Kardboard Kammback II

[trebuchet03]

I've done something unspeakable to my car!





I'm about to head on the highway for 2 hours....I really won't be able to do much in the way of testing unfortunately And likely, when my family sees it... there's probably going to be a few instances of yelling followed by it being removed.... But... itt'l be back.

Afterwards, It needs a polish to get rid of tape residue


I think I'm going to add two more panels on the bottom sides -- to finish off the rear tail.

Oh, and you can see the brakes and you can see out the back It fits tightly as I cut the second piece to slide in and lock on it

Comments?

[BeeUU]

That is some serious testing!!!!

Dont forget the vortex generators!!!

[omgwtfbyobbq]

Just tell them you've cut your coefficient of drag by 30-50 counts. They'll understand. Looks pretty aero btw.

[trebuchet03]

Originally Posted by omgwtfbyobbq

Just tell them you've cut your coefficient of drag by 30-50 counts. They'll understand. Looks pretty aero btw.

You should see it now

I've got a little more to do... I just can't stop But I'm doing a little bit on to the hood and I'm going to make a better diffuser (probably won't make much of a difference considering the undercarriage is exposed).

[Bill in Houston]

Good stuff.

Good luck with it.

[trebuchet03]

Bad news nobody...

I gotta go top off my tank to check.. because the needle didn't move much... but there's some serious problems... I got 18mpg according to the SG... 18! Mind you... I was going very fast due to an error -- I was told the my sister's graduation was later than it really was... doh! So my driving wasn't very efficient.

I hit the washer fluid... and my rear windscreen got wet... So obviously I'm getting a nasty swirl... Plus it is nowhere near rigid enough. Hell, a semi passed me and sucked off a panel (not pictured here). I'll fuel up later and see if the SG is off (doubt it though). Modifications to come.

Here's the good news... In the city.. I got 50mpg over a 20 mile drive.... So perhaps there's a velocity that magnifies the swirl. I also noticed it didn't flap around as much at city speeds.

I'm either going to reconfigure to take it all down for the trip home

[usedgeo]

Originally Posted by trebuchet03

I've done something unspeakable to my car!

Comments?

It looks like you have station wagon envy .

I suspect that cars like my Saturn withe a generous radius between the rear quarter panel and the trunk lid and a nice radius on the sides leading into the back window don't suffer as much drag as some suppose.

Then again if I got the kind of mileage Basjoos gets people would listen to my suspicions .

One of the draggiest cars I think I owned was a 1972 Javelin with a little spoiler just in front of the rear window and sharp corners at the sides of the rear window.

http://www.freewebs.com/dougrotu/Par...%20(Small).jpg

I googled this picture. This shows how to make lots of drag. I managed 24 mpg running the 304 on four cylinders.

usedgeo.

[cfg83]

trebuchet03 -

You're a better man than me! Keep up the good work!

CarloSW2

[repete86]

I also made some temporary aero mods before my latest trip, but it didn't make too much of a difference (maybe it did though since I've never driven with five people and film gear filling the car all the way). I also lost them in the rain yesterday, but I think that they held up okay before that. I had them in lower drag areas.

Didn't take any pics though.

[trebuchet03]

Well.... I think something is wrong with my SG.... It told me 18.1mpg - but when I refueled... I got 35.5 (see gaslog).

I'm back home now.. and need to fill up again... But the SG said 13.x mpg and it said I used 8.8gallons of fuel.... Well, my gas gauge isn't even at 3/4 and my fuel tank is a little less than 15 gal (I think). That, and I went MUCH slower on the way home (constant throttle the whole way). Oh -- and I modified it, I'll have pictures later

From my short time in city... I'm getting really low readings too when the kammback wouldn't be doing anything anyway.... Something goofy is going on, and I'm not quite sure what it is :/