Old Cars and Aerodynamics~

[albyneau]

Looking towards the possibility of building a diesel powered car for a daily driver. I've got a 26HP Mitsubishi tractor motor lying around, and toying with the idea of coupling it up to a good 5-speed, and popping it into either an ultra-light body, an aerodynamic body~ or hopefully both! So far my list has the following chassis possibilities:

 

Datsun early Z

Datsun 1200 fastback

MG Midget

MGB

Triumph Spitfire

 

Parameters:

Must possess superior aero design, or

Ultra-light (the 1200's 1540#'s), or both,

Front engine/rear drive,

Pre- 1975, i.e. no smog. (i'm in CA), and

Of moderate/large production numbers (for parts accessibilty).

 

It'd get gutted to a spartan level, and shaved/frenched/smoothed to baby-butt status on the outside.....

 

Let the ideas begin~!

 

Peace~

Scott

[datzenmike]

Datsun 1000 or 1200 or maybe the Midget but they and the MGB and Triumphs have a heavy frame. Z car is also too heavy I think. Lower to the max to reduce frontal area to the wind. Shaving everything is too much bother for 0.00001% better mileage. You would get more from a light aluminum skin on the under side to reduce air turbulence. Weight determines mileage more than aerodynamics plus you are limited to 26 hp... doubtful it will pull in a 5 speed... maybe if diesel? .

[Lonestar]

Or you can find a light car and build a lightweight body kit like this.

 

 

[Skib]

an S30 was never designed with areo in mind.

 

stock valance creates lift at speed.

[DAT510]

for parts availability, MG Midget my neighbor has like 10 of them in his driveway and garage. seems like they arn't rare cars either cause i see them all the time.

[Guest 510kamikazifreak]

[Tristin]

What if you used some sort of StarQuest body?

[VintageRice]

I like it................do it.

[datzenmike]

26hp... I don't know.Even the Midget had 46

[albyneau]

D-Mike~ guess I should've phrased that different, it is indeed a diesel- 26.5hp @ 2000rpm, other specs as yet unknown. Didn't mention "bellypan" cuz I figure if you can spell aerodynamics, then you know the benefits of having one! An early Z is at the extreme upper end of weight~ but confident that if I used one I could trim the weight down 500#'s at least. Still heavy~ but not off my list...

 

Skib~ have to think upside down here; a controlled amount of lift reduces rolling resistance, another form of friction to be considered. Until it's up-n-running so I can do my wind tunnel testing I'm not so worried about keeping air out from underneath- but that the airflow down under is clean (belly pan, reshaped a-arms, etc.). Still we're hypothesizing on the heaviest (but coolest) car on the list thusfar...

 

DAT510~ definitely the smallest, lightest, and lowest frontal area on the list! But the box needs some aero-work for sure... Your neighbor need me to get any of them out of his way...?

 

510Freak~ LOVE old celicas! Got an '85 GTS in the driveway~ but guess what? With it's 22RE 4 cyl (and NOT counting it's fully loaded w/ sunroof, electric everything, etc) it weighs 300#'s MORE than the Z's~!

 

tristinGrind~ note to self- lookup StarQuest bodies....

 

Also added to the list is the Opel GT~ but availability (both car and parts) gives two strikes to this choice...

 

VintageRice~ In the immortal words of Bartles & Jaynes- thank you for your support!

 

[Ratty260z]

Early aircooled VW of your choice, very light they had about the same HP anyways. There is a guy with a yamaha R1 powered beetle who got the weight down to 1060lbs with him and a full tank of gas. You could have kennedy engineering make you an adaptor plate, so you could use the stock tranny which should be geared pretty good for a low HP motor since early beetles had about 30hp depending on the year. Not sure about aero but modifications could be made, plus you can get them pretty cheap. I'm actually in the process of building a subaru powered super beetle, weight goal about 1700lbs and pushing almost 200hp. Should be fun.

 

You could always try turboing it for some more power/economy.

 

Another idea is a early Honda or possibly a samuari. Lighter would be better in your case, I own 2 light vehicles with around 65hp and they are slow haha, not too bad really. Maybe a Sand rail esque frame built vehicle depending on your skills.

 

Also the lightest Z I've seen was a full out race 240z and it weighed 2000lbs, they do make a fiberglass replica shell in the UK that weighs 440lbs though..

[Skib]

Skib~ have to think upside down here; a controlled amount of lift reduces rolling resistance, another form of friction to be considered. Until it's up-n-running so I can do my wind tunnel testing I'm not so worried about keeping air out from underneath- but that the airflow down under is clean (belly pan, reshaped a-arms, etc.). Still we're hypothesizing on the heaviest (but coolest) car on the list thusfar...

 

Iv spent quite some time studying Z aero

 

some data from wind tunnel tests from stock body to one modded with airdams, various spoilers, sealing and reducing the grill area and other aero mods.

 

drag ranges from 342lbs. to 270lbs.

front lift ranges from 374lbs to -154lbs

rear lift ranges from 117lbs to -176lbs

 

lift as some pretty dramatic ranges while despite all the different mods the drag is hardly affected.

 

the Z aero can be greatly improved for racing or efficiency.

but it was never designed with any aero in mind, thus why I can be greatly improved haha.

altho the S130 was and it shows in the design.

[fourfiveten]

tube frame go cart. At least you'll feel the aero

[albyneau]

Early aircooled VW of your choice....

 

Dude~ you read my mind! While the tinkerer/designer/fabricator in me's dying to put this little diesel to work~ I have not excluded the possibility of building a nice Karmann Ghia with some econo-mods. I've an extensive background in Corvairs~ so the little pan-4's are beckoning to me in their own special way....

[DRIVEN]

Don't forget the Porsche 914. They probably compare to a Ghia in weight and aero specs but will probably cost LESS if you can find a roller project. The unused parts will also be more valuable and you can make more of your initial investment back. Here's a couple links with some figures that may be useful:

http://www.mayfco.com/tbls.htm

http://ecomodder.com/wiki/index.php/Vehicle_Coefficient_of_Drag_List

Or just copy this build:

http://community.ratsun.net/topic/7146-a-series-fuel-mileage-record-holder/

[EricJB]

I've always wanted to do horrible things to an MG midget. By that I mean 260hp, not 26hp. If you can afford a porsche 914, you might want to look at a Beck spider kit car. A mid engine tube chassis, fiberglass replica of the Porsche spider that James Dean was killed in.It uses alot of VW parts to satisfy that urge as well.

 

 

 

 

 

[DRIVEN]

Spider = $20-40K

 

914 roller = $500

http://portland.craigslist.org/clk/cto/2893977059.html

[Kisor]

Wasn't the eco challenge gas mileage thing won by a B-210 a couple times? Got like 77mpg.

 

He did a lot of Aero mods. Some were a little much for everyday but B-210's weigh in around 2000lbs fully dressed. And didn't have a ton of power to begin with.

 

I imagine 1500lbs isn't too crazy to get down to.

[DRIVEN]

Yup, I linked it a couple posts back. Really cool build thread.

Or just copy this build:

http://community.ratsun.net/topic/7146-a-series-fuel-mileage-record-holder/

[Kisor]

Yup, I linked it a couple posts back. Really cool build thread.

 

 

Oops, didn't click on the links you put up. I looked for it earlier and couldn't find it.

[DRIVEN]

Yeah, it was buried waaay back. Pretty amazing results out of 40 year old technology and some clever engineering.

[MikeRL411]

There was a kit car body copy of the wide rear fender 911 called the Panzer. Might still be available?

[wayno]

I would go with the bug, at least you would have a decent chance of maintaining a reasonable hiway speed, and with the lower conversion costs, it might be economicly viable.

Don't know about the RPMs though, 2000 doesn't seem like enough for the VW drivetrain.

[DAT510]

VW is a great idea

[Ratty260z]

at 65mph in my 73 super beetle it was at 3500rpm the ealier ones had higher ratio's I believe those have about 50hp at the motor stock. A bus tranny swapped in would work great. Plus there are so many parts still available because they were made till 2003 in mexico. Also gene berg makes a 5 speed kit for the stock 4 speeds.

 

A diesel Baja would be pretty cool :D