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I don't even have an auto but can someone explain the stall speeds on different converters? What does 2000 stall mean, engine will cut out at 2k with the brakes on or the converter locks up completely at 2k?
Just Curious. Got no room in my CJ5 anyway.
Pigpen


 

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/wwwthreads_images/icons/smile.gif Piggy.......you are right on the money.....at Two Grand, the engine can no longer slip the converter, and if the tranny shaft were welded to a bridge rail for example the engine would pull down and quit. Having a low stall means you get closer to 1:1 earlier, and having a high stall gives the engine a chance to build up HP and RPM before you launch your rig. We have a TH 400 tranny, and I considered going to a very low stall converter thinkin that I may improve fuel mileage, but we reconsidered because we have a Quadra-Trac without the optional low-range gear assembly, and the torgue converter in this case has to act as our creeper gear.....through three miles of mud if need be......and we couldn't do that if it was a very low stall unit./wwwthreads_images/icons/smile.gif

CJDave
Quadra-Trac modified by the crack moonguy/wwwthreads_images/icons/wink.gif/wwwthreads_images/icons/smile.gif/wwwthreads_images/icons/tongue.gif transfer case team.
 

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hey there dave.. i have one of those low range units on a quadra trac here.. ill let it go for cheap.. since i will never use it.. pulled it outta the wagoneer.. was just going to save it incase someone i knew needed it... but i think you can just pull that unit off..

survival is instinct, but living takes guts
 

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/wwwthreads_images/icons/tongue.gif Hmmmmm..... that sounds interesting.....I can send you a blank-off plate to "cap" the QT unit. I wouldn't mind having one if it was in OK shape. They get real loose over time. E-mail me about this.....[email protected]if you have a minute to spare and we can talk bidness.......as they say in Texas./wwwthreads_images/icons/crazy.gif

CJDave
Quadra-Trac modified by the crack moonguy/wwwthreads_images/icons/wink.gif/wwwthreads_images/icons/smile.gif/wwwthreads_images/icons/tongue.gif transfer case team.
 

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one thing to keep in mind,

an auto tranny that doesnt have a lock up converter ( most older ones dont)
will never actually be at 1:1 ratio..

Ive seen numbers like 12% slippage at highways speeds in top gear..
its always doing what a torque converter does its "converting"

when I ran a tf727 I got a rebuilt converter, lowest stall lockup converter I could find.
It was nice, it moved the truck at idle ( 600 RPM in drive with 31 inch tires), and a quick blurp of the gas really lit the tires..

stock cconverters are usually 1000-1500 rpm
high stall converters might be advertised as 3000RPM, but it is really dependant on engine torque output..

these are for drag racing, so the engine is IN the powerband before Its ever moving the car..sand rigs might use a high stall, they are meant for going fast if you try and crawl with one youll waste ALOT of gas, and get things really hot, and then still probably have to walk home...


OzarkJeep
77 CJ5, in a bunch of sanded and primered pieces
 
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I believe I would phrase it a little differently.... Stall speed is nothing more than what you read on the tach, when you lock up the brakes, and apply full throttle. It doesn't kill the engine... It's just the maximum engine rpm you can get, when the trans is 'locked'. And, the other posts cover the reasons for 'higher' or 'lower' stall speeds. What you want, or need, depends on what you are trying to do. Obviously, a higher stall speed lets you get into a more favorable engine power-area, if you are trying to 'launch' well, as for drag-racing. Down-side.... You'ld be running in the 'slip' zone most of the time, at 'street-rpm's'. A 'low' stall converter locks up early, but hampers 'launching' capability, because the engine doesn't want to make much power/torque at low rpm's. 'Stock' works pretty good for most folks, even off-road, and in 'rock-crawling'. Like CJD suggested, it's a trade-off between 'slipping' (the equivalent of lower gears), and locked-up enough that you can live with it for other situations.

bobH
 
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No reason to not have an auto in a CJ-5. There are pleanty of them already running around. If you take a look at the 'installed' length, you will find that things like TH-350's and C-4's fit really well, and in some cases are actually shorter than some popular manual trans' (like a SM-465, or 420, for example). I am aware of one acquaintance that has a WWII flat-fender, running a TH-350, and he competed very well with it, in the Four Wheeler Top Ten Truck Challenge a few years ago. And, I believe you will find that the C-4 is a good 3 inches shorter than the TH-350, when installed, using AA parts.

bobH
 
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