I completed the main portion of the belly pan today. Lot's of time and energy went into it, but the result is quite nice. The header collector hangs down lower than anything else under the car. I knew this going in, so I had to decide whether to work around it and allow the exhaust system to be exposed, or lower the entire belly pan and close it in completely. I measured the height of the bottom of the chin spoiler to the floor and it was the same as the height of the header. So I decided to enclose the exhaust system in and have a perfectly flat belly pan front to back.



I used aluminum tubing to space the pan to clear the header and pipe. I did not drill any holes in the car at all. I pressed plastic anchor bushings into pre-existing holes in the bottom of the frame rails. I used thin aluminum sheets [cut from food catering trays] as a heat sheild under the exhaust system. Not pretty but it should work fine and you won't be able to see it when this the side skirts are installed.




Tomorrow I will fabricate the side skirts to close it all up. The rear of the pan slipped nicely under the rear valance panel. Again, there were no holes drilled in the car at all for this project. That's why it took a bit more time to do. I had to get creative to preserve the integrity of the car. I will try to get some finished pics tomorrow, but a black pan will be very hard to photograph. The bottom of the car is completely smooth and flat.

Mike

I did some more work today and finished the side panels and kick ups behind the wheels.




After this pic was taken I continued to work on the car. I realized that there is a need for providing an exit for the radiator and exhaust heat. Remember, by closing off the bottom of the car, I've also closed off the normal escape point of the underhood cooling air [between the frame rails along both sides of the engine]. This cooling air from the radiator must be able to flow through or it will back up and the engine will overheat], not to mention the adding unwanted aero drag. So I cut some large slots into the rear of the belly pan to [hopefully] keep things in balance. I'm sure the floor temp of the car will be raised as well. Between that, and having the windows up tight [for lower aero drag] it will be a good thing I am bringing a cooler with cold towels in it to wear as my "air conditioning".

wow u r getting really serious now

I really love what you are doing, this model is prob the nicest looking 120y datsun and rarest for their model.

I have to say great job on the whole thing. The only thing I would suggest is raising the bonnet rear so the radiator air escapes onto the windscreen instead of the belly pan which is smooth and wonderful. The hot air over the top will create a minute downforce effect of warm air escaping up and over the car, its small I know but it all adds up. The other thing to do to your exhaust is cover it completely with heat tape. The thermal insulation will create better gas flow which is a proven method for exhaust efficiency and expulsion.
Maybe the side indicators or reflectors can be replaced with stick on thin ones and the indicator modded (get an old one and file down its height or use tapered bolts the outside and glue the nuts on to the back of the indicator housing flanges. Finish off with flat amber cut-out section from a toyota or other junkyard indicator sections. All minimal gains (except exhaust which is a worthwhile expense and saves on heat building up) but all adds to better results.

You might also look into what the eco-honda did with the wheel arch covers where they just hang like curtains and the turning tires at the front just move them out as out needed.

Overall a great project and a great addition to our website.

Thanks for the compliments D. It's funny you mentioned the side marker lights because I was looking at them yesterday and noticing how much they stick out also. But I'm out of time now for preparing for this event, as I have to go to a wake this afternoon thru Saturday. So I am just finalising the clear plexiglass headlight cover and partial grill blocks this afternoon. I have plans for a Kamm tail too, but I won't get to that for this Sunday.

Hey, we've got to leave something on the table for future events right?

Here's some more stuff for your table...
http://www.airtab.com/en/
I read about these air tabs in Sport Compact Car.

Also, the side markers could possibly be mounted from inside the panel. Basically, instead of lens,housing,fender,clip its fender,lens,housing,clip. The screw head would be the only thing sticking out. I think I have an example pic.

For those who follow this thread I have some great news for you. Last October 5th, 2008 I set what I consider to be the highest mpg ever recorded for an A -series Datsun engine at the A.M.E.C. Economy Run II event. That number was 61.5 mpg [US gallons].

With all of the further modifications you've read about in this thread, I competed in this past Sunday's A.M.E.C. Economy Run III event. I completed the 104 mile course through the hilly southern Adirondack mountains and the post event refill showed that my fuel consumption was 1.35 US gallons of gasoline.

This equates to a new record of 77.04 mpg . [We hit our goal of 70 and then some David! ]




Here are all of the event results:

Note: I could have easily won the Historic class ['79 and older] but I chose to run with the heavy hitters in the Gas class and go head to head with much newer and highly modified gas cars. This was a little silly to try as the Hondas have factory fuel injection, electronic lean burn systems, vte-c, etc. But as far as carbureted cars go, I had them covered.

Gas class

1. Chang Ho Kim - 1989 Honda CRX HF - Maynard, MA 118.1 mpg
2. Darin Cosgrove - 1998 Pontiac Firefly - Ontario, Canada 106.12 mpg
3. Ben Jones - 1991 Honda CRX - Hanover, NH 82.54 mpg
4. Mike Kamm - 1977 Datsun B210 - Averill Park, NY 77.04 mpg
5. Will Meredith - 1998 Honda Civic EX - Binghamton NY 64.62 mpg
6. Richard Vedder - 2000 Ford ZX2 S/R - Johnstown, NY 59.09 mpg
7. Eric Hoefer - 2008 Honda Fit - Guilderland, NY 47.27 mpg
8. Robert Smalls - 1996 AWD Subaru Legacy - Buffalo, NY 46.64 mpg

Diesels and Hybrids

1. Martin Deschenes - 2000 VW Jetta TDI - Quebec City, QC 90.43 mpg
2. Matt Herring - 2009 Toyota Prius - Boston, MA 75.91 mpg
3. Hobbit - 2004 Toyota Prius - Boston, MA 74.28 mpg
4. Dan Mandle - 2004 Golf TDI [Vegetable Oil] - Potsdam, NY 63.41 mpg
5. Dave Burnham - 1991 Jetta Diesel - Delanson, NY 61.18 mpg

Historic class

1. Bill Clark - 1957 Metropolitan Hartop - Endicott, NY 44.64 mpg
2. Jonathan Bartlett - 1969 Saab Sonett V-4 - Sterling, MA 44.26 mpg
3. Jonathan Schaller - 1968 Saab 96 - Hamilton, NY 37.96 mpg
4. Ron Kienhuis - 1972 Citroën SM - Long Island, NY 32.20 mpg
5. Carl Germain - 1950 Studebaker Champion Business Coupe 27.37 mpg

Motorcycles/Scooters

1. Vlad Saakyan - 2003 Suzuki Svs650 - Niskayuna, NY 62.28 mpg

Average mpg for the whole group: 64.12

Average time to complete the course: 2:38

Event miles: 104


As you can see, we had a nice variety of cars in this event - new and old.

Here's the Honda CRX HF that won the event:



Crazy stuff eh?

More pics and details in THIS thread.

Mike

ABSolute ripper result for the old Datsun!!!
Now if every car had this economy the skies would be clear :)

Looks really good too, prob my favorite 120y for sure very classy.

The winning Honda mainly used tape and perspex mainly mods that
are not really road standard unlike yours. Especially the chihuahua
and granny front pooper scooper. Its reversible though, what a great
way to enjoy cars.

Congrats! That's quite an achievement for old carburetion technology. Well done, I figured you wouldn't get over 70, but you smashed that goal.

I wonder how much more you could get with re-jetting the carb and temperature-controlling the intake -- run the carb real lean.

Very very well done. Im sure I speak for everyone when I say you made the datsun comunaty proud!