Does anybody in this group run an air dam with no rear aero? Specifically looking to see if there has been a noticeable change in fuel economy.

 

Cant comment on fuel economy, but did find a more than noticeable change in car balance/rear grip such that I toured the gravel trap on turn 1 after the front straight

 

Fuel economy, what's that!? (shrug) Well, since you ask, yes it will. Of more concern is getting the aero balanced, which usually means that of you do something at one end, you probably need to do something at the other end too.

Splitter? Airdam with no splitter will have less affect on balance than airdam with splitter. I suspect rascal was running both, and that would guarantee a visit to the gravel trap (or worse).

Plenty of info here, make yourself comfortable, and start reading.

 

I ran an air dam and no rear aero on the track at got 8mpg. When I added the wing I got 8mpg. Also, when I was running the car on the track without aero add-ons, I got ... 8mpg. HTH

Miatas have notoriously poor aerodynamics, so adding an air dam is likely to help with efficiency. Do it and let us know your results.

 

I'm running an SPM style airdam with 2" splitter, and BBFW rear spoiler. I started out with the spoiler in the lowest position, but had to raise it to ~24 degrees to balance the rear. I would expect no spoiler at all in the rear would be very loose.

 

That was actually the surprising bit. just airdam no splitter.

I was orig running a 3" splitter and rear wing, and took off the rear wing and cut splitter off flush to bumper lip so it was effectively just an undertray, and it was still really unbalanced. (causing several offs)
(Undertray was 12mm ply and still bowed upwards under car from downforce!)

I had to remove the undertray completely and then the balance returned..

 

Thank you all for the advice. The car will be run in endurance races and the goal is to make it about ~ 2hours before a fuel stop is required. During testing we will alternate between air dam and stock bumper cover configurations, pumping out after each session. I will dump some of the data here as we acquire it. We are running a stock 1.6 with a header and stock ECU.

 

That will be interesting information - looking forward to seeing it.

 

Please do, I would like to see this as well...