Hypermiling/aero mods

[Drew99GT]

Have any of you guys tried doing basic aero mods to your vehicles, like a partial grill block? From what I've read on the hypermiling forums, most people get an honest 3-5% improvement in fuel mileage from just a grill block.

Think I'm gonna try it! Yup, it'll look ghetto, but my hood is already dented.

I refuse to go with cardboard wheel covers though.

 

[Schmoe]

I wouldn't. Especially where I live in the summer time. Overheating an engine will cost more than a mere 3% savings in gasoline.

 

[daves66nova]

cover up a little at a time,then you shouldn't have any problems and you will know where to stop.

 

[Schmoe]

until your stuck in unforeseen circumstances....again, a chance not worth taking IMO.

 

[speedyswede]

Topic of external mirror delete here.

In the interest of saving fuel it seems worth while....but the alternative of mounting tiny dome mirrors inside the car just doesn't seem safe to me. I need my big external mirrors to see.

 

[daves66nova]

If it starts to go over the normal temperature,just pull over undo some of the blockage and you're set,no problems.It doesn't have to be a permanent blockage

 

[MrCritical]

To pass Louisiana yearly safety inspection, all factory standard equipment must be in place, and functional.

That would mean the mirrors would have to be where they were originally mounted from the factory and functional.

 

[Drew99GT]

AHHHHHHHH, I love having a beater. Whats a couple small drill holes in the bumper. The lower grill opening is massive. I might cover some more up as well. I'll definitely leave the top opening open. Don't worry, she's already got a dented hood.

There was a Car and Driver article about fuel mileage enhancements back in 74 during the gas crunch - in their testing back then, a partial grill block actually provided less aerodynamic drag than a full one - resulting in around 5% gain in fuel economy.

The grill opening on my car is massive - even with the amount of blocking I've done, the entire rad is still in the air path. This just covers up parts of the front subframe and radiator support.

I'll track mileage and report back.

 

[Drew99GT]

Next up: cardboard wheel skirts and a huge whale tail.

 

[rpn453]

I have a small opening at the top, and a large one at the bottom of my car. I cable-tie a flat black piece of thin plastic (from a crazy carpet) over the large one in the winter as a partial winterfront. It may be coincidence, but my best highway mileage does seem to occur in spring when I still have that cover on. It's cut to the same shape as the grill so nobody seems to notice it unless I point it out.

 

[DmanWho]

I just learned that my 4-cylinder SX4 is officially a "gas guzzler." (I can't believe it has come to this!)

I'm up to trying some stuff... Already made a slight 'CAI type' intake change, some exhaust mods (

), a lighter/smaller UD pulley, tried fuel additives and various fuel brands, tire pressure near max (43psi), reset ECU to learn "putting around town" mode, and not being the designated driver (that was good for 1 MPG

).

Our SX4's 25 MPG on 10% Ethanol is above the average for the "city" style driving we do.

 

[Audi Junkie]

There are 4 "teeth" or openings in the front bumper of the CRV. I covered to outboard ones, as well as the lower half of the lower grill. It cleans the facia up a lot. I used black corrogated plastic, so it is not just invisible, but looks better than original, being smoother. I thin there is a lot of room for improvment on most cars.

I'm not the least bit concerned about cooling. In fact we've been seeing the temp guage bottom-out while coasting. I might cover up more in winter.

ftr- we're getting the best mpg ever.

 

[02Pilot]

A couple points:

- I would think that you might see more aero improvement (though perhaps only marginally) by covering the upper opening completely, and perhaps some of the lower. Looking at race cars, their openings to feed air to the radiator(s) are generally very low, right above the splitter. I suspect (though this is only speculation) that improving the flow over the hood is more beneficial than smoothing the deflection around the bumper.

- Another aero trick that seems to show benefits and is quite unobtrusive is to place small, stiff plastic tabs (maybe an inch or two high) directly in front of the tires (picture very small mudflaps, but hanging in front of the tires). This diverts the air away from the tires, which are a substantial drag contributor. Some cars (my BMW, for one) have these from the factory.

 

[Drew99GT]

02Pilot, that makes a lot of sense. Further covering will be forthcoming.

 

[BrianWC]

Just PLEASE don't end up doing this:

 

[Drew99GT]

Just wait...

 

[eljefino]

he could do that to the chevy van in the background.

 

[Drew99GT]

Looks crummy - I think some black paint is in order, at least for the top grill blocks.

 

[02Pilot]

I would consider pulling the grill and fabricating a block to fit on the back side. The depth of those slats is not going to cause serious disruptions at any speed where aero actually matters, it will look a lot cleaner, and you won't have nearly the potential for annoying whistles from air leaking past all those edges.

 

[Gary Allan]

cardboard template folded in half. Trim to fit all the angles and the center moniker. Unfold. Cut material of choice to match ..or make another one and use cardboard (the waxy stuff) as real air block. Spray to match exterior color. Replace as needed.