How much will a brush guard hurt FE?

[IsaacCarlson]

I have a brush guard I want to install to keep deer out of my engine bay and headlights. How much FE can I expect to lose, if any?

[comptiger5000]

While I'm not really sure, I would think that as long as it isn't wider than the current front end, the FE penalty would come mostly from the added weight.

[IsaacCarlson]

good to hear....It is pretty light but strong. I can easily pick it up and set it on the truck by myself.

[RobertSmalls]

I bet it will have a pretty large impact. The top five streamlines in this image pass over the car pretty much unmolested. If you stick some large diameter tubing in their path, Cd will increase. I'd imagine that the impact would be smaller on streamlines that are going to pass through a radiator or under the car, though.

Cylinders have high drag. Ellipses have lower drag, and streamlined bodies have the lowest drag. But you're not really interested in fairing each of the tubes of your bully bar, relative to the wind as presented to each tube, right?

[IsaacCarlson]

been thinkin about it......but it won't stick up much if any.

[KamperBob]

Originally Posted by RobertSmalls

I wonder about center line only wind tunnel pix. It's just a 2D slice of a 3D problem. The one center is not at all representative of what happens at both sides.

As for the OP question, the brush guard may do very little damage. The rest of the vehicle has a lot to do with cleaning up the wake. I would worry about nose shape last.

My 2c
KB

[IsaacCarlson]

That's kinda the rule I have been using.....back-to-front. I figure if it does hurt a little FE then it is ok because a deer in my engine bay would be $$$$ to fix. This brush guard is my own insurance policy.

[stevet47]

Those brushguards don't do squat for deer. The general consensus that I have heard many times is that they actually make the damage worse.

[RobertSmalls]

I don't mean to belabor the point, but since I straightened out my twice-crashed front end last week, lean burn has been so much easier, and my FE has been 5-10mpg better. If you are okay with okay aero, then by all means, install it.

Originally Posted by RobertSmalls

...fairing each of the tubes of your bully bar, relative to the wind as presented to each tube...

There's a much easier way. Basjoos' fully enclosed custom deer deflector, which doubles as a grille block:

http://aerocivic.com/imgs/front-3-4-z.jpg

It would also give you the opportunity to get those awful square corners off the front of your truck.

[Frank Lee]

Originally Posted by stevet47

Those brushguards don't do squat for deer. The general consensus that I have heard many times is that they actually make the damage worse.

Similar to what guys racing the old Porsches discovered: impact damage was usually easier to repair when they'd removed the bumpers, as the damage tended to stay more localized instead of being spread throughout a larger area of the chassis.

Well, you already have it. If you've been keeping a good gas log perhaps it will reveal a difference... and perhaps not.