Focus Wagon Mods

[IkoIko]

I posted once in the introductions. Since then I've done a bit to my 2001 Focus wagon. I added a front air dam, stuck on Airtabs, and a small grill block.
Not sure about the effect on mileage yet. I only have one and a half tanks since the air dam went on. Here's a picture of the front air dam before I put on the grill block. I attached it to the bumper cover using epoxy.
The air dam and grill block are made from plastic lawn edging. The grill block is held in place by the Ford badge. I put the grill block on today, we'll see how long it stays stuck.

The most questionable mod for mileage improvement (IMHO) are the AirTabs. They are easy to install though.

[MetroMPG]

That air dam looks great! Hopefully you see some gains from it.

I think your suspicion about the AirTabs is right: FYI, I did an A-B-A test with them on the top & sides of a minivan, and saw zero difference (however was able to detect change from a cardboard semi-kammback, and see the effect of removing the roof racks). I haven't posted the details yet.

[KJSatz]

Looks good! I think emulating the mini-kammback from "Blackfly" would be another good project.

[IkoIko]

I forgot, the first thing I did was to remove the roof rack cross rails.
I've smacked the air dam pretty hard a couple of times and it is still in place with just a few scuff marks.
Thanks for the info on the Airtabs. I think they might have to come off and put on a Kamm back. That seems like a much biggger project though.
I'm thinking a belly pan should be next but I'm having a hard time figuring out where to attach it. I'll keep looking for info on that.

[IkoIko]

I've had the grill block on for about a week. At the same time I routed a temperature gauge into the engine compartment. It's a $20 LCD attached to a ~10 foot lead. I've been driving my usual 15 mile commute and monitoring the undehood temps. Cruising at 65 mph the temp would hover around 130 F with outside temps around 60-70. Today I had to drive 40 miles on the freeway. After 35 miles I noticed that the underhood temp was around 140 F, at the same time the engine temp gauge started to move from its normal halfway position. I pulled off the freeway and checked the coolant level and it was fine. I cut the grill block on either side of the Ford emblem and got back on the freeway. Once I got up to speed the coolant temp went back to its normal halfway mark and the underhood temp went down to 80 F!
I did not expect that little bit of lawn edging to make such a difference!
I'm guessing that there's a bit of heat build up that I don't see in my 15 mile commute. Is there a connection between the grill block and the air dam that is reducing the amount of air available to remove the hot radiator air?

[MetroMPG]

I would guess the addition of an air dam would be more likely to improve the performance of your radiator by making a greater pressure differential between the grille (high) and the area under the engine compartment (low) where the cooling air exits.

[IkoIko]

That was my initial thought too. I didn't read too much into the higher underhood temps when I first saw them, I was thinking that it was due to lower air flow where the temp sensor is located. But when the coolant temps went up I figured I should be safe and not melt my engine.
If the difference wasn't so dramatic between grill block vs. no block I'd think there might be something else going on. But the efffect was so big and obvious it has to be the grill block.
Any other thoughts about this?