Can I respectfully take exception to a couple of points?
First, I find it amazing that a 10 second car would waste a multi disc vig.!! I've been pounding the snot out of mine for well over 8 years now, and it still performs as well as it did the day it was new. Granted, I don't run a 10 second car, but still pound it pretty good with a mid/high 11 second machine.
As for not needing billet parts. I disagree, to a point. Once into the very low 12's or firmly into the 11's, there are one or two billet parts that are needed to negate the breakage that IS going to occur. The intermediate drum's input shaft in particular. It was the only way I was able to COMPLETELY stop my twice annual breakage. That and the planetary carrier.
I also find it strange that there are multi disc converters suffering "43%" slippage!! Or were you referring to singel disc units? If so, that I can believe.
Now that my regular heavy duty racing days are over, I certainly understand that I no longer need the strength of my multi disc Vig. but I certainly also WOULD NEVER run it as a daily driver on a non lock up converter. That makes no sense what-so-ever.
You can respectfully disagree. This is why we are here!
For the record, I am not bashing the Vig converter. It has proven to be a solid/durable piece. But, there are better converters out there. The "GSCA" train of thought is a bit anticquated at this point. OR, the "Red`s" way is the best way thinking. Red also did not use a Hemco upper plenum, until he was finally tired of hearing about it. He now uses one. Sorry to get off point...
You need to be outside the box sometimes to find what works best for you. The Vig never worked in my cars, so I found something that did.
The car in question did destroy the multi disc lock up clutches 2 (two) times. I understand your questioning this, but it is true none the less. The last time it packed the trans full of clutch dust/sludge.
And, as far as the billet parts, there are 3 high 9 second cars here that have no billet parts and an CPT converter. One ran for 6 years in this configuration. No parts failures. Whoever says they are necessary is MAKING those parts.
The shock load on the internals is significantly reduced with the non lock up converter. The drum may break, but with a non lock up... "usually" you are good. At least with what we are doing here.
Now, if you beat your car, on sticky tires on the street, and get alot of wheel spin... then hooking. You may/can toast the drum. But I have only seen that once on a drag radial car with a N-L. Many times with a locker.
I do agree the forward clutch drum (aka intermediate shaft) is a weak link. But, with a non locker, these failures are rare. With a tight lock up converter that is a different story. They can snap at the drop of a hat, I agree. Especially with an aggressive shift kit.
The 43% was not with a multi disc setup.
And, it makes plenty of sense to drive whatever converter YOU prefer.
You actually get more flow through a non lock up converter to help with the heat issue, due to their design. But, they will run a "little" warmer.
My choice is still a N-L.
Thanks for reading...
Brian