Project: The AeroFocus

[HydroJim]

I decided to put off the basjoos style front end because in Ohio I'm required to have a front license plate and the focus is already pretty rounded in the front. I did block off the upper grille block because it does absolutely nothing for cooling and should help my aero. I might pick up a piece of clear acrylic to put over the upper grille because the turn signals are mounted inside the grille and I couldn't block the whole thing off with coroplast

[suspectnumber961]

I did that when I started blocking the rad some and adding a front pan. Works real well. RadioShack.

Originally Posted by Sven7

One thing I've been planning is an LED to turn on when the radiator fan does. Maybe this would help you figure out how much is too much.

[Tango Charlie]

An LED fan indicator is a good idea. You can see how I put one in my car in my Vibe build thread on page 7. The following pages discuss my search for the minimum lower grille opening with some helpful suggestions from others. Someone mentioned 4 square inches for every 25 HP.

[Xist]

I need to stay up late reading these threads!

How difficult would it be to make a grill block open when the fan turns on?

Just... would you put it on a timer? How would it know when to close? A thermostat?

Great work so far!

[suspectnumber961]

All I can say is: be VERY CAREFUL when modifying your grill intakes/installing a front pan. You need a SG or UG to monitor coolant temps real-time AND the LED indicator to make sure your fan is working...but not all the time.

I was messing with a 300ZX and just about overheated it.

With my Focus the fan turns on at 233F...off at 222F...by the book. This only happens occasionally in town.

The addition of the partial grill block/front pan resulted in the engine reaching operating temps much faster and running at a higher temp generally. Before I thought I might have to replace the thermostat.

[HydroJim]

After taking about a week off to deal with the shock of going back to school, I've found some time to get some work done.

I added an upper grille block which I don't have any pictures of. I should have probably recorded before and after warm-up times, but based on all the people who have already done this mod, it can't be hurting anything.

I got rid of the steel flashing that allowed to boat tail to smoothly seal against the car. Although effective, I felt that it didn't look very good and it added frontal area which defeats the purpose of decreasing drag. The new setup is much better looking and should be better aerodynamically

here is what it looks like now:


For tuft testing, I hope I get cheap camera to rig like Metro MPG did but having someone follow me with a camera is free.

Now that I've concluded the tail is working good, I'm planning on getting the rear wheel skirts and rear wheel boat tailing done this weekend.

[MetroMPG]

Hope you'll post the tuft test video results. Remember: you don't have to go fast to tuft test. The air behaves the same at 25 mph as it does at 65.

[HydroJim]

Originally Posted by MetroMPG

Hope you'll post the tuft test video results. Remember: you don't have to go fast to tuft test. The air behaves the same at 25 mph as it does at 65.

Not that I'm doubting your expertise, but it would make more sense to me that at 65 mph, the angle required for attached flow would be a much lower angle than at 25 mph because at 25 mph, the air has more time to move down and in. As many of you have said before, aero doesn't not always follow logic and I'm just wondering if you can explain why it acts the same at 25 as 65. Just trying to learn!

[NeilBlanchard]

The flow template is the same up to ~250mph. I found this counterintuitive as well, but there is a localized high pressure zone that is generated by the movement of the vehicle, so both this localized pressure and atmospheric pressure "push" the air back into place.

[HydroJim]

That's pretty good to know! Any idea what happens after 250 mph? I'm gussing that's when laminar flow kicks in