Thoughts on Fiberglass Rear-Skirt Design

[stevey_frac]

Ok, So... I've yet to do anything major, not even as much as a grill block (but if i can get my hands of some black plastic they'll be done this weekend)

But i'm considering rear skirts. The thing is, I can't screw cardboard or plastic on the outside of my car. The car is still new, with 25k on it, and still pretty. What i'm thinking is, Could i make nice looking, smooth wheel skirts out of fibreglass, and mount them in the rear wheel wells? That way I could paint them, (or have a body shop professionally paint them.... i know a guy), and they wouldn't look ghetto. I've never worked with fibreglass, and i have no idea what the costs would be. I'm not sure how you'd make a nice smooth mold either.

Thoughts?

[KJSatz]

Go for it. You never know until you try. As someone with a newer car, I agree with you...not out for an eyesore on this one. Good luck!

This post was kind of meaningless, but hopefully it was also kind of encouraging!

Edit: Now this is veering off topic! However I notice you are getting better MPG than I am in a car with lower EPA, so I want to learn from you . What do you do? I saw in your vehicle profile you have a scangauge; what in particular do you pay attention to? Thanks!

[ChrstphrR]

stevey_frac,

I've been thinking over rear skirts and partial fronts since last summer.

And, I think the best first attempt to mount a skirt would be the way that MetroMPG did in his Skirt Thread:

http://ecomodder.com/forum/showthrea...html#post37306

Second picture in, shows his attachment method, using screws and flattened copper piping to provide tabs to mount skirts on.

I don't own a Cobalt, so I can't say where the screws are that hold on your plastic inner fender. On my Jetta on the back wheels there are three mounting screws on the top along the outside edge. Likely it's the same sort of setup for your car too.

What I'd suggest is: Make copper pipe "Brackets" that allow you to use your inner fender screws to hold the copper pipe brackets.

A drilled hole in each end of the bracket will allow you to mount on the existing fender screws, and a screw or other means of attachment to your skirt.

If nothing else, these can be your first-generation / prototype brackets ... you could use aluminum or steel bar stock to make something sturdier, if you find you need to.

Paper/Card/Cardboard strips and a pen or marker might be useful to template out where your bends and holes on each bracket need to go.

The nice thing is, even if you need a different size/shape of bracket for each mounting point ... there's an identical one on the opposite wheel well, after you've figured those out.


You can only plan so much until you have to dive on in... get to 'er!

Oh, and take pictures, if you can! ... MetroMPG was grumbling about his poor pictures in the thread I pointed out. Yet more pictures will get more people to take the plunge after they see how easy it can be.

[cfg83]

stevey_frac -

I agree with ChrstphrR, MetroMPG has a really good DIY.

If you don't want to drill any holes, then you need to figure out how to "reuse" whatever existing holes you have. I found some (partial) pictures of Cobalt fender liners :

http://www.griptuning.com/ImgApp/install/0000000130.pdf
(Look on page 10)

From these pictures, it looks like there are a lot of fastening holes to work with, at least towards the bottom.

Can you remove your rear fender liner and take pictures, or count the number and location of fastening holes you have?

Even if you don't use the existing holes, you can make holes in the inner fender liner as needed. This is a *replaceable* piece of the car that doesn't serve an aesthetic purpose. You can always restore the car by covering the holes or getting another set of fender liners.

CarloSW2

[stevey_frac]

Originally Posted by KJSatz

Go for it. You never know until you try. As someone with a newer car, I agree with you...not out for an eyesore on this one. Good luck!

This post was kind of meaningless, but hopefully it was also kind of encouraging!

Edit: Now this is veering off topic! However I notice you are getting better MPG than I am in a car with lower EPA, so I want to learn from you . What do you do? I saw in your vehicle profile you have a scangauge; what in particular do you pay attention to? Thanks!

A lot of my mileage has to do with the fact that i drive a lot of highway. The rest of it is shifting low and some EOCing. Perhaps the occasional draft of a transport from 100'. My scanguage, i watch my instantaneous and average.

[stevey_frac]

Originally Posted by ChrstphrR

stevey_frac,

I've been thinking over rear skirts and partial fronts since last summer.

And, I think the best first attempt to mount a skirt would be the way that MetroMPG did in his Skirt Thread:

http://ecomodder.com/forum/showthrea...html#post37306

Second picture in, shows his attachment method, using screws and flattened copper piping to provide tabs to mount skirts on.

I don't own a Cobalt, so I can't say where the screws are that hold on your plastic inner fender. On my Jetta on the back wheels there are three mounting screws on the top along the outside edge. Likely it's the same sort of setup for your car too.

What I'd suggest is: Make copper pipe "Brackets" that allow you to use your inner fender screws to hold the copper pipe brackets.

A drilled hole in each end of the bracket will allow you to mount on the existing fender screws, and a screw or other means of attachment to your skirt.

If nothing else, these can be your first-generation / prototype brackets ... you could use aluminum or steel bar stock to make something sturdier, if you find you need to.

Paper/Card/Cardboard strips and a pen or marker might be useful to template out where your bends and holes on each bracket need to go.

The nice thing is, even if you need a different size/shape of bracket for each mounting point ... there's an identical one on the opposite wheel well, after you've figured those out.


You can only plan so much until you have to dive on in... get to 'er!

Oh, and take pictures, if you can! ... MetroMPG was grumbling about his poor pictures in the thread I pointed out. Yet more pictures will get more people to take the plunge after they see how easy it can be.

I'll take pictures. Give my wife's digital camera a workout.

I'm not worried about the mounting at all really. What i want is a smooth, professional looking cover. Something i don't have to be ashamed to bolt onto my car.

[stevey_frac]

Originally Posted by cfg83

stevey_frac -

I agree with ChrstphrR, MetroMPG has a really good DIY.

If you don't want to drill any holes, then you need to figure out how to "reuse" whatever existing holes you have. I found some (partial) pictures of Cobalt fender liners :

http://www.griptuning.com/ImgApp/install/0000000130.pdf
(Look on page 10)

From these pictures, it looks like there are a lot of fastening holes to work with, at least towards the bottom.

Can you remove your rear fender liner and take pictures, or count the number and location of fastening holes you have?

Even if you don't use the existing holes, you can make holes in the inner fender liner as needed. This is a *replaceable* piece of the car that doesn't serve an aesthetic purpose. You can always restore the car by covering the holes or getting another set of fender liners.

CarloSW2

I'm not worried about attaching the covers, or punching holes in the fender liner. There are actually a LOT of existing screws to stick it on. What I would like to do is make a little bubble that sits around the lip of the fender, and pops out about an inch. I can hinge it at the top, and use rubber feet, and use small bungee cords to hold it to the side. The hard part is making them...

[LeanBurninating]

Stevey, I really hope you decide to go through with these the fiberglass way. I think OEM quality skirts would be way cool. Like you just said, making them will be difficult. You will most definitely be going the extra mile but in the end the results could really be worth it. If you have the time and you get it done right, you might be able to make a few bucks selling additional ones off to other cobalt hypermilers.

I, too, have zilch experience with fiberglass but to speculate, you may want to jimmy rig some ghetto skirts first to help you make your mold. I would guess that either wood or a type of styrofoam may work best for a mold. Best of luck.

[sepp]

is the opening of the wheel well close to flat, or does it bend in 2 dimensions? if its close to flat you may better be using aluminium plates, it's cheaper and they are already flat! chances that you can make something of decent quality out of fiberglass from the first try are close to zero. but obviously once you mastered it somehow, then possibilities of making complex shapes become far greater.

[evolutionmovement]

I would also think aluminum would be the quickest and lightest solution. I guess I'll find out if I try it on my wagon whenever I finish restoring it.