yeahhhh. so last week I added a 99 spec wing to my fd I left it in the top least drag position .


this week I decided out of curiosity I wanna see what effect it has on my MPG's so today I put the wing in the second to last setting . and went to a friends house who lives about 30miles from me , on the highway doing 80 my normal cruising speed i noticed something OFF ... I was cruising at 9 inches of mercury /vac rather then the usual 8.

-.255 on the commandcer vs usual -.237


I thought ok maybe I have a tail wind . so on the drive back same thing same -9 in

This is weird as I thought adding downforce/drag should reduce my mpg/s and increase the load on the motor , Not lessen the load.

I will do more tests next time see if there is a difference in MPG's

But for hte mean time anyone wanna chime in with an explination ! ?? LOL

 

Did you install the wing backwards?

 

nah no lift LOL

car is noticeably more planted at highway speeds

 

Less turbulence at the rear? I have no idea, actually...

 

I don't think it was the wing, personally. I think it was more likely your foot was just a /64th lighter on the gas during that drive. -1inch vacuum isnt really a significant statistic.

If I were you (and I could be bothered to do this) I would repeat the runs with and without the wing and see if the differences are consistently repeatable.

Its just such a small variance, I don't believe the wing is the culprit :p

 

The night before I went to a car show that is right next to that same friend's place and i was eyeing the the vacume and was in the -8's

and then the next day i did almost the same route to his house with the wing at the angle and I got the -9 inches results haha , but I will be going for a test drive tonight after work. lets see what happens . I tried yesterday but was carblocked by miami traffic.

 

That is really interesting, and I am not going to say you are wrong because you are the one with the statistical data, please keep us in the loop. and one inch of vac is roughly 12%.
I am picturing this in line with the pick up tail gate vs gas mileage question. Open vs closed vs off vs cargo net.

 

In theory, a wing increases the coefficient of drag. It's using the airflow to produce downforce. The stock numbers on the FD show a different cD between base and R1 models.

You could have had a tailwind, been going slightly downhill, any number of things can account for that difference.

Dale

 

I will , and honestly I'm skeptical because well It makes no sense But atleast it gives me something to do!

 

yeah tailwind was my first thought , but I got the same results going the other way so I should of gotten a head wind. unless the winds changed and gave me a tail wind in the span of 2 hours

Wind god following me around to help my mpgs? LOL

 

In short, you need more data. One test with so many variables isn't going to provide much of a conclusion. I think it's safe to say that given a controlled experiment, the wing will add drag which will require more fuel consumption for the same speed.

 

correct !

 

My theory is that at night your car was under more electrical load, and therefor more engine load. You need to do back to back testing with all the same conditions to prove anything.

 

Theory was prettmuch disproven yesterday . seems like the wind was with me i was getting 8 inches going one way , and 9 going the other with the wing set in the same position I didnt get a chance to change it .

But I did make an observation , the difference in injector duty was quite a bit .

1 inch difference made a 4% injector duty difference 21for 9inches , and 25 for 8 , this is at 15.7-16 afrs , and when i tailed a semi truck , Not so close it was dangerous . at the same speed of 80 mph I went to -12 inches of vacume and about 17% injector but it was running much richer in the lower 14 afr's

 

Cd data exists from Mazda for each of these wing angles. Higher Cd is higher drag, no ifs and or buts.