RE: PN - Radiator ground wire upgrade - part deux

[QSHIPQ@aol.com]

Hope to get all the archive in on this one in terms of response.  A couple of 
things come from a myriad of private posts:

-  On high speed the fan is audi spec'd at 500w divided by 13.2v = 37.8 amps. 
 That asssumes that all the wiring is perfect, from source to ground.  60 
amps is minimum, anything less, you could blow out early, causing an 
undesireable overheat condition (not necessarily a fan problem) which easily 
blows a head gasket.  For archives sake, I TOTALLY, ABSOLUTELY, POSITIVELY 
RECOMMEND an 80AMP FUSE, since the factory chose this for some obvious 
reason.  
-  Dual 30amps could work, but remember, more components to wash down with 
salt and water (see next addendum), or just plain fail.  If one fuse gets 
weak you lose both.
-  Grounding to chassis.  Good idea maybe as a complementary ground, not a 
replacement ground (please reread this).  The reason it feeds back internally 
is that a crappy ground washed with salt and water in the engine bay, makes 
for a crappy ground.
-  Fusing the positive side instead of the neg.  A couple of problems, 
usually positive side fusing blows spiked amps sooner than neg side fusing.  
Regardless, you are trying to prevent all pos to neg crossover.  The problem 
is a frozen fan crossing pos to neg, addressing the neg is safer for the 
harness, the pos could still lead to overheat sooner (and whacking the neg 
with ANY pos feed is bad), but it will most likely prevent a fire under the 
hood.
-  3 bux on a fuse.  Better than nothing...  Maybe.  I personally convince 
customers to spend more money on this than 3 bux, and all the parts to 
convert I listed by audi won't cost as much as you think.  A 3bux 'fix' could 
actually cause a 1000USD+ head gasket blow you may not get by putting nothing 
in there at all.  See above.
-  The minimum fuse can take a maximum toll.  Bad connections to the fan can 
suck up a lot of resistance.  

REMEMBER:  The gains are saving your harness and preventing a potential 
underhood fire.  The offset is that a blown fuse means NO FAN OPERATION, 
period.  Bottom Line:  Do this mod, but do it right.  IMO, you put in the 
audi 80amp fuse correctly on any audi chassis, you don't have to guess on the 
diagnostic when she blows.

Hope this helped address all the privates.

whew....

Scott Justusson
QSHIPQ Performance Tuning
QSHIPQ@aol.com
'87 5ktqwRS2 -20vt
'84 URQRS2 - 20vt
'87 4Runner turbo