A few more small aero Metro tweaks; still improving

[MetroMPG]

So, the permanent Kammback is now mounted on the car and I did a few other minor tweaks.

1) Taped the hood/bumper gap. It's actually a fairly significant opening on the Metro, as you can see in this pic:



That gap is maybe 24 square inches. Running at around 50 mph on level roads, my coolant temp was sitting at 198-202 F with that gap taped up, which is a couple degrees higher than with it open. This car's fan kicks on automatically at 205 or 206 F, and off again at 195.

2) Deleted the exterior antenna from the A pillar. Just like Mullet did to his car. Taped over the opening for now.

3) Removed windshield wipers (beautiful day, not a cloud in the sky)

I'm seeing some pretty nice numbers at speeds I haven't seen before. Just did a 60 mile round trip on secondary roads 38 mph avg/59 mph max, driving with load on the open road where traffic permitted (pulling over, or speeding up where it didn't). EOC and P&G at either end where appropriate and saw 80 mpg (US) even for the round trip.

On one 7.7 mile stretch of mostly level road, in a flow of traffic (NOT drafting) with an 8 kt following wind, I saw 75.8 mpg averaging 52 mph/59 mph max.

I'm not saying these three mods are particularly significant or made a noticeable difference, but those are numbers I'll happily take!

[MazdaMatt]

so... the kamback... definate major improvement? definate slight improvement? interesting waste of time?

[groar]

Good work as usual

So little changes but effective on mpg !

Do you think they are effective because your car is already well modded, or can they be as effective on un-modded cars ?

I want to be this week-end that I'm working on my cardboard rear wheel skirts

Denis.

[MetroMPG]

The cardboard Kammback mockup/prototype was good for 2.3% better MPG @ 55 mph. The permanent one is both longer (ie smaller wake cross section) & better designed, so it's got to be better than that, but I don't know exactly how much higher.

[MetroMPG]

groar: I'm not sure. All I can say is all the small things add up, even if they're individually worth only a few percent or even fractions of a percent. Eventually I'll do coastdown testing to calculate the car's "new" Cd, but I want to do a few more things before that.

[MetroMPG]

To keep these numbers in perspective, I also specifically chose a route today that mostly shielded me from the front quarter head wind on the first leg, and exposed the car to the tailwind on the return leg. That contributed a lot.

Also, getting in that flow of traffic for about 10-12 miles helped even more on the return trip: "corridor effect" plus tail wind plus aero mods =

It's all about aero ... and keeping an eye on the instant MPG while driving with load.

[MetroMPG]

Forgot to mention: 3) Removed windshield wipers (beautiful day, not a cloud in the sky) ... added.

[SVOboy]

Darin's amazing!

[MetroMPG]

I'm just trying to keep up to your lazy @$$ lean burn CRX.

[Johnny Mullet]

I always thought that totally blocking off the bumper openings and leaving that slot open under the hood would be the ideal way to mod the front of the Metro. The antenna mod worked great for me and I happened to find the factory block plate in the glovebox along with the radio block plate in there. I assume my 1998 Base was radio delete, but the previous owner had an aftermarket radio and stock antenna installed until I bought it and he kept his radio.

I thought about making a cowl that would deflect some air from the wipers since they stick out in the wind like they do, but I would not remove the wipers myself because now and then the wife has to drive it and I will not want it to rain on her with the wipers in the back.