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Tesla 02-07-2013 06:17 AM

Front bumper / airdam / undertray intake on 4x4
Looking to finalise my front end, up to about version 3 by now.
I've had various airdam types, but have decided to get more rounding in the front.
As with many 4x4's I have a bullbar (push bar) on the front like the first pic below, but I have upper grille blocked and have airdam across the bottom of the bar and infront of tyres to just below axle height.

This version is more undertray across the centre and curving to airdam infront of the tyres, radiator & combustion air intake currently is where the winch opening is, just below licence plate, but after more reading about front ends, undertrays, ground clearance & wheel air deflectors I am planing another version.

Basically I want to round the entire front down to the winch opening level, then for the air intake I would use a mesh grate as the undertray, roughly positioned like the bash plates in the two photo's attached, but angle would not be quite as steep.

The rounding at the front would deflect air around and over, any air passing under would firstly be drawn through to the intake and radiator through the first half of undertray (mesh) as there will still be pressure there as the 2nd half undertray (solid) will be angling down towards the axle. This should almost create the effect of having a 4" lower airdam.
So looking at turning it into a bottom breather.

So just looking for any input.

Saskwatchian 02-07-2013 08:58 AM

If this is version 3 do you have any pics of your own vehicle with your previous and current configurations? And maybe some drawings of what you are thinking. I have no idea how you are going to round the front, adding material? cutting off the tube work?

I am also having trouble envisioning what you are planning for the bottom as well. Are you going to try to keep your approach angle? I can't see how that would be possible with a dam.

What are you using the Patrol for? Weekend trips? Long range touring? The daily commute? Does it need to stay as capable as possible as an off-roader or not?

One thing I would try if I had a proper 4x4 with bullbar is to hang some mudflaps on the front of the bullbar like a semi/road train to deflect the air around your front tires without sacrificing offroad ability. The dirty air off the barwork actually might not be a bad thing with the not-very-streemlined body coming after it. I have heard a couple anecdotes of people adding bullbar expecting a drop in milage but instead getting a gain.

Tesla 02-07-2013 04:00 PM

Yeah, went to bed and thought about what I wrote and how twisted it was,
Most of my travel is road touring, some off road, but not hard core.
I expect to lose a bit of the approach angle, but the goal is to present a rounded and upward angled face to oncoming air, this will effectively slice the airflow at the lower level of bullbar, then do the combination mesh/undertray for air intake and to deflect excess air under front axle and I want to look at some specific detailing for fairing infront of the wheels.

The first version was basically just a lower air dam that was straight across, but I felt it was throwing too much air out the sides and increasing apparant frontal area.
I think with vehicles like mine, 12+" ground clearance to axle, there is more allowance to let air go under, particularly if you do some smoothing on the underside.

I will get some better pic's to try to explain idea.

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