes back to non locking units where the TC was a balancing act between torque and economy. A TC with high torque multiplier generally gets worse fuel economy and vise versa. The trick was picking a TC somewhere in the middle for production cars. Drag Racers would install units with higher multiplier since they cared more about hole shot than fuel economy.

This tradeoff is no longer needed. Once the car is cruising the TC will lock, eliminating nearly all TC losses associated with non locking units. That means the TC, when unlocked can deliver large multiplier and when locked delivers good fuel economy.

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Solo2
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Report this Post03-08-2004 07:19 AM Click Here to See the Profile for Solo2Send a Private Message to Solo2Direct Link to This Post
Hate to burst anybodies bubble but you can install a heavy duty high stall convertor from ProTorque.
www.protorque.com
1-631-218-8700

Part# PTCFZBB SS $395.00 plus shipping
Stall speed range = 2,500 RPM to 2,800 RPM

Raised my stall speed from the stock 1,700 RPM to 2,500 RPM which matches perfectly the 2030 cam profile. Many forum members are currently using this heavy duty high speed convertor. Excellant trans convertor to use for the drag - 1/4 mile strip. This convertor is the same one that are in the 4T60 trans also.
http://www.protorque.com/shopping/shopdisplayproducts.asp?id=30&cat=440T4%
2F4T60E%2F4T65E
PTC-FZBBSS
440 & 4T60E HEAVYDUTY
Approx Stall Speed: 2200 - 2800
Rated HP: UP TO 375 Price:
$395.00 plus shipping

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Oreif
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Report this Post03-08-2004 09:31 AM Click Here to See the Profile for OreifClick Here to visit Oreif's HomePageClick Here to Email OreifSend a Private Message to OreifDirect Link to This Post
Remember, stall speed is a factor of torque. The 440 and 4T60E are typically used with the 3800 engines which have a lot more torque than the 2.8L. So your stall speed will be different. The stock stall speed of a 1986 TH125 with a 3.08 final drive is 2100rpm. (Verified when they dyno'd my trans after being rebuilt.)
When I ordered my ProTorque, They set the stall speed to 2200 rpm. This was based on the torque from the engine dyno, final drive ratio, and tire size.

The difference between the stock converter and the ProTorque, Is I have less torque loss thru the trans with the ProTorque, as verified on the dyno.
Stock converter: 19.2% loss
ProTorque: 17.4% loss

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Happiness IS the corner.

[This message has been edited by Oreif (edited 03-08-2004).]

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Solo2
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Report this Post03-08-2004 10:47 AM Click Here to See the Profile for Solo2Send a Private Message to Solo2Direct Link to This Post
Oreif,
Just to let you know I used this info and read my converter ID tag and it was the second digit "F" code which relates to 1720 RPM. OGRE cave is the correct info to use. Sorry Oreif you are incorrect on this one. It happens sometime.

GM Torque Converter I.D.

The 245 mm dia torque converter I.D. code works the same way as the 298 mm converters, but with different meanings.



The first digit of a 245 mm converter refers to the application.

F = Front wheel drive
H = Rear wheel drive (except THM 180's)
S = THM 180

The second digit is the "K" factor. The chart shows the "K" factor for each code along with the stall speed. Note: Multiply the "K" factor by 11.6438 to get the stall speed of a 245 mm torque converter.

CODE K FACTOR STALL SPEED
A 240 2795
B 220 2560
C 205 2385
D 180 2095
E 160 1860
F 148 1720
G 140 1630
H 130 1514
J 177 2061
K 237 2760
L 163 1897
M 131 1525
N 218 2538
Y 122 1420
Z 203 2363

The third digit refers to the clutch type.

CODE DAMPER TYPE
0 No converter clutch
1 12O ft/lb
2 104 ft/lb
3 170 ft/lb
4 215 ft/lb Heavy Duty
5 215 ft/lb *RTC
6 170 ft/lb Heavy Duty
7 215 ft/lb *RTC Heavy Duty
8 Viscous Clutch
9 240 ft/lb
A 215 ft/lb
B 215 ft/lb *RTC

* RTC = Reverse Torque Control (poppet valve)

The fourth digit (optional) refers to the type of cover used.

CODE COVER TYPE (APPLICATION)
A FWD 208.2 mm Bolt Circle
B FWD 237.0 mm Bolt Circle
C FWD 237.0 mm Bolt Circle (viscous Clutch)
D RWD 247.65 mm Bolt Circle
E RWD 237.0 mm Bolt Circle, No Converter Clutch *
F RWD 237.0 mm Bolt Circle *
G RWD 247.65 mm Bolt Circle *
H RWD 247.65 mm Bolt Circle, No Converter Clutch *
K RWD 237.0 mm Bolt Circle, No Converter Clutch *
P THM 180 ISUZU
R THM 180 Opel
S THM 180 BMW

* 180 degree weld on each lug

Look at the code on the torque converter in figure 6. You can easily identify it as a front wheel drive model. (The first code is an "F"). The stall speed is 2760 (the second code is a "K"), and it has a damper assembly rated at 120 ft/lb's (the third code is a "1".) Notice that the fourth code has been omitted.

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Pyrthian
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Report this Post03-08-2004 11:32 AM Click Here to See the Profile for PyrthianClick Here to Email PyrthianSend a Private Message to PyrthianDirect Link to This Post
I am planning a Turbo, and want to stay with the auto trans. I was thinking a higher stall speed would help in reducing turbo lag also. Mostly looking for 1/4 mile times. I want to switch to the 4T60 also, so I was going to both at the same time - 2500 stall & 4T60. From the looks of that table Solo2 put out, there should be something stock to fit what I'm looking for. so would my best bet would be to find a Quad-4 with a 4T60 - being the 4 banger dual cam would probably have the highest stall rpm's? or - does just getting any 4T60 - and buying the protorque be the better way to go? Orief showed a 2% improvement in driveline loss, but I'm wondering if that the quality of the TC, or the higher stall rpm.
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Oreif
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Report this Post03-08-2004 11:34 AM Click Here to See the Profile for OreifClick Here to visit Oreif's HomePageClick Here to Email OreifSend a Private Message to OreifDirect Link to This Post
 
quote
Originally posted by Solo2:

Oreif,
Just to let you know I used this info and read my converter ID tag and it was the second digit "F" code which relates to 1720 RPM. OGRE cave is the correct info to use. Sorry Oreif you are incorrect on this one. It happens sometime.

GM Torque Converter I.D.

I'm not incorrect. I just looked at my stock converter and it's code "D". (FD3) Which means that each trans probably has a different torque converter based on application/final drive. My original 86 SE came with a 3.08 final drive with a 2095 stall (basically a 2100 rpm stall) Right now I have an 87 3.33 with the ProTorque 2200rpm.
Stall speed is still a factor of peak torque, Hence the different dampner types. If the engine creates more torque the stall speed is lower.
Basically the pessure generated by the turbines inside the converter is designed to hit full pressure at a given torque. An engine with a much higher torque will attain this level earlier in the RPM range. Hence lower stall speed.
So what year trans and final drive do you have?

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Oreif
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Report this Post03-08-2004 11:42 AM Click Here to See the Profile for OreifClick Here to visit Oreif's HomePageClick Here to Email OreifSend a Private Message to OreifDirect Link to This Post
 
quote
Originally posted by Pyrthian:

I am planning a Turbo, and want to stay with the auto trans. I was thinking a higher stall speed would help in reducing turbo lag also. Mostly looking for 1/4 mile times. I want to switch to the 4T60 also, so I was going to both at the same time - 2500 stall & 4T60. From the looks of that table Solo2 put out, there should be something stock to fit what I'm looking for. so would my best bet would be to find a Quad-4 with a 4T60 - being the 4 banger dual cam would probably have the highest stall rpm's? or - does just getting any 4T60 - and buying the protorque be the better way to go? Orief showed a 2% improvement in driveline loss, but I'm wondering if that the quality of the TC, or the higher stall rpm.

You can get a stock converter to have less loss. From what I understand, The stock converters have the turbine blades in the converter Only welded half way up the blades. This causes the ends of the blades to flex slightly under full torque/pressure. Many full trans shops will open your converter and weld the blades better to decrease loss. (Archie has this done when doing V-8's with an auto trans) Most aftermarket performance converters are more accurate since the blades are stronger and fully welded. Make sure when you get another stock converter that you also pay attention to the dampner factor. The wrong dampner level could make it worse. With ProTorque, You tell them the torque, final drive ratio and tire size and they set the converter up to match. There was no extra fee for having this done on mine.

[This message has been edited by Oreif (edited 03-08-2004).]

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82-T/A [At Work]
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Report this Post03-15-2004 11:49 AM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Direct Link to This Post
Don't know if this helps.. but I installed a Torque converter from a 1987 Fiero 4 cyl into my 1987 Fiero SE / V6. I did notice an improvement.... seat of the pants.. it feels like there's a little bit more of a "snap" off the line. I guess it allows the motor to rev up a tiny bit more before it engages. I've been driving it like this for 1,000 miles already, no problems.

I can also now peel out from a dead stop with the V6, I couldn't before. I believe the L4 torque converter has a 200rpm higher stall than the factory 6 cyl torque converter.

(I have the GX3 3.33:1 final drive).


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Todd,
1997 Pontiac Grand Am GT
1987 Pontiac Fiero SE / V6 (3.2L)
1984 Pontiac Fiero 2m4 SE
1981 Pontiac TransAm (sbc 350)
1973 Volkswagen Type-2 Transporter

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Solo2
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Report this Post03-15-2004 12:20 PM Click Here to See the Profile for Solo2Send a Private Message to Solo2Direct Link to This Post
Check the second digit on the conveter is the only way you can tell the TRUE stall speed. Anything else is only a guess.
CODE K FACTOR STALL SPEED
A 240 2795
B 220 2560
C 205 2385
D 180 2095
E 160 1860
F 148 1720
G 140 1630
H 130 1514
J 177 2061
K 237 2760
L 163 1897
M 131 1525
N 218 2538
Y 122 1420
Z 203 2363

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