Undertray air flow...

[The Toecutter]

This is why A-B-A testing is so important. If you can nullify the weather and engine temperature as variables, you have a better chance of figuring out which the fuel efficincy gains come from the aeromods.

[usedgeo]

Originally Posted by The Toecutter

This is why A-B-A testing is so important.

If and when I get the underpan removable I might do some testing then. I bought u-nuts and screws to replace the plastic rivets at the front. It will need to come off when the oil needs changed.

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Thanks for the details, Ernie.
Please keep the pictures and observations coming as this evolves.
Bryan
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I did extend back another 38 inches. This was the remnant from the front piece. I used 3 inch furring strips screwed to the sills of the frame so that the 48 inch wide piece was wide enough. It was sagging a bit in the middle so I used heavy wire to tie it up closer to the exhaust. I still have 1 inch air gap. I don't think the furringstrips would be a good idea in wetter climates.

I need to come up with a strip to join the two pieces also. I think aluminum strip and screws will do.

This did reduce air flow through the radiator. I was running about 216F in 60 degree air. My 15 mile commute is not long enough to show this problem. When you look at the picture of before you see that the swaybar brackets hold the pan down under the radiator. I think I need some pipe insulation to fill that gap and route the air through the radiator.

With less air flow through the engine compartment my intake temp ran up to 180-190. Even though this was real heated intake air as opposed to the fake heated air experiment the mileage was too good to report. I don't think it was true. I do have my best ever tank going and I am quite confident of breaking 50 mpg. I should revert to unheated intake air to get a baseline for the belly pan mod.

Sorry I did not take any pictures. I might get some later but I have a couple weeks of interference coming up. I probably should not refer to the 25th wedding anniversary as interference.

I have started on the rear wheel pants now. I should put a belly on the back but I have not given up on mounting a motor some where yet.

Ernie

[GasSavers_BluEyes]

Originally Posted by CommodAnt

Is there an ideal place to vent excess air??

My ideal place would be through the hood. Take a look at the Ford GT40's.
Not only is there usually a low pressure area just behind the front edge of the hood caused by the air curving around the shape of the car, but this also keeps air flowing over the car rather than under it. That is a 'cleaner' solution and also works to reduce front end lift.

Downside is that most cars have a pretty tight engine bay so doing any dedicated ducting is probably not practical and you've gotta have the guts to cut a hole in the first place!

[red91sit]

Originally Posted by BluEyes

My ideal place would be through the hood. Take a look at the Ford GT40's.
Not only is there usually a low pressure area just behind the front edge of the hood caused by the air curving around the shape of the car, but this also keeps air flowing over the car rather than under it. That is a 'cleaner' solution and also works to reduce front end lift.

Downside is that most cars have a pretty tight engine bay so doing any dedicated ducting is probably not practical and you've gotta have the guts to cut a hole in the first place!

Another idea (one I've been playign with) is to route the air to the wheel wells, I believe these are rather low pressure as long as you have good shaped wheel wells, I noticed on my fathers Elantra, there are some vents going into the wheel wells

[Bman83GL]

Thanks for the update, Ernie, and congratulations on your interference.

Both BluEyes and red91sit make good points. Through-the-hood is optimal for several reasons. But if you don't want to cut holes in your bonnet, ducting BEHIND the front wheels does indeed tap into a low pressure zone.

Bryan