1. are there different kinds of superchargers?(like turbos, different power ratings? etc?) and if so, how would you know which one to get?
Yes, there are different types. For example, read this page: [ http://www.hi-flow.com/super.html ] The "twin screw" superchargers they mention here seem
to be just perfect. Small, high efficiency, modern
design that should be very reliable. Unfortunatly because
of all that they're likely to be very expensive too... 2. everybody seems to think 2-4psi is the most you could get on an na's stock internals.
The one time I've seen someone post their dyno charts of
their supercharged NA, they said it was running 7 psi. So
I don't think you're limited to three or four. how do they know this? how do you know the max psi you could safely run? i dont want answers like "well, SC2+2 has one and he only runs 3psi max" is there a special way to determine when the psi is up to high (go till detonation i guess, then turn it down some, but wouldnt it be a little too late then?)?
Talk to a real tuner (maybe Jim Wolf) about this, but
my take on things is... The first fringes of detonation are not immediately
fatal. If you run the engine hard for a long time while
it's detonating badly, you will fuck up your bearings
and after some hours destroy the engine. But if you catch
it right as it's starting to detonate and IMMEDIATELY
rev the engine down, and don't do it again, you're
probably going to be okay. Detonation is usually caused by running lean. (I would
imagine it's possible to get it other ways, but usually it's leaning.) If you're tuning on a dyno, you can stick a
special O2 sensor up the tailpipe of the car and monitor
the richness or lean-ness of the mixture by how much oxygen
is coming out of the exhaust pipe. If the mix starts
leaning, you richen it up to avoid detonation. Again,
I don't know the details but I think this is a pretty
generally accepted procedure. Of course at some point the sheer amount of heat
produced by burning all that fuel and air starts to
overwhelm your engine. This is why it's important to
monitor the exhaust temperature too. 3. when people say the a/c must come out, does that mean the actual a/c (dehumidifying part) or just the cold air? what would happen if you put the a/c to, say, 65 degrees or less? would it just blow air?
Well, first of all, it's not that it's technically
impossible to keep the AC - it's just that it would be
very, very hard and nobody has managed to do it that
yet. At least not that we've heard of. The problem is that there's practically no room in the
engine bay. You pretty much have to take something out
in order to fit the supercharger in there. Over at Z32.org,
Anfernee has proposed some... "interesting" workarounds
to this problem, like running a long shaft from where the
drive pulley would be, back to the back of the engine
bay where there's (presumably) more room. He says
if there's room for two turbos AND a/c, there's room
for a supercharger and A/C. I don't really buy his arguments
in any kind of a practical sense. But in theory, you
could keep the A/C. Maybe you'd throw out the alternator
instead. Oh, er, wait maybe that's not such a good idea... ;] Incidentally, the dehumidifying and cooling parts of
the AC are the same thing. The A/C system is powered by
a compressor, which is essentially like the guts of
your fridge. Except instead of being powered by an
electric motor like your fridge, the compressor gets
spun by a drive belt from the engine. Outside air is sucked in, run across some metal pipes
that are filled with special coolant that has been made
cold by the A/C compressor, and the cool air then flows
into the cabin. Take away the compressor, and those metal
pipes aren't cold any more. And the air that comes through
your vents will never be colder than the outside air.
-Ben
Ben Cantrick, mackys@dimensional.com
Black 1994 TT. |
