trans stall speed

[oka065]

G/Day all, I hope Easter went well. Can someone tell me the stall speed for the 4L80E. Also what is your cruising speed with 3.73 gears.

Cheers

Rod

[arrowheadracing]

My stall speed flashes to 2200 rpm from a dead stop if I stand on it ( accelerate hard ) , if I roll into it , it will flash to 2500 rpm. I always thought this was high, but since max torque is around 2400, its probably just right.

[oka065]

Yeh well I think the guys I bought my engine / trans package have supplied me with the wrong torque convertor as my stall speed is about 3000-3500 rpm.

cheers

[DA BIG ONE]

Originally posted by oka065:
Yeh well I think the guys I bought my engine / trans package have supplied me with the wrong torque convertor as my stall speed is about 3000-3500 rpm.

cheers Converter stall speed will always be higher when engine produces more than stock torque, and lower on an engine that produces stock, or lower than stock torque.

Beside "stall speed" converters have what is called a "torque ratio".

Torque converter ratio is best defined as a multyplier, example; 2.0:1 ratio will increase the engines torque output 2 times just before tires break traction from a dead stop. As soon as forward motion starts this converter ratio increase quickly takes a dump. Dyno pulls are needed to determine what engine torque output is at this point.

A good torque converter builder will be able to tinker with stall speed and torque ratio of converter.

[ace58]

Please correct me if I am wrong, but I recall putting a torque converter/transmission combination from a diesel into a 350 gas years ago before computer control and there was no stall speed to the converter at all. I plowed snow with the truck and had to change to a stock converter for a gas engine to allow engine to turn high enough rpm to make power.

It was explained that a diesel engine starts making torque just off idle. This seems to make sense given with the transmission in drive, it moves without a lot of throttle input.

[whatnot]

When my transmission went out last year, I talked to a lot of transmission shops and they all said there is only one torque convertor (same for both gas and diesel) for a 4L80E (at least for a 1995 truck)

[Dimsdale]

Actually, according to the Hydramatic 4L80E Technician's guide, there are two torque converters used with the 4L80E: a single stator version, and a double stator version. The double has greater torque multiplication, somewhere around 3.5:1, while the single stator version has a ratio of 2.1:1.

There is no information about what truck gets what torque converter though, but I would guess that the single stator version is used in our trucks for the most part.

[Dimsdale]

Found further info on the torque converters (from a tranny rebuilder website):

For this series transmission there are five different possibile torque converters. When rebuilding your transmission it is always recommended that you change the torque converter. When ordering the torque converter you must supply the four digit code off of the existing unit (located on sticker). The possibities are:

Torque Converter Installation/Preparation
Code Order Part Number Application
152, 492, 494, 528, 576, 606, 670, 671, 675, 841, 4L80-1, 1991-up 454 Gas engine, 6.2L Diesel engine, low stall: single element stator

8676526, 8674193, 8682604, 8685-366, 4L80-2, 1991-up 5.7L 350 engine, high stall: dual element stator

8685407, 8674198, 4L80-3, 1993-up 4.3L Truck, Van high stall, single element stator

0827, 0829, 4L80-4L, 2000-up 5.7L, 6.5L, 7.4L low stall, single element stator

364, 830, 0831, 0825, 4L80-4H, 2000-up 4.3L, 5.7L, 6.0L, high stall, single element stator


What we need is the old "switch pitch" converter used on TH-400 transmissions between 1965 and 1967 (or for you fans of really old tranny tech: the variable pitch stator introduced on the 1955 Buick Dynaflow transmission).

[DA BIG ONE]

Originally posted by Dimsdale:
Found further info on the torque converters (from a tranny rebuilder website):

For this series transmission there are five different possibile torque converters. When rebuilding your transmission it is always recommended that you change the torque converter. When ordering the torque converter you must supply the four digit code off of the existing unit (located on sticker). The possibities are:

Torque Converter Installation/Preparation
Code Order Part Number Application
152, 492, 494, 528, 576, 606, 670, 671, 675, 841, 4L80-1, 1991-up 454 Gas engine, 6.2L Diesel engine, low stall: single element stator

8676526, 8674193, 8682604, 8685-366, 4L80-2, 1991-up 5.7L 350 engine, high stall: dual element stator

8685407, 8674198, 4L80-3, 1993-up 4.3L Truck, Van high stall, single element stator

0827, 0829, 4L80-4L, 2000-up 5.7L, 6.5L, 7.4L low stall, single element stator

364, 830, 0831, 0825, 4L80-4H, 2000-up 4.3L, 5.7L, 6.0L, high stall, single element stator


What we need is the old "switch pitch" converter used on TH-400 transmissions between 1965 and 1967 (or for you fans of really old tranny tech: the variable pitch stator introduced on the 1955 Buick Dynaflow transmission). Amen!

For those of you with deep pockets there are some builders who will do a custom billet converter w/multi disk in kevlar for lockup.

Have really deep pockets?, then the tranny can be had to handle 1000+ HP/TQ.