Sedan boattail

[Gone2]

Obviously I own a Sentra. I have been thinking about doing a boattail on the trunk, but am curious how much of an improvement that would make on a small sedan.

[Frank Lee]

There's a Tempo on here with a Kammback.

[Sven7]

How big of a boattail? If you do it correctly it'll have to come off the top edge of the rear window unless you already have a kammback to build off of.

[Gone2]

I had never thought of trying a kammback on the car. I was debating on extending the back of the car about a foot and a half and narrowing the sides of the car. I messed up the deck lid while trying to reweld the top, and forgot to cover the back glass, so there is a lot to fix. The rear quarterpanel was dented when I bought the car and the back bumper is shot. Thus the time to try something custom. On to road legalities, is there anything illegal about testing something like this while blocking the back window? Also, how would a partial kammback and a boat tail work out? Might be time to do some testing

[California98Civic]

Originally Posted by Sentraguy

On to road legalities, is there anything illegal about testing something like this while blocking the back window?

Maybe. Do the online research. Here are two sites I quickly found:

North Carolina Traffic Laws - FindLaw
North Carolina General Statutes Chapter 20 Motor Vehicles - Legal Research

But take Frank Lee's advice and check out the Tempo Kammback thread first:

http://ecomodder.com/forum/showthrea...tml#post276457

It's informative. He did the testing you are considering, IIRC.... seriously, don't miss it.

I'll be following you with interest... every now and then I get the Kammback daydream bug again... but I still have too many half completed mods needing cosmetic work before I try another.

[aerohead]

Originally Posted by Sentraguy

I had never thought of trying a kammback on the car. I was debating on extending the back of the car about a foot and a half and narrowing the sides of the car. I messed up the deck lid while trying to reweld the top, and forgot to cover the back glass, so there is a lot to fix. The rear quarterpanel was dented when I bought the car and the back bumper is shot. Thus the time to try something custom. On to road legalities, is there anything illegal about testing something like this while blocking the back window? Also, how would a partial kammback and a boat tail work out? Might be time to do some testing

Hucho and his team streamlined the Jetta notchback by boat-tailing from the rear wheel centerline,back to the trailing edge,losing 125mm from each side.Cd dropped from around o.425,to 0.375.About 12% drag reduction ( 6% mpg @ 55 mph).
If you did a corresponding roof extension,you'd see greater reduction.
The Sentra should already have some side body camber.You could just pick up from where Nissan left off,gently curving in as you move aft.
If you can find a Mercedes Benz 190 from the 1980s,it would serve as a wind tunnel tested example of a proper notchback boat tail,as is mentioned by Hucho.I saw one yesterday here in Denton.

[California98Civic]

Originally Posted by aerohead

The Sentra should already have some side body camber.You could just pick up from where Nissan left off,gently curving in as you move aft.
If you can find a Mercedes Benz 190 from the 1980s,it would serve as a wind tunnel tested example of a proper notchback boat tail,as is mentioned by Hucho.I saw one yesterday here in Denton.

Like this?

[Gone2]

Yeah, the Sentra boattail has been eating at me for a while. I am wanting to fix the car up, but there is so much wrong with the body. I'm gonna look at making a semi temporary one from cloroplast and thin plexi, so I can tweak it until I am happy. I am thinking about just completely redoing the back end from scratch. I will have to see what I can dream up. Now to find the time and money in the same spot at the same time. Would I do better trying a partial kammback or just go ahead and test the full? I am leaning toward the full.

[Gone2]

Okay, just reviewed the Tempo Kammback writeup, was there ever a follow up to thishttp://ecomodder.com/forum/showthread.php/ford-tempo-kammback-19904-3.html Definately going with the bumper removal and redesign. I have been playing with designs all day on napkins, I am thinking about tapering the kammback a good bit and slightly tapering the car sides, about eight inches or so. The bumper will come off and it will gently taper down to the back axle. The underside of the Sentra is a pan already, so I don't know if it will make a huge difference to put the full "pan" on. I will do a partial on the front and back. Smoothing the rear bumper up to the end of the car should help seperation as well right?

[Gone2]

I am waiting for time to do the kammback, but I have done the wheel skirts I have been planning for some time (motivated by $3.61 per gallon gas). Anyway, I have been playing around with the photo editor, and let me know what ya'll think of this.