light weight car? suggestions (for removing weight from 81 VW Rabbit diesel)

[81rabbitdiesel]

Hi Guys,

I am thinking about possibly cutting some of my car away to lose some weight. Its a 81, 4 door rabbit diesel with hardly any rust anywhere its the one in my pic. I have 2 aluminum small truck camper tops that i can cut up to use to replace a lot of the cars heavy metal.

I was thinking about getting rid of the back door glass and the rear hatch and probably about 2/3rds of the roof and using one of the camper tops to close it all in . i am guessing this would be around a 200 or so pound weight loss. I thought of using part of the other camper top to make a front air dam for the car and a underbelly. It gets really hot down here in east texas so im a bit worried about doing to much of a grill block.

I am wanting to bust 70 mpgs with this car. heck 100 would be better but i dont think in this hill country thats gonna be to easy. One other option for weight reduction would be make it like a mini truck and just cut the back end off from the door glass up and use the camper shell to close in the back of the cap since it has the right small rear window set up already built in. I even thought about drilling holes in some of the metal to lighten it up.

I dont think i can get many more mpgs from the car with my driving habbits...... heck i would make most gramdma /grandpa drivers look like speed demons LOL.

any thoughts or suggestions?

Thanks for reading, Don

[Sven7]

As the owner of an '81 convertible I ask you to please not kill that beautiful Westy! Make reversible mods wherever possible.

If the interior is already stripped (and I hope you either kept it or sold it to an enthusiast) you could get lexan windows made and pick up some lightweight wheels. You can lose the bumpers and save some real weight, take out any A/C system it had (the compressors are heavy) and remove the spare tire.

It sounds like you do a bit of highway driving, in which case doing some aeromods would really help, possibly even more than weight reduction. GTI valences are supposed to be the most aerodynamic of the mk1 air dams, so try to get one of those from a junkyard. If you've already built a smooth belly pan I'd start on a Kammback or boat tail built off of the hatch. If you can't attach one without drilling consider building it off of a strap-on bicycle rack.

If you're looking for other ways to save weight search VWVortex for Mk1 racecar build threads. There are probably several to peruse.

Don't cut!

[DIMS]

Weight reduction to the max & documented

Lane's SCA - Project 92 SC - Weight Reduction (1)

Tom Stickland's MK2 Vauxhall Astra Pages (Opel Kadett)

[Stan]

I read a technical paper recently where the researchers improved the FE of a late-model TDi just 2% by removing about 250 lbs from the car. In contrast, reprogramming the chip yielded 4%.

OTOH, one CAN get 70 mpg from an old Mk1 dwiesel radjit...

Start by reading this Ecomodder thread and the linked article about the "Rabbit Sipster". Forget transplanting a TDi into it...just apply the aero mods he does and I bet 70 mpg is not out of the question. Heck, I used to get 50+ mpg from my first-gen Rabbit and Pickup both just by using a light foot.

[drmiller100]

you can move 500 pounds or so fairly easily, but then it gets expensive.

spare tire, glass to lexan, remove window regulators, bumpers, bumper supports, back seats, spare retracting seat belts, AC, etc. are all pretty easy.

or, start with clean slate, build a trike from scratch, and 1000 pounds finished is realistic with your power plant.

[Stan]

Tru dat, Dr Miller! The article I read did all those things, plus made carbon fiber hood and rear hatch, sun roof, etc. Big bucks for negligible gains. In the Rabbit Sipster article he gained about 10-12 mpg from the engine swap (from low 40's to ~55 IIRC), but got another almost 30 mpg from very crude aero mods (floor pan and front treatments, mainly). By the end they recorded ~84 mpg.

[Frank Lee]

I wouldn't hack up a nice one. There are plenty of rust buckets to choose from for hacking up.

[nimblemotors]

Originally Posted by Frank Lee

I wouldn't hack up a nice one. There are plenty of rust buckets to choose from for hacking up.

DO NOT start with a rust bucket of any car to modify. Rusty cars are dangerous and should just be crushed. The effort to modify a car deserves a good starting point. And geez, how many precious highly valuable 4-door Rabbits must we save??

I say go to town on weight reduction, if you have hills, it makes a big difference! But don't sacrifice aerodynamics in the process. A camper top sounds worse than the stock rear.

[ECONORAM]

Originally Posted by Stan

I read a technical paper recently where the researchers improved the FE of a late-model TDi just 2% by removing about 250 lbs from the car. In contrast, reprogramming the chip yielded 4%.

OTOH, one CAN get 70 mpg from an old Mk1 dwiesel radjit...

Start by reading this Ecomodder thread and the linked article about the "Rabbit Sipster". Forget transplanting a TDi into it...just apply the aero mods he does and I bet 70 mpg is not out of the question. Heck, I used to get 50+ mpg from my first-gen Rabbit and Pickup both just by using a light foot.

Interesting about the weight vs chip tweaks.

I also used to have an 81 diesel Rabbit, and saw high 40s constantly. Didn't know squat about eco-modding.
Take a look at three-wheeler's Honda or the aerocivic. A good boattail should help you out.
I also suggest you replace the soft rubber front motor mount with the harder rubber from VW Sport or better yet polyurethane. I ran a poly mount for some time; doesn't really change the vibes and it keeps the engine from rocking.

[Frank Lee]

Originally Posted by nimblemotors

DO NOT start with a rust bucket of any car to modify. Rusty cars are dangerous and should just be crushed. The effort to modify a car deserves a good starting point. And geez, how many precious highly valuable 4-door Rabbits must we save??

I say go to town on weight reduction, if you have hills, it makes a big difference! But don't sacrifice aerodynamics in the process. A camper top sounds worse than the stock rear.

Sheeit, here in the rust belt most everything over 10 years old has rust. They aren't dangerous- you just have to figure out how you're gonna attach the new metal.

Rabbits are like Vegas around here- haven't seen one on the roads in decades. I sure as hell wouldn't hack up a nice one, especially if the hack is likely to gain me 1 mpg... or less.