Aero Mods for Our Odyssey
 

Well, I'm not about to do anything really radical to the family van, but tonight I completed my first aero mod to our 2001 Honday Odyssey van.

Before:

http://i340.photobucket.com/albums/o...oofRack001.jpg

After:

http://i340.photobucket.com/albums/o...oofRack004.jpg

No more roof rack crossbars!. I think we used it maybe once as designed in six+ years, so it's just wasting gas 99.999% of the time. Probably not a lot of frontal area reduced, but I'm confident it will help at least a little, and it only took a few minutes to do. Not only does this reduce drag, but it also removes 10 pounds or so of unneeded weight.

We've only been getting about 16 mpg in this van with all of the really short trips it does, but maybe this will give us 0.5 to 1.0 mgp improvement? We hope we detect some difference!

I'm leaving the side rails. They don't have much frontal area, are fairly smooth, and would be a pain to reinstall I think if I do need to use the rack sometime.

Dunno that you can expect that much increase, but it's a start. :)

At first I thought - man, the top of that Honda looks like it has a garage door pattern in the metal! :)

Don't forget, the side rails increase "apparent" frontal area in a cross wind.

But, it's a start - there's no need for them to be up there with that little use. Nice work.

The entire upper grille can be blocked with no issues. The grille block on our 2002 has been on for 3 years with no heat issues, ever. It also helps increase the heat of the intake air by about 40 degrees iirc

I'm considering a full undertray for the next mod. Does anyone know if this has been done on an Ody? Any documented results?

Kammback Odyssey
 

I've been wanting to add a partial kammback, fastened to the liftgate in place of the black plastic trailing edge that comes stock. Make it of clear or tinted lexan or acrylic to not interfere with vision too much, and end it such that it sticks up no higher than the bottom of the liftgate does when raised (to not hit the overhead door, for example).

Re: raising intake air temp- what's the point of diminishing returns? Cooling intake temps increases volumetric efficiency, since cold air is denser, that's part of the theory behind water injection; it cools the intake charge and also adds steam expansion.

For fuel economy you want lower volumetric efficiency because otherwise the engine expends energy to limit volumetric efficiency. I personally don't think that raising intake temperature is the right way to do it because when you actually want power you're going to cause some problems, but people do see gains.

Ideally, you would use cooled EGR or something like that. The Prius has it for example, and I think trucks have it for emissions reduction.

(sorry this post has nothing to do with aero :P)

A very small step in the right direction. Any plans for a full belly pan? That would give you a couple MPG.

Edit... wtf? This thread is three years old.

haha someone was using the search

I see no problem resurrecting dusty old threads if there's new info to add.

It's aliiiiiiiiiiiiiiiive!

savings
 

If the cross pieces were 1/2-inch thick,I estimate that at a constant 60 mph,removing them would save approx. 0.007 gallons each hour.

Completed an upper grille block this weekend. I removed the grille and traced a newspaper template from the grille trim ring, then cut it out of 0.020 aluminum sheet with mounting tabs that extend past the mounting screw holes.
https://www.dropbox.com/s/dglt6im5juazkhi/IMG_3181.JPG
And a quick comparison to a twin..
https://www.dropbox.com/s/jjgi1fmp1b...%20Comparo.JPG

jray: that block looks good.

Next step - remove that deflector from the hood!

Yeah- I take long highway trips so rarely that I was thinking to leave it on for better comparison to the baseline, but what the heck, time to shave that moustache!

That grill block looks really nice. It kind of reminds me of the newer Acuras.

Okay, here's a report on the Odyssey grille block (and bug deflector delete). The van warms up quickly, but water temp locks in solid at 181 F around town and in steady highway driving. Over some 2600 miles of highway driving from Washington to Colorado and back for Christmas vacation, the highest temp I ever saw momentarily was 189. Interestingly, it's not a long hill climb; but the downhill coast afterwards with an idling engine when the temp needle climbs, I assume due to slower water pump speeds.
There were too many variables and poor previous data collection to put a good number on the improvement (I'm also driving faster since confirming that the Ody's speedo reads 4 mph slow at highway speeds (but not the ODO!). However, over this trip during 70-75 mph daytime driving, the van got 21-23 mpg, and the best tank was 25.8 mpg at 65 mph at night (with a tank of 85 octane Idaho ethanol winter blend). This was over some steep highways; we saw 6% for over 6 miles on two occasions, with many other dramatic climbs not posted.

According to Aerohead, if you averaged 60 MPH, you saved 0.6067 gallons! :D

The only modification that I have done is remove the the crossbars, which were actually airfoil-shaped, but with an AWD automatic, it would be more difficult to see significant improvements.