[DeTomaso] ZF-Q transaxle

[JDeRyke at aol.com]

IMHO the 'old' ZF is quite capable of handling 5-600 horses regularly and 
7-800 if the driver takes some care in shifting (and getting out of the throttle 
when airborn!) to prevent shock-loads. I know of two real ZF failures: Jr 
Wilson broke a clutch input shaft by not backing off while getting air-time at 
high revs/200 mph in his 572 inch Boss 429 conversion; the shaft snapped in two 
on landing. And Greg Isakoff somehow broke several gear sets in '04-05 while 
road-racing a 650+ horse Pantera; dunno how 'gently' he shifts. For the rest of 
us with less than $50,000 in our engines, a good tune-up of our ZFs wil allow 
them to do another 35 years on the street & occasional open track. Supposedly, 
the 'super' ZF gearsets are a little stronger- but I have no direct 
experience. 

I've not torn one down, but my understanding is, the Quaife LSD diff is based 
on the mid-'70s Torsen spiral-bevel-gear diff design (which I have torn 
down). These work well, as long as you get one that can take the torque. I have one 
in my garage right now that failed behind a 500+ horse 350 Chev in a 
roadracer. The iron diff case spread, allowing force to move outward to the tips of 
the bevel gears, which then chipped and failed. One problem seems to be parts 
availability;  when Torsen's patent (apparently) lapsed, the rights seem to have 
spread across the globe and not all dealers handle all models. I've checked 
four dealers & none can do anything for this particular LSD. Two had never 
heard of the model.
Nothings perfect, or cheap, when you talk of big power- and actually usie it. 
Torsen-type LSDs don't heat up lube like a clutch-type LSDs, so probably do 
not require any sort of diff cooler except maybe for Daytona or LeMans. FWIW- J 
DeRyke