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12:46:11 - 04/26/2024
Dakota Performance
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Dakaty
Dodge Dakota
10/17/2001
20:02:17
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 Subject: Stall Speed
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OK.. who understands the ramifications (SP?) of changing out the torque convertor to modify the stall speed?
The following LENGTHY article is from crankandchrome.com (an interesting web site)
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HIGH PERFORMANCE CAM VERSUS STOCK TORQUE CONVERTER
All too many enthusiasts screw up here, so listen up. In any street-driven, automatic transmission vehicle, when picking a cam, match its bottom power curve to the torque converter's stall-speed. Stall-speed is the rpm the engine increases to when you put your left foot on the brake pedal and your right foot one-third or more on the gas pedal. Most factory V8 engines in the 350 cubic-inch area have a smooth-idle camshaft and a 1,700 rpm stall-speed torque converter. 280 to 305 cubic-inch engines may have a slightly higher torque converter stall-speed of 2,200 rpm. What you do not want to do is install a performance camshaft with a nice lopey idle that starts making power at 2,500 rpm. The tightness of the 1,700 rpm stall-speed torque converter may not allow the engine to idle properly. But here's the real problem: Stab the throttle from a dead stop, and you're going to witness one slow engine from 1,700 rpm to 2,500 rpm. Why? The cam overlap/duration reduces compression and the engine takes time to get going. An identical car with a stock cam is now one car length or more in front of you. Then at 2,500 rpm, the cam hits its bottom rpm power-producing point and it starts pulling like gangbusters. But now the other car is four lengths in front. At the finish line, you've made up three lengths but still lost by one. Now, go to your favorite transmission shop and buy a 10- or 11-inch diameter, 2,500 rpm stall-speed torque converter ($200 - $250) and have it installed. Now when you nail the throttle, the engine revs immediately to 2,500 rpm and it keeps on going! It feels as if the car has 4.11:1 gears! Adjust your timing to come in around 3,000 rpm and adjust the carb's secondaries for 2,800 rpm or so and now you're going to blow the rear tires right off the car if you're not careful. With good traction, you'll now put three car lengths on an identical stock vehicle and another car length by the eighth mile. He'll never catch you. Summation: In an automatic transmission-equipped vehicle, the most important "combination" is at what rpm the camshaft starts making power and the torque converter's rpm stall-speed.
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It seems that this may be a very good performance modification for us "auto guys"??? Does anyone have any feed back or experience?
Sorry for the long post.
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Quikbear
Dodge Dakota
JOIN HERE
10/23/2002
21:25:02
| RE: Stall Speed
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Yes. True stall,which can only be achieved with a transbrake,should be 700 to 800 rpm less than the rpm at which the engine reaches it's peak torque.If you have made modifications which raise the peak torque curve.then a high stall converter is a must for off line acceleration.
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Mike Nicosia
Dodge Dakota
JOIN HERE
5/02/2003
22:55:23
|  RE: Stall Speed
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I have read so much on stall converters I am more confused then when I started. What would be the best converter for me? 52 Chevy Bel air 350ci torque honed engine block 0.40 overboard. Piston (flat top) 9:1 compression. Camshaft Performer 422" lift intake, 444" lift exhaust, .050 degrees duration, 204 degrees intake, 214 degrees exhaust. Crankshaft .010 undersized rod and main bearing journals, balanced rotating assembly. estimated 325 hp. 3.73 rear end 350 turbo hydromatic chevy transmission. Heavy duty clutch, currently 1700-1800 stall converter with a shift kit. I still can't come close to spinning the tires even after changing rear end from 2.60 to 3.73. Any suggestions would be appreciated. Mike
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slopehead
Dodge Dakota
JOIN HERE
5/03/2003
10:13:35
| RE: Stall Speed
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Message:
First problem is the bowtie.............
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gg
Dodge Dakota
JOIN HERE
5/03/2003
13:41:28
| RE: Stall Speed
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Message:
get amopar
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FazDak
GenII
5/03/2003
15:52:06
| RE: Stall Speed
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Message:
Damn Mike!! Im not one to flame much but why in the hell would you come to a Dak site and ask that kinda advice?
You realize theres about one million Chebbie forums?!!
Being a "car enthusiast" thought I will tell you this and anyone else who wants to know.
You can call or write any one of the major trans/converter manufactures and give em your specs, they will be the most qualified to reccomend you a stall and size for your application.
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