Author Topic: Torque Converter Stall Selection  (Read 1859 times)

Offline harcorshe

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Torque Converter Stall Selection
« on: October 04, 2017, 08:04:36 PM »
I'm in the process of putting everything together, but I need help selecting the stall range for a torque converter.  Here are the particulars:

1978 K20 - Chopped to Shortbed
14 Bolt - 4.10 w/ Truetrac
33 inch tires
454 .20 over
9.3:1 compression
440Hp @4600RPM
535ft/lbs @3800RPM
Comp Cam 11-234-3 Hyd. Flat Tappet
212/218 @.50"

Just looking to drive to Home Depot--but I want to beat you there...

I'm thinking something in the 1600 to 2000 range?

Thoughts?

THANKS!


'78 K20
454
TH400
14 Bolt
205 Transfer Case

Offline VileZambonie

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Re: Torque Converter Stall Selection
« Reply #1 on: October 05, 2017, 05:21:16 AM »
I think you need to add a zero in front of your decimal points unless you really went all out :o

.50" = five hundred thousandths of an inch
.050" = fifty thousandths of an inch
.005" = five thousandths of an inch
.0005" = five ten-thousandths of an inch

Okay class dismissed. So are you guesstimating your HP/TQ #s or did you dyno the engine? What transmission are you running? Tell us more about your setup, carbureted? Cylinder heads & valvetrain setup, intake, exhaust?

So far it sounds like the stock converter will be fine.
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Offline harcorshe

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Re: Torque Converter Stall Selection
« Reply #2 on: October 05, 2017, 07:43:36 AM »
Good catch! Yes, I should have added a zero. Twenty thousands over on the block.

The engine was put on a dyno so those are accurate numbers.

More particulars:

TH400
Stock 049 Head ported and with larger valves
Holley 670 CFM w/ vacuum secondary
Air Gap Intake
Sanderson Shorty Headers

I called a couple of places and had one person recommend a 1350 stall, and another recommend a 2300.

Thanks.
'78 K20
454
TH400
14 Bolt
205 Transfer Case

Online 1967KaiserM715

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Re: Torque Converter Stall Selection
« Reply #3 on: October 05, 2017, 08:50:01 AM »
Pretty simple, a torque converter stall tries to keep the rpms in the power band. I'm not an expert, but if you power climbs fast then starts to level out I would look for a low to mid level stall, say 1300-1700, especially with the 4:10's. If it had higher gearing (lower numerical) a higher stall might be more beneficial.

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Offline VileZambonie

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Re: Torque Converter Stall Selection
« Reply #4 on: October 05, 2017, 05:40:38 PM »
Is the trans in place? How does it drive now? You're still pretty much in the ballpark of running a stock TC.
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Offline harcorshe

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Re: Torque Converter Stall Selection
« Reply #5 on: October 05, 2017, 07:00:39 PM »

Thanks Kaiser!

The trans is out. Just got the engine back and thought I would investigate whether it made sense to upgrade the TC before putting everything back together. I've no idea what kind of TC is in it now. I would assume stock.

Based on what I've learned from asking a lot of questions and calling various vendors, I'm considering an 1800. Sound about right?

Thanks.
'78 K20
454
TH400
14 Bolt
205 Transfer Case

Offline VileZambonie

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Re: Torque Converter Stall Selection
« Reply #6 on: October 06, 2017, 05:30:00 AM »
So the engine is a fresh rebuild but the trans you didn't do anything to. How did the trans work before?

The advertised stall rating of the converter is typically a middle number at which you can expect it to stall. The TC is multiplying torque in its initial phase so performance torque converters are geared toward helping take advantage of this which aids in launch. They also quickly reach the coupling phase ideally at your peak torque rpm so you will notice a difference in the way your engine rpm responds to acceleration which you may or may not like for normal street driving. So when you modify an engine drastically it is a good idea to utilize a tc that follows suit. Your modifications are not drastic so you can still use the factory converter.

From what you've described as your setup and intended use, that stall rating will work however you may want to consider this. If you've not yet run the engine and the trans is still in its existing state untouched or unknown, run it, see how you like it and then assess if you need a different stall rating to meet your need. As of right now you do not have a baseline to go off of so you either way it's a decision you need to make, do you alter it now while it's out and see if you like it or address it after? Either way a 1200-2000 advertised rating will work. Good luck with your decision.
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Offline harcorshe

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Re: Torque Converter Stall Selection
« Reply #7 on: October 06, 2017, 11:01:48 PM »
Excellent explanation and great advice. Plus I just might save myself a few bucks! Thanks for taking the time. I really appreciate it.


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'78 K20
454
TH400
14 Bolt
205 Transfer Case

Offline Engineer

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Re: Torque Converter Stall Selection
« Reply #8 on: October 09, 2017, 06:05:09 PM »
I had a 2800 rpm converter behind my 396. I liked that combination. The 396 wasn't anything special. Driving down the highway you couldn't tell much difference than the stock unit.

I personally think you would be happy with something in the 2500 range.
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Offline 75gmck25

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Re: Torque Converter Stall Selection
« Reply #9 on: October 20, 2017, 08:31:53 AM »
I've seen a lot of recommendations in other forums for cars to use something in the 2500 rpm range, but the vehicles usually have a more aggressive cam than 212/218 @ .050, especially in a 454.

You probably don't need a 2500 stall, but it should give you some good power off the line, and be fun to drive to Home Depot.

Brice

Offline harcorshe

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Re: Torque Converter Stall Selection
« Reply #10 on: October 24, 2017, 10:17:29 AM »
So, just to update, I went with a Hughes Performance 1800 stall. Now if I can just get the engine to line back up with the mounts I can get this project put back together and stop occupying all three garage spaces...winter is coming....
'78 K20
454
TH400
14 Bolt
205 Transfer Case