Old bed liner for belly pan

[JMPVW73]

Thats a very nice Hilux! I had a '78 but traded it for a Karmann Ghia a year ago. I miss that truck but that was the best Ghia I'd found in 10 years. You cant keep them all.

I've been thinking that on a solid axel truck you could wrap the axels with sheet metal to make an airfoil and have a smooth pan against the frame but I dont think a Bronco 2 sits up that high.

[ngrimm]

Yeah that's my ElectraHilux. I should be be finishing up the conversion instead of working on this Bronco

[euromodder]

Originally Posted by ngrimm

Not sure if I should try to angle the bottom of the dam toward the rear of the Bronco or leave it vertical.

Keep it vertical.
The purpose of an air dam is to reduce the amount of air going under the car - pushing the air to the sides or even over the top.

Angling the airdam to the rear will make it easier for the air to slip underneath it - exactly what you don't want.

[euromodder]

Originally Posted by ngrimm

1. Is the curved transition from the air dam to the belly pan a bad thing?

Ideally you'd want a clean separation between the air going underneath the air dam and the air being pushed aside by it - that's where splitter plates come in, forcing the air to go either way.

Without a splitter plate, some air is going to spill underneath the dam.
A more rounded transition should result in a smoother (but slightly bigger) airflow going underneath the air dam and onto the belly pan.

[lunarhighway]

that actually looks pretty good, most aerodynamic cars and suv's seem to have an undertrat that angles up to meet the front bumper in the middle, i think the rounded transition won't be a bad thing, and the ribs are nice too.

what you may want to do is add some extra dams in front of the tires, google some random suv pictures or even recent sedans ( a mercedes c class for example)
and you'll notice the center of the airdam is a little higher and seems more inviting to allow air undermeath in a smooth way, but the area in front of the tires and suspention looks more agressive and obstructive... you don't want air to flow into the tires it seems. it looks like the sides of the dam don't cover the full width of the tires.
you may want to try flaring them out somewhat if possible, or adding something to them to achieve the same effect, but than again, adding the dam will improve over stock and without a wind tunnel perfect aero will be impossible to achieve anyway

[ngrimm]

Great advice gentlemen. Would it help the separation if I install a flat piece of 1/8" thick aluminum fastened to the bottom. edge of the air dam that protrudes a couple inches in front of the transition? Also should I bend the corner of the dam to blend with the fender and perhaps use the front half of a fender flare to divert air around the tires? One other thing, I removed some 80's style aluminum running boards. Should I put them back on (I could paint them black) and try fill between them and the sides of the belly pan? Notice in the picture below the vertical flat pieces that that stick out past the fenders. Not sure if that is good or bad.

[euromodder]

Originally Posted by ngrimm

Great advice gentlemen. Would it help the separation if I install a flat piece of 1/8" thick aluminum fastened to the bottom edge of the air dam that protrudes a couple inches in front of the transition?

That would give a clean separation between the air that goes underneath and the air that's pushed aside.

The air dam should only be about as deep as the lowest component that catches a lot of air underneath the belly of the truck.
Making it lower will increase the total frontal area of your truck, and that creates more aerodynamic drag.

Also should I bend the corner of the dam to blend with the fender and perhaps use the front half of a fender flare to divert air around the tires?

Shielding the tyres from the air also helps cut down on aerodynamic drag, but make sure you don't increase the frontal area of the truck too much by doing so.

One other thing, I removed some 80's style aluminum running boards. Should I put them back on (I could paint them black) and try fill between them and the sides of the belly pan?

Basically, anything you do to smoothen the messy airflow underneath the truck should help.

Look for user BamZipPow's Toyota truck.
He's covered the entire side area between front and rear wheels.

Another modified truck to look out for, is aerohead's T100 truck.

[ngrimm]

So would it be better to raise the air dam a few inches and let the belly pan bend downward under the diff? Also I think I can flip the top front section of the bed liner and use it as a small air dam chin or whatever it is called.

[UFO]

Love that old Toyota HiLux. Air dam looks good too.

[ngrimm]

I cut the dam off two inches in height got it all fastened down with screws in the dam part and heavy plastic ties (rated at 175 lbs) for the belly pan part. Still need to add the chin. I used a sawsall and a small sabre saw to do all the cutting. A step bit worked really well for drilling the holes. So the pan bows down about 3 inches as it passes under the front diff and bows back up about the same distance once behind the diff. Should I have kept it at the same level after the diff?