tourqe converters

fordkid68 · 03-21-2002, 04:25 PM

ok I know they insrease exceleration. but how I mean I have no idea how they work. and what does it mean when they say 2400 to 2600 stall. and is it the higher the number the better. and how much do they really help.

thanks
ford kid

mean81GT · 03-21-2002, 06:43 PM

you ever sit at a light, and put your left foot on the brake, and your right foot on the gas? well, when you do that with a stock torque converter, the engine will rev to about 1800 rpm. even if you floored it, it will still only rev to 1800 rpm. in a mustang, when you floor it, of course it is going to spin the tires, and rev higher. but if you had 20 horsepower in the car, and you couldn't spin, it will only rev to 1800. the higher stall aftermarket torque converter puts the engine into the powerband quicker, by allowing the engine to rev free (to a point) of the tranny. so do they work? absolutely. but the higher is not the better in most cases. in a street driven car, a 2400 will suffice. i have seen full on drag cars with 6500 rpm stall torque converters. hope this helps.

PKRWUD · 03-21-2002, 07:23 PM

In short, the stall speed is the speed at which either the rear wheels will break loose, or the engine will stall. A higher stall speed means that you can get the engine rpms higher before launching. This is preferred when the engine is modified, and has a higher peak power band. For a stock engine, as mentioned, 2400 is more than high enough. Another thing to consider is the gears in the rear end. The lower the gears (higher numerically), the higher you want the stall speed to be. A mildly modified engine with 4.10 gears in the rear end should have a stall speed no lower than 2800.

Take care,
-Chris

mean81GT · 03-21-2002, 08:10 PM

I used layman's terms

PKRWUD · 03-21-2002, 08:40 PM

Quote:

Originally posted by mean81GT
I used layman's terms

And you did a fine job!!

Take care,
-Chris

fordkid68 · 03-21-2002, 08:47 PM

ok I get it now.

so are they just on automatic trans or can they be used on A manual trans to.

thanks I have I much better understanding now.

thanks
ford kid

PKRWUD · 03-21-2002, 09:15 PM

They are only used in automatic transmissions. They, for loss of a better term, do what the clutch and flywheel do in a manual tranny (transmit power from the engine to the driveline).

Take care,
-Chris

Rev · 03-21-2002, 11:03 PM

OK, here's my take on converters. As mentioned by PKRWUD, the converter functions like slipping the clutch in a manual setup.

When we go for higher power in a given engine, we almost always do it at a higher peak RPM. That means higher RPM torque peak (almost always). and a major loss in low end torque. This requires a higher stall converter (automatic) to get into the power curve of that engine. We need to compensate for that loss of low end torque. Lower gears help with the torque multiplication also, but it it is possible to have too low of gears and too much stall speed for a given engine/ car wt, etc.

The reason cars came with low stall speeds OEM is because they were biased towards low end torque and low RPM potential power. This made for good driveability at the expense of performance.
Performance engines usually require higher stall speeds with automatics.

Rev

fordkid68 · 03-21-2002, 11:53 PM

hey thanks guys I understand perfectly now. you did A good job on explaining it.

thanks
ford kid

mean81GT · 03-22-2002, 02:51 PM

my layman's terms sent it over the edge, didn't they??

fordkid68 · 03-22-2002, 03:15 PM

no they didn't. see when I said you guys did A good job of explaining I meant I got A good amount of information from every one your laymans terms explained thing the other post didn't (at least the way I interperted (sorry for the spelling) it. and the other post explainded things your didn't. in other words every post created A good team.

every ones post explained A litle bit and that litle bit turned into A lot.

thanks again. you all did A good job of explaining.

ford kid

03-21-2002, 04:25 PM	#1
fordkid68 Registered Member Join Date: Jan 2002 Location: fremont Posts: 306	tourqe converters ok I know they insrease exceleration. but how I mean I have no idea how they work. and what does it mean when they say 2400 to 2600 stall. and is it the higher the number the better. and how much do they really help. thanks ford kid

03-21-2002, 06:43 PM	#2
mean81GT Registered Member Join Date: Nov 2001 Location: NY Posts: 299	you ever sit at a light, and put your left foot on the brake, and your right foot on the gas? well, when you do that with a stock torque converter, the engine will rev to about 1800 rpm. even if you floored it, it will still only rev to 1800 rpm. in a mustang, when you floor it, of course it is going to spin the tires, and rev higher. but if you had 20 horsepower in the car, and you couldn't spin, it will only rev to 1800. the higher stall aftermarket torque converter puts the engine into the powerband quicker, by allowing the engine to rev free (to a point) of the tranny. so do they work? absolutely. but the higher is not the better in most cases. in a street driven car, a 2400 will suffice. i have seen full on drag cars with 6500 rpm stall torque converters. hope this helps. __________________ I'm a glutton for punishment.

03-21-2002, 07:23 PM	#3
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	In short, the stall speed is the speed at which either the rear wheels will break loose, or the engine will stall. A higher stall speed means that you can get the engine rpms higher before launching. This is preferred when the engine is modified, and has a higher peak power band. For a stock engine, as mentioned, 2400 is more than high enough. Another thing to consider is the gears in the rear end. The lower the gears (higher numerically), the higher you want the stall speed to be. A mildly modified engine with 4.10 gears in the rear end should have a stall speed no lower than 2800. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

03-21-2002, 08:10 PM	#4
mean81GT Registered Member Join Date: Nov 2001 Location: NY Posts: 299	I used layman's terms __________________ I'm a glutton for punishment.

03-21-2002, 09:15 PM	#7
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	They are only used in automatic transmissions. They, for loss of a better term, do what the clutch and flywheel do in a manual tranny (transmit power from the engine to the driveline). Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

03-21-2002, 08:47 PM	#6
fordkid68 Registered Member Join Date: Jan 2002 Location: fremont Posts: 306	ok I get it now. so are they just on automatic trans or can they be used on A manual trans to. thanks I have I much better understanding now. thanks ford kid

03-21-2002, 11:03 PM	#8
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	OK, here's my take on converters. As mentioned by PKRWUD, the converter functions like slipping the clutch in a manual setup. When we go for higher power in a given engine, we almost always do it at a higher peak RPM. That means higher RPM torque peak (almost always). and a major loss in low end torque. This requires a higher stall converter (automatic) to get into the power curve of that engine. We need to compensate for that loss of low end torque. Lower gears help with the torque multiplication also, but it it is possible to have too low of gears and too much stall speed for a given engine/ car wt, etc. The reason cars came with low stall speeds OEM is because they were biased towards low end torque and low RPM potential power. This made for good driveability at the expense of performance. Performance engines usually require higher stall speeds with automatics. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

03-21-2002, 11:53 PM	#9
fordkid68 Registered Member Join Date: Jan 2002 Location: fremont Posts: 306	hey thanks guys I understand perfectly now. you did A good job on explaining it. thanks ford kid

03-22-2002, 02:51 PM	#10
mean81GT Registered Member Join Date: Nov 2001 Location: NY Posts: 299	my layman's terms sent it over the edge, didn't they?? __________________ I'm a glutton for punishment.

03-22-2002, 03:15 PM	#11
fordkid68 Registered Member Join Date: Jan 2002 Location: fremont Posts: 306	no they didn't. see when I said you guys did A good job of explaining I meant I got A good amount of information from every one your laymans terms explained thing the other post didn't (at least the way I interperted (sorry for the spelling) it. and the other post explainded things your didn't. in other words every post created A good team. every ones post explained A litle bit and that litle bit turned into A lot. thanks again. you all did A good job of explaining. ford kid

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