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Converter question- Sprag or Spragless?

 
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MufflerBearings69
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1968 Ford Galaxy

PostPosted: Mon Jun 14, 2010 1:42 pm    Post subject: Converter question- Sprag or Spragless? Reply with quote

Can someone give me a quick synopsis of which is used for what?

I see them advertised both ways and a modest price increase for spragless but cant find a clear answer as to which is for what.

Also, did someone on here have a Redneck Performance converter? If so, would you buy from them again?

Thanks for the help.

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clay
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PostPosted: Mon Jun 14, 2010 2:59 pm    Post subject: Reply with quote

Quote:
A critical part in any converter is the sprag, or even the lack of one in a spragless converter. The sprag holds the stator in place as the converter multiplies torque. This happens as the converter turbine (finned housing splined to the input shaft in front of the stator) gains rpm and catches up to near the speed of the converter impeller/pump (shell of the converter and fins attached to the rear half of the housing, behind the stator). Once the speeds near equalization, the fluid flow path actually changes inside the converter, and the sprag now allows the stator to freewheel with the fluid flow. In a spragless converter, the stator is always held in place, and its slight restriction to the fluid flow path change will cause a bit more heat to be generated, and thus a less efficient converter (as compared to the same converter but with a sprag).


I have heard it is pretty much reserved for really high hp cars. Also heard they will run pretty hot on the street. Reading the above description it sounds like it will not be quite as efficient as a sprag converter but I guess when you get around the 1500 - 2000 h.p., you have to give up something to make it live. I haven't had any experience with spragless but for a street car, personally I wouldn't consider it. Clay

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MufflerBearings69
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PostPosted: Mon Jun 14, 2010 8:39 pm    Post subject: Reply with quote

Bingo. thats what I needed to know.

Thanks!!

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Mr.T
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PostPosted: Mon Jun 14, 2010 9:53 pm    Post subject: Reply with quote

MB69
We have used a Redneck converter for 2 seasons-3500 stall and it really made our LUV truck come alive. 383 with CCC cam 195 AFR's
and it turned a best of 10.73 @ 121.29. The next run blew a rear end.
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10sec.et
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PostPosted: Mon Jun 14, 2010 11:08 pm    Post subject: Reply with quote

i run a Redneck and so does Adam. the spragless is for high HP applications in the range of 1000+. Redneck suggested i DO NOT run a spragless on the street. didnt really get into the why. i figured they know more about converters than i do Confused . anyway, i dont intend to use anyone elses converter after buying theirs.
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af2
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PostPosted: Tue Jun 15, 2010 12:40 am    Post subject: Reply with quote

Even on 1000+ hp the spragless is a dog for mph.

Funny, the guys running a Redneck like them! They are very smart on setups.

Even funnier,,, You don't see BS on forums about them. Good people!!
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Paul P
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PostPosted: Tue Jun 15, 2010 12:56 am    Post subject: Reply with quote

Right Adam! thumbsup
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Big Dave
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PostPosted: Tue Jun 15, 2010 2:26 am    Post subject: Reply with quote

The sparg is the one way ratcheting clutch inside the converter that allows the stator to do what it is designed to do; multiply the engines torque. The only reason to run an automatic is to take advantage of the torque multiplication that occurs as the saturator is spinning at less than the front pump speed (as they get closer together in speed the sprag allows the stator to free wheel reducing drag and improving the efficiency of the tranny).

Without the sprag the efficiency drops in the tranny (parasitic losses go up and the fluid will get hotter). You will not loose all of the torque multiplication but the drop in efficiency will offset the gains so you are in effect driving around with a fluid coupled clutch that never locks up and weighs a lot more than a clutch mechanism would. In my opinion a Lenco planetary would be a better choice than a spragless torque converter. If you can not afford a Lenco, build an old school crash box four speed manual transmission.

The company that invented the spragless converter said it is only used them on one thousand horse plus race cars that have a problem with tire shake during burn outs and upon launch off a transbrake if wheel speed isn't high enough on launch (a fairly narrow market segment in my opinion).

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Skunkworkx
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PostPosted: Sun Jun 20, 2010 9:06 pm    Post subject: Reply with quote

Running a Redneck 4000 9" and only got 3 runs on it...blew a head gasket Sad Never really got the car to hook plus hot and humid day.
On the street it felt pretty good though Smile

On the street no one recommends spragless that I've heard of.

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clay
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PostPosted: Sun Aug 29, 2010 1:38 am    Post subject: Reply with quote

Got a little more information about this subject to share. I acquired a converter that is a really nice piece but is a spragless setup. Took it by Torque Converter Services which originally built it for a 2800 lb. car, 565 c.i., horsepower application. Talked with Cameron (one of the nicest, most helpful guys you will ever meet) about how it would work for my setup as I think my current converter is going to be too loose. Anyway he pretty much builds most of his race converters spragless anymore and said in testing the difference is minimal. One of his tests consisted of changing 6 converters at the track in the same day. Two of the converters were identical other than sprag vs. spragless. Only difference was 1 m.p.h. on a car running low 11's (it was a super stock Chevelle running a 325 h.p. 396 c.i. class). He did say there are race applications that will benefit from a sprag - usually something with not a lot of h.p. that can't keep pulling down track and lets the converter start to couple up. He said unless slippage gets under 10%, the sprag won't do anything anyway because the stator wouldn't turn if it had a sprag. He even said if I was just driving from stoplight to stoplight (short trips) he would leave mine spragless. However I have to go 30 miles to get anywhere so he did say it would get too hot whereas the sprag would give a better fluid path at cruise and reduce heat.

Quote:
The sparg is the one way ratcheting clutch inside the converter

Actually the ratcheting setup is a mechanical diode. He didn't have a lot of good things to say about it either - said it is about as strong as the best sprag setup but costs more. I know this will add to the confusion - so glad I could help Laughing . Clay

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