Hi BOATMAN10 and Welcome to CDF:
I have two answers for you. The first answer assumes you need to break the program into segments. The second says "just burn as a data disc".
I use Nero 7 Ultra which contains a Wave Editor. There is a 27 day trial period. If you only have this project, Nero will work. I'm sure there are freeware downloads of just wave editors but I'm not familiar with any.
Whatever program you use, open the full MP3 File and copy paste the sections you need into new files.
As goatroper asked, are you able to play MP3 in your car?
When you set up your burn, select DATA disc as your burning option. That will preserve your MP3 format and you should be able to listen to approximately 7 hours of audio on your CD. You're probably thinking you can only get 80 minutes but that's if the disc is burned as an AUDIO CD.
If you burn as a Data CD, you may still want to break the single file into smaller segments so you can advance to different tracks. If so, see answer one. Also note that Wave Editors have timelines so you don't need a formula. You can see the actual time of a recording from the start to the end.
P. S. I asked a Moderator to close your other thread as this one should have been "bumped". It's a technique where you can move your thread to the top by adding a post. If this happens again, go to your thread and enter "bump" in the new post.
There are a number of audio guru's who regularly visit CDF. They've probably been away but they are likely to have other thoughts as well.