Reply to Sub Bass Headache

Okay. I'm just gonna say it. I cannot get any decent sub bass in my songs! WHY!?

The last song I did, I had two layered basslines:

a) C3-C4 octave range, EQ'd from 40-80Hz using LF and HP filters.
b) C4-C5 octave range, EQ'd from 80~110Hz using LP and HP filters.

Sounded good on my monitors, burned it to a CD, took it in my car, popped it in (I have subs in my car). And guess what. Weak-ass bass!

Wtf is going on here!?

And, seemingly illogically, I song I did a few months back with one single bassline in the C3-C4 range EQ'd with about a +6.0db at 78Hz. And it slams. What the hell?

So here is my question really. What octave range do I want to use for the super sub bass? Obviously I'm believeing C3-C4. Any thoughts?