Torque converter info
Printed From: West Coast Fieros
Category: General Car Chat (Not Fiero Specific)
Forum Name: Car Talk thats not a Fiero
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URL: http://www.westcoastfieros.com/forum/forum_posts.asp?TID=2145
Printed Date: 29 April 2025 at 12:21am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com
Topic: Torque converter info
Posted By: Dr.Fiero
Subject: Torque converter info
Date Posted: 25 October 2010 at 4:01pm
This might be relevant to a Fiero at some point, dunno... but it looked like good info so figured it should get archived.
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You can tell which converter you have by a 4-digit alpha code found on a sticker attached to the converter.
* DGHG = stock '94+ Impala converter
* DBCF = '86 'vette converter
* DBLF = '95+ L35 S10 truck converter
The code is interpreted as follows:
* 1st Digit: Transmission application
o D = 1984-1/2 and up 700-R4, 4L60, 4L60E
o C = 1984 and earlier 700-R4, 200-4R, 200C, 325-4L
o B = 250C, 350C
* 2nd Digit: K-factor (stall speed)
o K = K-85, 1211 rpm
o G = K-100, 1397 rpm
o F = K-110, 1611 rpm
o E = K-115, 1654 rpm
o B = K-140, 2025 rpm
* 3rd Digit = Clutch and Damper assembly
o C = ? (stock '86 'vette)
o H = ? (stock '94+ Impala)
o L = ? (stock '95+ L35 Vortec S10 truck)
* 4th Digit = Rear cover
o C = 3 lug round
o D = 3 lug round
o E = 6 lug
o F = 3 lug square
o G = 3 lug square
Going to the S10 converter increases stall speed by 628 rpm, which feels
very good indeed. The factory 2025 rpm converter is an excellent, low
cost upgrade that offers a very noticeable effect on performance without
being too radical.
One area that some of the better (and more expensive) high stall
aftermarket converters will excel in is durability in high HP
applications. While the stock converter can live behind 300 to 350 HP
with few problems, going to 400 HP or more can be pushing it. Actually
in my experiences the trans will go before the converter, unfortunately
when the trans goes the debris usually takes the converter with it (of
course the opposite is also true).
Originally, the '85-'86 Corvette torque converter was recommended as an
Impala upgrade. As you can see from the 2nd digit code this is a K-140
converter, which is the highest stall factory converter available for
the 700-R4, 4L60, and 4L60E transmissions. The original part number for
the '85-'86 'vette converter was #8650919, which was later changed to
#24201203. GM only sells torque converters as what are called
remanufactured units, but depending on the converter application you
order, you may actually get a new converter instead of a rebuilt unit.
Unfortunately since the '85-'86 'vette is an older application, you will
almost certainly get a rebuilt converter if you order under that part
number. Not only will the converter be used (rebuilt), but since then
some of the internal components have been upgraded.
To get the high stall converter in an updated form with the latest
design, order a similar K-140 high stall converter from a 1995+ 4.3L
(RPO L35) S10 Truck V6 application (p/n 24202310). This new converter
uses the same basic internal components (stators, etc.) as the 'vette
converter, and as such has the same high stall speed rating (2nd digit
code "B").
GM ranks converters by what they call a "K-factor", which indicates
torque capacity and the resultant stall speed. Mark McPhail of GM
Motorsports says both the '95 L35 Truck and the '85 Corvette converter
described here have the same K-140 internals, resulting in the same
stall speed given the same engine torque output. Since stall speed
varies with engine torque, GM gives a rating of 2025 rpm, however this
converter stalls at around 2200 rpm in a stock Impala.
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