We've discussed this several times but in doing some research and the weights allowed by some vintage groups and the FIA spec from back in the day, I'm trying to figure out how on earth you get a 1200 with a proper cage to weigh 1410-1480lbs.

Currently my coupe is at 1690lbs: this is without all the lights and bumpers, door glass, window mechs, no back seat and Lexan side windows. The cage is probably around 130lbs as it as several extra bars (3 door bars on each side plus 2 extra diagonals) Also I know the 280ZX struts/ brakes are adding a wieght. Note I'm running an A12GX

So what does "your" 1200 race car weigh

Is it possible that most of the cages 'Back in the day" were fabbed out of alloy, and could also only been a half cage?

benny is right on there unless your cage is also alloy.

The other area is the drilling away of unwanted weight like bonnet support frame and other bits.

Simple things like non overengineered brakes eg avoid 13inch rotor with quad pistons caliper setups. Im sure you havent gone this way.

I remember a NZ 1200 coupe owner had his down to 590kg using swiss cheese techniques and when it crashed the thing collapsed like a tissue yet driver remained safe due to the cage.

The CAMS legal steel cage in the old 1000 sedan tipped the scales at 80kgs.It was 1 diaganal on the main hoop,2 back braces,taxi bar,single hip bars on both sides to the front hoop and no cross bar behind the dash,so i think you need to add quite a bit to your estimation.

780kgs. (1716lbs)

That's the min. weight I'm allowed in the class I run, so that is what it weights.
Very easy to do.
Even had some weight to put where I wanted it for ballance.

Class 3D sports sedan 1600cc-2000cc (98-122 cubic inches)

Cheers,

Geoff

Ps. That includes driver.
car only, 700Kgs (1540lbs)

Rallytwitt, Sounds like your 1200 is a bit on the heavy side.
My Coupe is less than that with full glass, bumpers, turbo, intercoolers, dry sump sys., full cage, lights, dash Etc.

Did you try to build it light?

I weighed everything before i put it on the car and asked myself, can this be made lighter? EG. did you know that a H4 headlight is 90 grams lighter per side than a sealed beam unit. I removed 100grams per fuel rail in the milling machine. might sound silly but if i do this 100 times as i build the car its 10KG.
I supose it depends how important weight is to you and to me, it`s important.

EDIT: I think a 1410-1420lb coupe would be posible but would involve a lot of engineering.

After reading Berts reply I went back and did just a quick/rough measurement on how much tube was in the car and there is at least 70 feet of 1 3/4 .120 wall tube. At 2 pounds per foot that would be 140lbs and that doesn't even include the seat back braces, gussets and the 8 inch by 8 inch plates at the 8 mounting points (I thought the shipping weight on the original cage was 120ish pounds but hey that was 19 years ago) so yeah I'd say the cage is probably in the 160-175lb range.

Now a back in the day alloy or smaller moly-tube cage would likely be half that, bring the car down to 1610, then take out the passenger race seat, harness and window net, takes out another 25-30lbs, the ZX brake/strut set up is probably 20lbs extra, super light weight wheels 15-20lbs, dry battery 20lbs, lighter hood/trunk/doors, lexan rear window 35lbs etc, alloy brake drums and all the other stuff they did and OK I can see how the got to the 1450 range.

When the cage was done I cared more about protecting the driver then weight, the upgrade was done to meet Rally America specs in anticipation of a tarmac rally....which never happened. I still have another 40-50lbs that I can shed fairly easy.

Well I think I know what I'll be doing over the summer (it's 40-45 degree in Vegas June to August so it's our off season)..........anybody got an Alloy block for an A12?????

Tom

Hi Tom
We have an MX5 (Miata) series here in Australia that is very competitive. This leads to all sorts of engineering ideas.

Apart from swiss cheesing all of the brackets and running dry cell miniature batteries one of the most amazing tricks I have seen is the centres drilled out of all of the bolts.

my bloody goodness drilling bolts is getting pretty hairy!!

In the old forum there is a sub 600kg 1200 coupe from a new zealand racer
he used to post often in the past but havent heard much of him since he
had a scuffle with a zealous member. Its a shame we welcomed his insight.

We have a Spec Miata series here in the States but the minimum weight and rules are such that no one has to go to crazy lengths..........having raced a Miata I can tell you they are very fun.

As for drilled out bolts, with my bike background I can say this is nothing new. My 30 yr old MX bike has a couple of hollow bolts on it from the factory as well as some titanium. You can actually buy hardware that has been machined with maximum lightness in mind. Ever notice the dished out heads on motorcycle race bikes and socket head bolts weigh less then the regular...........these are bikes trying to shed mere pounds.

Needless to say the whole Lotus-ifying of a 1200 could get really pricey.

Tom