Removable air dam options

[Kodak]

Sorry, I forgot to add one other question:

The 65+ mods list suggests that lower than the lowest component may be beneficial, depending on the vehicle. What factors determine the optimum air dam height?

As of now, only about 3" more would make the air dam equal with the differential - giving the air dam a ground clearance of ~7". How would I know if lower is better?

[larrybuck]

I'm only stating my opinion shooting from the hip... I think what you are implying is that if the lowest part of the airdam is equal to other equipment under the chassis, then you would have a cleaner; sort of natural clean bellypan like effect! Correct me if my guess is wrong.

In theory, I'd say to make it NASCAR style, almost scrape the ground! That way, hardly any air is there to effect mid under chassis turbulance!

But the reality is that most of us can't completely eliminate speed bumps, maybe curbs in front of parking places, HUMPY type driveway or parking lot entrances.

Granted, I like the looks of a low as possible airdam. If you were to incorporate an actual bellypan later on; I'm guessing that the smartest MR. SCIENCE guys on here; would prefer the flatest possible flow picture of air underneath, as opposed to a 45degree front bellypan start from a low dam, thusly over dirty-ing, the UNDER AIR! It could cause LIFT, but how much at what speeds?

If for arguement's sake, the person doing this won't usually go over 50mph., where would be the trade off factor for lower CD from a lower dam vs. the 45 degree angle picture mentioned above??

I feel like I've opened a large can of worms, here!!!

[Kodak]

Late reply - I've been doing a lot of thinking on this but haven't come to all that many new conclusions.

Originally Posted by larrybuck

I think what you are implying is that if the lowest part of the airdam is equal to other equipment under the chassis, then you would have a cleaner; sort of natural clean bellypan like effect! Correct me if my guess is wrong.

Spot on Larry. My understanding is that the most gains come from doing exactly that. However, there is also a point at which going too low increases the frontal area (and, as you mentioned scrapes on curbs etc.) and then drag can actually increase. I guess there's something to finding that optimum height. I hope lowest underbody component is a good starting point.

I'm starting to consider different options for materials.Thin sheet metal or corrugated plastic (coroplast) is likely, lawn edging seems too bendable, but I could be wrong. Any tips on materials? Ideally, I'd like to paint it flat black so it's nice and discreet.

When and if I get this off the ground () I'll post a few pics and add to the Wiki for future users.

[Bill in Houston]

this stuff is stiffer than edging
Valley View Industries - Diamond-Lok Brick/Paver Edging
comes in an L shape. can hopefully find at lowes or the home depot.

[mekanic]

one could make hinged in the center where it is straight. and then have some pins or just a few bolts at the corners.

[Hubert Farnsworth]

That was before I added more screws to hold it on, but its still a bit of a work in progress.

I used what looked like a piece of rubber skirting board I found at Home Depot, 48" long and pretty much fits directly across the center of the bumper cover (which in my case was already damaged so I didn't feel bad tapping the holes in it), Except when I go much faster than before if I stick to 65-70ish I'm seeing between 37-39.9 mpg now where as before it was struggling to hit 35 when one of the panels was loose for the forward undertray. (I did have to combine this with a tire pressure of 40 psig and increased vigilance, however it does appear to have improved my mileage by 1-5%)

[larrybuck]

To Kodak: I'm sure coroplast would work. I am more used to using about a 1/4 inch plastic sheet stock which would be heavier, but is quite strong.

This here is not about your app., but if any of you guys have seen the 2nd. gen. Camaro that Hot Rod Mag. ran at Bonneville; at first glance their MASSIVE airdam seems like so much mass, that it would slow the car instead of speed it up!
That's what leaves me would a little head scratching... in theory wouldn't something that so substantially help the top end speed work equally for mpg., One could say in theory, a 50mph tops Ecomodder app. needs less weight, and mass??? Where is the line for too much/not enough airdam???

Of course, each individual app. is different, but can anybody give me general principles in this??? Thanks!

[Kodak]

Sorry to bring this back from the graveyard, but I have a follow-up question about air dam shape.

My stock air dam has a little lip at the very bottom.

If I want to add a 3" flat air dam extension right below that, then the lip part will no longer be at the bottom - it'll be in the middle. Won't that mean that air will more easily surpass the new dam?

My options seem to be:

1. Create a small lip on the extension too; it's okay to have two.

2. Don't make a second lip, just make the extension flat.

3. (My least favorite) Cover the first lip and make a new lip on the extension, so that it is at the very bottom.


For clarity, here's the lip I am referring to - the indented area:



and my original idea is this flat extension:



My goal is measurable improvement, not perfection, but I'm concerned that changing the location of the lip relative to the bottom of the air dam may have negative consequences.

A bit long winded here. Happy to hear your 2 cents on the matter.

[euromodder]

Extend the lowest lip further down, then make your own horizontal splitter plate to keep the air from spilling underneath your extended air dam

[Kodak]

Thanks Euromodder.

So I don't have to do anything to the existing shape of the air dam? Just change the newly added extension to include a horizontal splitter?

Here's my paintshop idea of what it would be from the side. Is this correct?