[Curculio]

Since modern cars and vans are typically designed in a wind tunnel (real or virtual now, I guess)to maximize efficient air flow, the alteration of air flow over the front of the van by a bug deflector may have an affect on gas mileage, just as adding a cargo carrier on top does. Has anyone noticed any change in gas mileage with a deflector? Any change in handling in a high wind situation?

 

[Walt43]

I didn't notice any change in mileage after I installed my air deflector. I still get about 18-19 mpg(driving 30% highway, at least). On an interstate trip to upstate NY I got about 24-25 mpg, which is the same as before. I do notice that most of the bugs now hit the windshield about halfway up instead of all over. There was one time a big rock from a dump truck hit the deflector when I was on the interstate, and it only put a little scuff mark on it, so it saved the paint. I minor annoyance is that leaves can get caught between the deflector and hood, so I need to spray a hose in there every once in a while. As far as handling, no difference. In high wind situations I do hear a bit more wind noise at highway speeds, though. Here in NJ it's a help in the winter because a good portion of salt spray now hits way up the windshield when highway driving, so I have to use the window wash much less. A cargo carrier has the problem of increased drag in the front and increased vacuum in the rear, so it really affects mileage.

 

[Maugham]

I suspect that you are right that changing the outside shape of the vehicle affects mileage. Each of the add-ons would undoubtedly decrease mileage, however so slighly. When you add up the effect of each gizmo, the net effect may be significant.

No driver is going to be able to tell the difference in mileage on a van with or without, say, mud flaps, but a wind tunnel and sophisticated equipment can definitely tell.

Officially reported mileage is very important in selling some cars, particularly minivans. 1 mpg really can mean a lot in terms of marketshare and price, hence the pressure to cut as much wind resistance as possible.

I think this is just one of the reasons such features as mudflaps and dooredge protectors are optional. The standard vehicle gets tested and rated with the least number of external options. What the consumer does after that doesn't affect the offical mileage rating.

IMHO, anyway...

Regards,

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Maugham

"I plan to live forever. So far, so good"
'02 RP EX-L due 10/17
'85 Prelude that we'll keep!
'01 Ninja folding aluminum scooter
'00 New Balance Model 658 Shoes w/ '01 White Laces

 

[Intrepid175]

<font face="Verdana, Arial" size="2">Originally posted by Curculio:
Since modern cars and vans are typically designed in a wind tunnel (real or virtual now, I guess)to maximize efficient air flow, the alteration of air flow over the front of the van by a bug deflector may have an affect on gas mileage, just as adding a cargo carrier on top does. Has anyone noticed any change in gas mileage with a deflector? Any change in handling in a high wind situation?</font>

Hi Curculio,

I've made two 2500+ mile trips from the Houston area to Muncie, IN and back since I bought my '01 LX. One without the deflector and one with. "On the road" mileage ranged from the mid to upper 24's to the very low 26's on both trips. My "round town" mileage is very similar to Walt43's, in the low to mid 19's for the most part and that is also with 30 to 40% highway driving per tank.

FWIW!

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Drive Safe,
Steve R.
'01 SS LX
Cargo tray, leather steering wheel, mud guards, alarm, fog lights, transmission cooler, in-dash CD player, Kelton subwoofer, under seat storage tray.

 

[ody]

IMO, the deflector would have insignificant effect on mileage. I agree it would probably be detectable in a wind tunnel with sensitive measuring instruments, but not on the highway. There are so many variables with regards to mileage, unless you have something like car top carriers you aren't likely to notice a mileage decrease. Besides the deflectors are quite aerodynamic in their design. Biggest drawback I've seen in past applications is cleaning underneath them as Walt43 mentioned.

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