Convrter Question

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cgarb
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Convrter Question

Post by cgarb » Mon Jun 01, 2015 4:40 pm

Is there any ET to be gained from switching from a sprag type converter to one with a mechanical diode in a footbrake launched drag car? All else being equal just a sprag type change.

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woody b
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Re: Convrter Question

Post by woody b » Tue Jun 02, 2015 6:41 am

No ET change. A mechanical diode is supposed to be stronger than a "regular" sprag, but functions the same.
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Re: Convrter Question

Post by F-BIRD'88 » Fri Jun 05, 2015 8:42 pm

I think you are refering to a "spragless converter" comparted to a normal converter"

Spragless converters are generally used in very light weight cars. it is stronger as there is no sprag clutch on the stator to fail.
It is slightly less efficient as the stator is locked all the time. Its in "stall mode" all the time
on a pass. Generally for light weight dragsters and light weight super gas cars.
generally very reliable and consistant ET but a slight hit on trap MPH and best ET performance. Ok where you can ET faster then you really need to to be competitive.
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On a foot brake "heavier" car you generally want a converter with a functional sprag. its more efficient. The car ets and MPH s a bit quicker.
If you are breaking the "sprag" (stator sprag clutch) on your torque converter you are probabily doing the burn out wrong.
A abusive burnout is hard on the converter and hard on the 2nd gear sprag on a th350 and th400.

Never dry hop test the tires for traction , after a burn out. Do the burn out then pull up directly to stage the car. A "dry hop' tire test. Kills the traction on launch and eats the converter sprag. Never do a 2nd gear only burnout. Use all the forward gears on the burnout.

When you stage the car your last motion must be a forward motion while in forward gear.
DO not shift the trans into neutral- then back into gear after staging the car.
Especially on a Chrysler torque flite. This is how a trans explodes on launch.
Your last car staging motion when staging must be a forward motion IN gear.

This sets the sprag in the converter. Failure to do this is pure driver abuse and will result in converter sprag failure and or 2nd gear sprag failure.
Wheel HOP also kills a converter sprag and drive shafts, and differentials too.

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Re: Convrter Question

Post by cgarb » Sun Jun 07, 2015 4:14 pm

Nope, not interested in spragless. A mechanical diode is a different type of sprag. They are suppsed to be a tougher sprag than a conventional one. I havent broke a heavy duty sprag yet but i was interested in if it would make for faster et's.

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Re: Convrter Question

Post by Alan Roehrich » Sun Jun 07, 2015 8:34 pm

cgarb wrote:Nope, not interested in spragless. A mechanical diode is a different type of sprag. They are suppsed to be a tougher sprag than a conventional one. I havent broke a heavy duty sprag yet but i was interested in if it would make for faster et's.

A sprag either holds or it doesn't. A different sprag won't make you faster.

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Re: Convrter Question

Post by cgarb » Mon Jun 08, 2015 10:56 am

Ok then, thank you. Question answered, its not worth the money upgrading if i dont have any trouble with what i have.

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