TCC lockup - which scheme would give better performance?

[Bruce Plecan]

-----Original Message-----
From: Roger Heflin <rah at horizon.hit.net>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Saturday, January 09, 1999 1:23 AM
Subject: TCC lockup - which scheme would give better performance?

Don't lock the TCC under full throttle!.
The TCC is much softer than the other clutches in the tranny to prevent it
from chattering.  I've gone thru 4 or so tranny overhauls in my 700R4.  Last
guy said ditch the TCC, and you'll never break it again.  Well put 50,000
on it, and it's still alive.  Cording to him what kills the 700's 4L60's is
the
TCC fllaking off and contaninating the fluid, and at a microscopic level,
getting embedded in the other clutches, and then they fail so like the 3-4
clutch problem is really caused by the TCC.  I will admit, that I'm hell on
trannies,
with all the calibration testing I was doing, but going to a non-lock up
converter was the best tranny money I've spent.  If you don't drive hard
often, or mileage is your primary concern ignore the above.
  Also, comparing the 700 to the GN 200 isn't a good comapro in my book.
The 200 as installed in a stock gn is light years ahead of stock 700, in
my opinion.  Very early in the gn program, it was looked at to haul 4
guys with misc hardware at WOT in pursuit situations.  The 700 was
never really successful at that, from what I've seen/heard.
  Bruce


>Ok,
>
>I have pretty much disassembled and deciphered the TCC lockup code,
>and I feel I can add some code for a TCC lockup scheme, but I don't
>want to go to the trouble of adding it if it won't help.
>
>Without code changes (only data)
>
>The current lockup occurs at 95 mph, which is way down in my rpm range for
my engine,
>about 4400 before lockup, 4000 after lookup.  I am going to change this so
that it locks
>up just before the end of the 1/4, somewhere around 105 or so.
>
>No code change required for this:
>The second choice is to lock it up at say 76 in second gear and let it
stayed locked
>through 3rd also.
>
>Here is the scheme that requires code adjustment:
>
>The third choice is to lock it at 76 in 2nd, unlock it in the lower rpms in
3rd and lock
>it back up just before the end of the quarter in 3rd.  The idea is to get
the engine more
>quickly through the lower rpms,
>and lock the converter at the best moment to keep things around the
>power band.  76 mph in 2nd puts me just a bit higher than my HP peak.  The
locking before
>the end of the 1/4 is because the car lurches pretty hard when the
convertor locks, and
>currently after it lurchs the engine hits low rpms and more slowly
accelerates.
>
>I know the GN guys had some schemes, are they similar to what I have and
which one worked
>the best?
>
>I am also considering more serious code changes, such as adjustments to
allow less fuel to
>be injected in 1st and 2nd to get a more optimal mixture.
>
> Roger
>