Project Sexy Beast 93 Altima

[nmtmechengineer]

Introduction: I have been reading on this site for about 1 year now, so I finally thought I would start modding a car and posting.

Purpose: Get better gas mileage in the cheapest way possible.

Car: 1993 Nissan Altima GXE 2.4 4-cylinder automatic.

Mods:
-Full Grill Block upper and lower
-Front air dam, made with old bumper cut in half and bolted on upside down
-Wiper Cowl
-Passenger Side Mirror Delete, Drivers side folded back
-Side Skirts Bought from Lowes gutter venting they were $2.50 a piece.
-Taped Wheel Covers to close holes on Rear Wheels.
-Rear Deck Spoiler, Made with Coroplast and the Lowes gutter venting
-Fully Belly Pan on car with Diffuser of 8 degree built into the back and 2 guild vanes
-Boat tail Rear tires with cut up front bumper material
-3 Air Tab VG's above rear window centered
-Aluminum Taped Seperating Edge on Rear Bumper
-Sealed Gap on Door Handles, so it only requires 2 fingers to open
-AC Delete
-Beaded Seat Covers
-Driver Mod
-Tires running 45 psi.

Future:
Next mods contemplating are lengthing the deck spoiler to get the 12 degree angle off the back. Currently it is about 20 degrees off the back roof to the tip of the spoiler.
Re-install the Rear Wheel Skirts which had problems with the mounting brackets because I didn't want to tape the edges around the wheel well or screw in screws.
Maybe partial front wheel skirts
I was looking into the Partial Kamm back for a sedan also.
I need a tune up too.

Current State:
After all this I am currently getting about 30 to 38 MPG measured from watch the gauge hit E on two different half tanks.
Problems with it currently are a small oil leak forming, can't fill up the tank to full because if it gets too full a little bit of gas leaks some how on the coroplast belly pan.

Question:
Lately I have been thinking about adding extensions off the back end to the rear of the bumper edge to be legal.
I was hoping to see if anyone who has done this before has any input I have two different designs in mind.
1. Start where airflows from the side of the car to the back bumper then taper in using Corolast.
2. Come straight off the back edge off the car about 3 or 4 inches away from the sides.

Feel free to comment on my other information. I know the gas mileage approximation is not accurate and method is awful to say the least. I just need to figure out where the gas is coming out of when I top it off.

[nmtmechengineer]

Hmm I would attach a picture or two to help anyone get the idea of what I'm thinking about doing. But I don't know how to or if I have enough privileges yet. I took two pictures with my iPad and tried to post a reply then attach a picture.

[AeroModder]

You need at least 5 posts to attach images, and it looks like you have 6 right now, so go ahead!

[nmtmechengineer]

Attached are the pictures of the car.

[nmtmechengineer]

Funny thing about this car is everyone around here always tell me they have spotted my car. They didn't know it belonged to me.
They always say I saw that MPG on the it. Its funny most people don't even know I drive it despite the clear windows.
It used to have rear wheel skirts but the brackets kept touching the tire.

[MetroMPG]

Please: Your Garage: [ Add new vehicle ] - would be nice to have your fuel log here as an example of a well-modded Altima for other Altima owners.

Condolences on the automatic transmission, though! Sure cramps your potential.

Originally Posted by nmtmechengineer

Question:
Lately I have been thinking about adding extensions off the back end to the rear of the bumper edge to be legal.
I was hoping to see if anyone who has done this before has any input I have two different designs in mind.
1. Start where airflows from the side of the car to the back bumper then taper in using Corolast.
2. Come straight off the back edge off the car about 3 or 4 inches away from the sides

I don't think we've had many members doing this mod yet. Either approach should be better than stock, but an "organic" taper (option 1) will beat the "box cavity" approach. Airflow will re-attach on the straight-out box cavity extension provided it's properly designed, but you'll still be losing a small amount of energy to the vortex/turbulence trapped in the pocket between the point of separation and re-attachment.

Hope you get the fuel leak sorted out - it would drive me nuts to have to approximate my fuel consumption!

And welcome to the forum.

[nmtmechengineer]

Hi I been some what busy, cold weather is having negative effect on gas mileage. Although I have fixed gas leak from old fuel lines, and oil leak on crank pully. In addition I added the wheel skirts, re adjusted the rear diffuser angle to 5 degrees from 8 degrees. Then added some more length to the rear deck spoiler. I'm in the process of designing a rear kamm back that will extend to the rear spoiler. I want to use some clear plastic for part of the kamm back. I have plenty of aluminum and coroplast to make the kamm back. Im also considering converting the car to manual, I have done this two 3 other cars in the past. I will post a picture. I was thinking about posting some pictures for build of the kamm back for the sedan. I like the way 2000neon built his.

[nmtmechengineer]

Rear spoiler has been lengthened by 6 inches at 8 degree angle. I re-attached the side skirts and integrated them into the wheel skirts.

Planning rear Kamm back before I try to att rear cavity to car I might angle the cavity like a boat tail I need to figure out if I will violate the laws here in New Mexico and Colorado. I drive to Fort Lewis almost daily from New Mexico.

I would have more willingness to block my view on the Kamm back if I was not on probation and having something sticking off the car past the bumper.

[aerohead]

Originally Posted by nmtmechengineer

Rear spoiler has been lengthened by 6 inches at 8 degree angle. I re-attached the side skirts and integrated them into the wheel skirts.

Planning rear Kamm back before I try to att rear cavity to car I might angle the cavity like a boat tail I need to figure out if I will violate the laws here in New Mexico and Colorado. I drive to Fort Lewis almost daily from New Mexico.

I would have more willingness to block my view on the Kamm back if I was not on probation and having something sticking off the car past the bumper.

As I understand it,a 48" 'rigid' boat tail is allowed,and a 60" 'inflatable' structure is allowed under Department of Energy/D.O.T. rules when pertaining to energy efficiency.
In the 1980s the Federal Govt. was giving companies up to $400,000 or so through DARPA grants to develop and commercialize such things.
I've been driving across the USA with 'wacky' vehicles since 1974 and have never been cited by law enforcement.

[nmtmechengineer]

Tonight I finished the Kammback I ended up making it extend to the rear spoiler edge, Wired up a brake light for it and used my clear plastic from home depot 30x36, braced it down the middle with angle aluminum I was going to use to secure a subwoofer in my camaro.
After doing that I ended up making the rear cavity extending from the edge or the sides I used some clear plastic so the brake lights are visible from the sides. I need to modify the Kamm back so I can see out the sides because I noticed there is blind spot. Angle starts at 12 degrees then finishes off 14 degrees. Sides angle starts at about 5 degrees then tapers to 10 degrees at the end. I noticed the rain slowly moving down the glass tonight it looks neat to say the least. I still need to radius the rear cavity on the bottom sides it is square for the time being.
I compared the length of the car to my 2008 impala and the impala is still approximately 1.5 feet longer than the altima.