The Holes!

[freebeard]

Originally Posted by paconassa

Aerohead, care to explain that a bit more in detail?
With which cfd are you comfortable with?

I'm putting words in aeroheads mouth here, but it's probably the primitve rendering algorithms. Traditional rendering techniques hit the wall, so to speak. You can't render a sufficiently large volume at sufficiently fine resolution to produce a viable result before the heat-death of Universe.

Personally, I look forward to more advanced software based on OpenVDB. Instead of thinking outside the box, this makes the box fractal and extensible.

Edit: well that's inaccurate. Open VDB uses sparsely populated four-level binaries trees, not fractals; this means calculation is more focused more closely to the surface. And it uses bitmasking to have — in addition to pressure and velocity — for instance color (for smoke streamers) or viscosity (for raindrops and groundwater).

[eco_generator]

Dear compdrag:

You made the biggest modification you could possibly make after getting the holy bumper, the UltraGauge. You modified the largest variable possible! The instant feedback will help with your gas mileage... more than you can imagine. You think you are doing the same as before, but that is impossible. You can't observe something without changing it (metaphorical stretch of Heisenberg's Uncertainty Principle).

I would put some yarn tufts around the edges of the bumper holes and see if they wave into the holes or out of them at speed (or maybe in and out, in and out). Some sort of attached GoPro would be ideal to document it.

Bottom line, if you really like the bumper holes... keep them! It's your car. You're welcome to enjoy it. You will be getting better mileage with the UltraGauge and offsetting any aerodynamic problems from the bumper holes (if there are any measurable).

[compdrag]

Originally Posted by eco_generator

Dear compdrag:

You made the biggest modification you could possibly make after getting the holy bumper, the UltraGauge. You modified the largest variable possible! The instant feedback will help with your gas mileage... more than you can imagine. You think you are doing the same as before, but that is impossible. You can't observe something without changing it (metaphorical stretch of Heisenberg's Uncertainty Principle).

I would put some yarn tufts around the edges of the bumper holes and see if they wave into the holes or out of them at speed (or maybe in and out, in and out). Some sort of attached GoPro would be ideal to document it.

Bottom line, if you really like the bumper holes... keep them! It's your car. You're welcome to enjoy it. You will be getting better mileage with the UltraGauge and offsetting any aerodynamic problems from the bumper holes (if there are any measurable).

Sounds like a good idea I have a Contour and a GoPro. Seems like I just need to find my wifes stash of yarn now. I know the nut behind the wheel is the biggest nut to crack when doing all of this, but other additions have to help too. I'm just going to keep testing, and taking ideas you all through at me and run with it.

So Yarn test will be next.

[compdrag]

Well the weather sucks here right now. Pouring like no other. Hoping it clears up here very soon. I have yarn and my go pro ready to go just waiting of the rain to die down so the yarn is dry the whole time.

[compdrag]

well the weather suck like I said, but I tried anyways. The yarn got to wet just from the road spray coming off of the back. I was expecting the in and out like was mentioned I put some on the outside, and some on the inside. Hard to see because of the water getting on the lens. I can make out the inner ones good at 70 mph they are just there going out. I will be doing it again along with yarn using some ribbon when I get a day with no water hopefully here in the next few days.

[compdrag]

Alright finally the weather got good enough to do a test. Starts out like 40 mph down to the ramp. I accelerated up to 70 stayed there for a little dropped down to 60mph then stopped. So let the comments begin.

https://youtu.be/22v7sP7f-xw

[Ecky]

It's hard to tell, but from 1:27 it looks like some of the ribbons are blowing inwards. Did you put some inside the bumper or are those just the ends of the ones on the outside?

[compdrag]

I taped them to the inside edge of the hole so they would be able to go either direction. I do have some inside they were all the pink yarn. My hard case for my go pro is missing so I have to way to mount that right now. So my Contour is all I have and I only have a strap mount for it. Once I get a case for my go pro I can mount it better.

[Ecky]

It's clear that air is moving through the holes, and I get the impression that more often than not it's out, but sometimes it's in. My guess is you might have a smaller but more turbulent wake, and I'm not sure if that's better or worse but chances are good it'll disappear into background noise in your fuel economy.

This was my solution to bumper parachuting:

[compdrag]

I will be doing most of the underbody here very soon. When I get to the rear it is going to be a challenge. I'm going to try and get the air flow from the huge flows that come Honda made that go into the bumper to go out those holes.