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Old 10-04-2011, 12:07 AM   #1 (permalink)
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B13 '91 Nissan Sentra aero mods.

I like to compete in economy run events and have used a few different cars over the past few years. One I haven't tried yet was my '91 Sentra SE-R [2.0 liter - 5 speed]. It's been lightened considerably from it's original [approx] 2450 lbs. down to 2020 lbs.


I normally use it for rallycross competition, but because of it's weight reduction, I decided to see what I could get from it in the recent Tri-State Fuel Economy Run event. I had three 4'x8' sheets of black choroplast and some lexan recycled from another older project. The following are the mods I came up with from browsing these forums.


First up was recycling the choroplast belly pan from my Datsun B210. The '91 Sentra is longer and a bit wider than the B210 so it isn't quite a full belly pan. This is looking from the rear axle area towards the front of the car.


Looking behind the rear axle. To the left of the picture is the back bumper.


Starting to fabricate the side skirts and rear wheel fairings.


These are the rear wheel spats I came up with. I am wondering if I made them too big/wide?


Front end closed in. I don't have the grill block taped on yet in this pic. I used a digital water temp gauge to determine the size of the cooling opening you see. The engine runs between 200-210 deg. F. The cooling fan comes on at 213 deg. Any comments or feedback are welcome on the profile I came up with under the bumper.


I used a combination of choroplast and lexal pop riveted over light aluminum angle from the Home Depot. I mocked up the supports for the Kamm panel from cardboard.


Then I bent them from aluminum strap. I used 3M body moulding tape to attach them to the trunk lid.


Complete rear section. Now it was 2:00 am the morning of the event. Enough is never enough so I decided I needed to close in the front wheels as well. So I spent the next two hours fabbing up front wheel fairings. I wanted to connect the upper to the lower and build a full boat tail but ran out of time.


After 1 hour of sleep I an ready to go on Sunday morning in Williamstown, MA for the event.


The car performed very well, netting a result of 76.04 mpg over the 105 mile course.

I very much welcome any constructive criticisms as I did all of this from the seat of my pants with no angle measuring or tuft testing.

Thanks, Mike

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Old 10-04-2011, 12:23 AM   #2 (permalink)
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Um, I'm guessing the front wheels still steer, but how??
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Old 10-04-2011, 12:49 AM   #3 (permalink)
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Quote:
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Um, I'm guessing the front wheels still steer, but how??
I modeled them from how they were done on the Aerocivic [they tilt outwards if the tires push on them]. I used the pleats of the choroplast as hinges and employ two bungy cords per fairing [front and rear] to keep them closed. I also afforded myself some extra clearance by using narrower 155/80R13 tires on 5" wide wheels. I make a conscience effort to plan my moves to avoid sharp turns. This is not an every day car. I wouldn't bother with these for my daily driver. These are just to get that [hopefully] big number in competition.
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Old 10-04-2011, 01:04 AM   #4 (permalink)
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WOW great work, looks great did you ever finish the full boat tail? Pictures?
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Old 10-04-2011, 01:11 AM   #5 (permalink)
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Impressive work !
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Old 10-04-2011, 01:13 AM   #6 (permalink)
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Looks great to my eyes.
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Old 10-04-2011, 08:29 AM   #7 (permalink)
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Nice! Considering everything you did and 70+ mpg I doubt you left much loss on the table. I can visualize rear end eddies tucking under what overhang you have so I'm skeptical how much more a full boat tail could help. Cool beans!
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Old 10-04-2011, 09:31 AM   #8 (permalink)
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Love it !

I would definitely drive that.

Last edited by Cd; 10-04-2011 at 08:15 PM..
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Old 10-04-2011, 04:48 PM   #9 (permalink)
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Do you enter NASCAR or General Lee style? Clean & tidy and very reproducible for many.


Vaporware, is not so vaporware.

http://ecomodder.com/forum/attachmen...5&d=1296259422

http://ecomodder.com/forum/attachmen...6&d=1296259422
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Old 10-04-2011, 08:46 PM   #10 (permalink)
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Quote:
Originally Posted by Reloadwin View Post
WOW great work, looks great did you ever finish the full boat tail? Pictures?
Thanks everyone. No I haven't. I was hoping to hear some negative things about my Kamm tail design to encourage me to rush a boat tail together before the 16th when I make one final attempt this year for a new personal best mpg.


I know that the sharp crease on each of the [top to side] panels of the tail are not ideal, but is there anything fundamentally wrong with how the tail ends, or how abruptly each lower side panel ends near the rear bumper?

Mike

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