Experience with twisted inputs needed

Blacksdieselhp said:
If your twisting these stock sized shafts, then there is something going on in the tranny that shouldnt be. All the top trucks in pro street are running stock sized inputs and none of us have had any problems. Ours is three years old. We run a stock intermediate as well. I think Phil Taylor said his was 2 years old. As well as Darren Morrisons. We are all in the 1.30-.140s 60ft and WAYYYYYYYYYYY over 1000p. Even in my 4wd race truck, over 400 passes on a sonnax input and its still going strong today at 100hp.

I am tempted to start doing a guarantee on our trannies for twisting or breaking inputs, because we just dont ever see it. Most of the secret is in the vb setup. But there are other things that contribute to the failures as well. Big shafts are just a bandaid for an underlying problem.
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Are you at the 4500lb limit for prostreet? Also what kind of torque does a nitrous motor make?
 
I pulled a few 25 psi launches (with a single 80FMW) on my truck last week, stock intermediate and output (47RH) with a TCS input (regular 300M). only reason it probably stayed together is the lack of traction or the fact that its around 5800 lbs

and my VB shifts HARD
 
Blacksdieselhp said:
This is the #1 cause of failed shafts. Not many people have figured out how to build a smooth shifting vb with no bindup that holds clutches.
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I think your exactly right it is the shifts that kill them and not so much the launch. If you have to get the shift timing right so there is no bind plus if you soften the shifts some the clutches take the hit more and save the shafts. Another thing that I have found that has helped my transmissions is when I started running slicks on my truck. The slicks have a more constant bite and don't load and unload like a street tire on the track . That's extremely hard on shafts.
 
Blacksdieselhp said:
This is the #1 cause of failed shafts. Not many people have figured out how to build a smooth shifting vb with no bindup that holds clutches.
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have you looked inside a revmax VB ..... interested on your throughts on their dual spring setup ...... the lockup port is sometimes drilled smaller as well .... to reduce lockup pressure

btw - about to send you a pm
 
How many of you guys with standalone/pcs setups have broken shafts? What about with manual vbs?

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Material data:

Material:.................................300m VAC-ARC Alloy.........Aermet 340 Alloy

Yield Tensile Strength*:..................248,500 psi.........................314,000 psi
Ultimate Tensile Strength:.............295,000 psi.........................352,000 psi
Elongation at Break:.....................10.5%................................11.3%
Reduction of Area:.......................33%...................................55.2%

(*)-Yield occurs when material has stretched .2% of total length. Considered safe limit before material is permanently deformed.

Both should be heat treated or at least annealed coming off the CNC to alleviate work hardening and subsequent weakening.
 
Blacksdieselhp said:
This is the #1 cause of failed shafts. Not many people have figured out how to build a smooth shifting vb with no bindup that holds clutches.
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Funny when I here the local boys talking about how well they can build a trans. They have no idea on a good quality shift.
 
Losing 700lbs over the winter has taken any twisting that we did have right out the equation for us this season. Made our best pass ever at the Edmonton NHRDA event 9.41@152mph @ 6000lbs.
 
I sold the standalone/pcs setup and ordered a another aermet input. Also considering a goerand manual vb. What vb are you guys running that's breaking/twisting shafts? Or what else do you think would cause this? I want smooth.

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Nitrouskix said:
I sold the standalone/pcs setup and ordered a another aermet input. Also considering a goerand manual vb. What vb are you guys running that's breaking/twisting shafts? Or what else do you think would cause this? I want smooth.

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sorry to be off track, but can i get some more pics of the truck in your avatar? :Cheer:
 
Runninlean said:
hope you got rid of the lever or your going to likely keep having this problem.
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What lever do I need? I have not fixed the trans yet, just getting parts. I will not be using the previous trans builder this time.

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dvst8r said:
losing 700lbs over the winter has taken any twisting that we did have right out the equation for us this season. Made our best pass ever at the edmonton nhrda event 9.41@152mph @ 6000lbs.
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Boogity boogity BOOOOOGITY! About time you guys put that thing on a diet.
 
The trans in my truck now, shifts as smooth as a stock one, and I have at least 60-70 passes on this one, it is the TCS 300M shaft. My last trans shifted really firm and almost acted like it was binding, and that one broke 3 shafts from 3 different mfg.

I also have the aermet shaft in the tool box for next round.
 
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