I made this partial exhaust channel deflector a few months ago, but wasn't motivated to post about it yet. That deflector is 1.5" tall if I remember correctly, was originally planning on .5", but that just looked way too tiny.
I had been planning undertray flow management for a while, but just recently I actually DID something about it. In a page far past, (page 8 to be exact) I posted this picture on my plans for flow management. It helps to have some point of reference, as my real picture is not the best.
Pro tip: Don't try to bend one piece of coroplast into an aerodynamic shape, like a bowed out V or U. It doesn't work. Instead, merge two pieces together so you can get the
point across better.
I mean really, you would think I would know this crap by now. I guess not.
Just recently I have started my long highway commute again, but much more frequently this time, so lots of driving!
I am pretty sure the deflector has made a difference, as I am pretty much always able to coast to a certain point in the highway while keeping the speed at or above 55. Before it was a crap shoot. That has certainly helped mileage, but I didn't have any record trips this tank. In fact, I left the grille block on too much and the fan ran a lot, hurting mileage a bit. On other tanks I have managed to have almost exclusively my highway commute on them, this tank was not like that. I had both my highway commute and work commute in this tank, and I still reached a
new record tank of 38.9 MPG!
Pre-heating the engine helped reduce the impact of my much shorter commute on the tank mileage, while the deflector improved coasting just a bit so I could coast over hills where I wasn't always able to. My departure times are flexible(when I can tolerate it.
I just want to go home!) and I can definitely optimize my departure times to avoid ridiculous traffic.
So, that being said, my next mileage update will hopefully be the shattering of another one of my goals: The 40 MPG tank.
Happy modding!