Jay2therescue your just on top of all my questions thank you
What about nitrogen gas if you fill your tires with that will I get some improvement or is that just to keep my tires at a constant pressure

Drive it smart aero mods will probably be the best gains in mpg for you and the wai.

Nitrogen tire filling is just to keep someone else's wallet full. There's nothing to gain. In fact, the biggest purported benefit is that nitrogen can't seep out through the porosity of the rubber; but if that's true then with air already being 78% nitrogen any seepage will be the remaining 22%, so you only have to top it off a few times before it's probably over 90% nitrogen.

In a race car it might make a difference, but a regular car driven in regular traffic will never have any sort of difference.

I agree. There is not really any advantage to having Nitrogen in the tires of a street vehicle.

ok so I went and built a fuel vapor system and I hooked it up right on the intake manifold there was a spit sticking out of there so I took the tab off and routed my hose there to connect it it is a 4in abc pipe 1 foot long... I tested it with out and I was getting between 16 to 17 mpg and after I installed it I went for a 10 mile test drive at 95kms and reset my mpg computer and at the end of the 10 miles it hit 19 mpg

when I first bought the truck it had 94000 kms and my first tank it only did 14 mpg after a few tank fulls it went up to 15 mpg .. I bought a fuel max chip from flebay and my next tank
and from then on in I've been averaging 17.1mpg

not sure how to put pics on here tho to show you

pics of my system
 

I hope this works foe getting my pics on here