ephedrine in place of speed

[William_Again]

I was wondering I got all sorts of nasal decongestants around the house
and I heard that crushing them up and taking them (cause the contain
psuedoephedrine and a time release shell) can produce effects similar
to speed, but what I am confused about is first on the net some
websites have reported that you only need like 50mg of this to produce
the same effects of speed, but others claim you need like 300. I have
taken sudafed, crushed, at doses of 480mg (of psuedoephedrine) and felt
little of nothing...am I off on the dosage, do I have some sort of odd
tolerance considering I so rarely have done speed, or is this just not
possible?