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Author Topic:   Torque convertor slippage.
gahainsey
Dirt Full Roller

Total posts: 43
posted January 23, 2003 07:17 AM
I am considering replacing my powerglide with a stick. My question is what percentage of RPM is the stock powerglide convertor slipping at 5500 RPM. The amount of slip will affect final gear selection. Any experience?

racer17j
Dirt Forum Champ
Total posts: 1565
posted January 23, 2003 01:22 PM UIN: 54865418
most guys i know run the same gears with a glide as they do with a stock 3 speed

Flatlander
Dirt Freak

Total posts: 310
posted January 23, 2003 04:59 PM
If your trannie is built right and maintained I don't think you have any slippage in high gear I'm sure you may have alittle jumping on it back on the straits but I never noticed my tach jumping once it was wound up

dirtracer7
Dirt Maniac

Total posts: 106
posted January 23, 2003 09:53 PM
If I remember right from tranny classes a converter hooks up about 90%.Newer cars and trucks have clutches in the converter so they can hook up 100% .

Flatlander
Dirt Freak

Total posts: 310
posted January 23, 2003 11:19 PM
that's interresting dirtracer7 I never would have thought the slippage would be that high but thinking about it I guess it has to have some and this is probably the cause for a lot of the heat

gahainsey
Dirt Full Roller

Total posts: 43
posted January 24, 2003 06:51 AM
The 'slippage' actually causes a torque multiplication. It is not necesarily a bad thing. I'd just like to put a number to it so that a revised final drive can be calculated.

powerglides
Dirt Full Roller

Total posts: 69
posted January 24, 2003 07:03 AM
Torque converter slippage is variable it depends on horsepower, rpm, and bite. but even a stock unit should not make more than 200-300 rpm difference. This is where all the heat in an automatic comes from so run a cooler.

dirtracer7
Dirt Maniac

Total posts: 106
posted January 24, 2003 09:50 AM
The heat is caused by the fins cutting through the fluid (shear).Thats why its not recomended to run a higher than stock stall converter for a truck that plows snow.I have a Dodge snow comander factory plow pakage the trans cooler is about 2/3 the size of the radiator.

gahainsey
Dirt Full Roller

Total posts: 43
posted January 24, 2003 09:53 AM
Thanks. Maybe I will post an update once the season starts. I may not even change the tranny. I wish I could find an 8 inch convertor that stalls around 1500. A small diameter convertor would have a smaller moment of inertia than an aluminum flywheel and stock clutch!

powerglides
Dirt Full Roller

Total posts: 69
posted January 24, 2003 12:57 PM
Coan sells a 10" low stall converter but its $475 why don't you run a dummy converter?

gahainsey
Dirt Full Roller

Total posts: 43
posted January 24, 2003 01:24 PM
"must have operational torque convertor" is the biggest hangup. I don't know if they would catch one with an internal dump valve body or not.

glen73
Dirt Roller

Total posts: 25
posted January 25, 2003 08:53 PM
here in oklahoma,a lot of guys have been running Bushore Trannys,they have the internal valve,no extra pedal,just put in high gear and once car gets going drop it low,nobady ever got cought with em,you can get a 10" dummy converter from Coan that will wash some hot fluid in so the converter will be hot like a working one

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