as it states whats a "normal" circuit car with cage weigh?
800 ish kilos street car (no cage)
just as long as I don't sit in it 
No.8 Beetle WAS 720Kg, plus driver. A lot more now with roll cage, and it is noticeably slower.
My Hillclimb car was 830kg (WSID scales) plus my weight of 100KG !!!
Heh - TOO MUCH !!!
Two famous Colin Chapman (founder of Lotus) quotes:
- To add speed, add lightness.
- Adding power makes you faster on the straights. Subtracting weight makes you faster everywhere.
From what I've heard 800-850kg is about the norm for a BJ IRS car.... if you can get under that you'll be doing VERY well.
Obviously K+L and Swinger would be a little bit lighter to start with.
craig what have you removed from your hc bug? my 76 has been stripped within an inch of its life with a ten point cage am keen to find out what it weighs theres not much left except about 18 lms of 44.45 cds!
Extra weight is particularly harmful to a hillclimb car. It takes energy to lift an object, therefore - in theory - if two cars have identical
power/weight ratios, and identical drag race times, the lighter of the two will be quicker up a hill!
Looks like K&L&SA is the way to go.
good point but why are all the fast vw times set by bj/irs!!!!!
280kgs :-)
true :-)
Hmmm... not so sure Greg.
My physics is a bit rusty, but here goes:
Power = Work / Time
Work = Force * Distance
Force = Mass * Acceleration
Expanding you get:
Power = Mass * (Accel Gravity + Aero Drag) * Distance / Time
- or -
Power / Mass = (Accel Gravity + Aero drag) * Distance / Time
So if two cars have exactly the same Power/Weight ratio, you can substitute for Power / Mass
(Accel Gravity + Aero Drag 1) * Distance 1 / Time 1 = (Accel Gravity + Aero drag 2) * Distance 2 / Time 2
But gravity is a constant... so the two times become a function of Aero Drag and Distance (ie the lines taken).
Nothing at all about weight !!!
(oh and we all know that BJ IRS beetles let you take better lines)
A lot of fancy stuff there, Dave,
but can you explain
why truckies prefer to park at the top of a hill - or at least on the level - as it means less effort to get moving again?
Heh heh... that's easy.
Have you ever tried to climb into a truck that's parked facing up hill ??? The door always tries to slam shut on you !!!
Not on a Tempo Matador they don't !
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in 1999 I did a lot of homework and research into how I could lighten the WPVW sports sedan to prepare it for the 2000 NSW & Australian Hillclimb
championships . I cut out all the double panels (except door pillars) , fitted lexcen to all windows , cut passenger seat runner from pan , even went
to the extent of purchasing 100 aluminum bolts which were all used in the sports sedan with a total saving of 750grams . The most important
improvement was the alloy super-lite race wheels , 15x10's up front & 16x11's at the rear weighing in at just 6 kilos per rim .
As it had been logbooked by CAMS prior to december 1998 it is approved with an aluminum cage , so in 2000 I contested and won both the NSW &
Australian hillclimb championships in the sports sedan 2001-3000 class with a weight of 640kg . Add to that my weight and the race weight was 740kg ,
with 181bhp @ the wheels .
In 2002 rule changes were implemented for sports sedans and I had to add 160kg to the WPVW sports sedan to comply with the 2842ml engine . I did this
by removing the 6-point aluminum cage and manufacturing a full steel cage from bumper to bumper . I borrowed a set of V8 supercar digital scales and
relocated battery , dry-sump oil tank etc to get my corner weights as close to perfect as possible with the rear engined car .
I did acheive the desired results and the WPVW sports sedan had increased in weight to 805kg . I raced in this format for only 4 race meetings and
then competed at the 2003 Australian hillclimb championships , were I found that the rule changes were not being followed by anyone in the sports
sedan category . I came 2nd (by 0.2sec)to a Ford Anglia powered by a mazda rotary and the Anglia had no roll-cage at all fitted (just a single
rollover hoop) and was clearly 200+ kg lighter than my car .
I returned home from the Australians in 2003 , cut the entire cage from the sports sedan ( which I still have stored) and fitted a full aluminum cage
from bumper to bumper . I still made the WPVW sports sedan legal by reducing the engine size to 2440ml (still the same engine as being used now) and
making it comply with a weight of 700kg . With the driver 800kg ...
and that is how it still stands today
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Sides quote of Chapman was good, as any lower weight means you can brake later into a corner and corner faster, the car will be better on its tires.
Its intersting in the tarmac rally's drivers want the lightest nav possible, but then are 15kg overweight thenselves!
THe L bug should be fully stripped for the first time later this year (always just been rear seat and thats it), will be interesting to see what I can
get it down to before starting on the other stuff like alloy's rather than steel wheels, cage add etc
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