<VV> Re:Moving the battery to the trunk

[Shaun]

Hi John, I doubt I'll make it to Detroit, but:
anything that you can do to make our beloved cars closer to 50/50 weight distribution will make a big difference. I don't know much about moments of inertia, except that if both front and rear are even, all 4 tires will work together. No pendulum action. Like Warren said, the fronts are underloaded and the rears are overloaded. 
The best handling race cars have a 50/50 weight dist. The ones that don't, eg. F1 etc... have wider tires on the back so that in a corner, the weight on the tires, corrected for sq. inches of contact patch, are equal. I think if you figured out the ratio of tire widths on an F1 car, you'd have exactly the same ratio of front to rear weight bias.
So, the quickest, most effective way of making a Corvair have an effective 50/50 ratio would be to put wider tires on the back.
That said, the driver is the most important factor in an autocross. A fast driver in a slow car can beat a slow driver in a fast car. 
So, if I do make it to Detroit... how about that same wager with both of us driving your car?<G> 
Or I could try to find a ride in a fairly fast Early Model with the battery in the trunk, and kick your Late's butt!

yea, Vairily ... Shaun

----- Original Message ----- 
  From: John Kepler 
  To: 'Shaun' 
  Sent: Saturday, October 21, 2006 11:46 AM
  Subject: RE: <VV> Re:Moving the battery to the trunk


   

   

  -----Original Message-----
  From: Shaun [mailto:shaun_mcgarvey at shaw.ca] 
  Sent: Saturday, October 21, 2006 1:22 PM
  To: John Kepler
  Cc: virtualvairs at skiblack.com
  Subject: Re: <VV> Re:Moving the battery to the trunk

   

  John, your credentials are impressive, but in simplistic terms:

   

  A pity racing cars aren't all that simplistic!

   

  If you have a 2000 lb. car with 1000 lbs on both front and rear, remove the

  30 lb battery from the back, now 970 lbs.,  and put it in the front, now

  1030 lbs. you get a 60 lb. weight difference, balance-wise 1030-970=60

   

  the same as adding 60 lbs. to the front, or removing 60 lbs. from the rear.

  How can you deny that?

   

  I'm not denying the factoid....just its significance, which in this case, is totally misleading at best!  You are looking at a static condition in a dynamic system.....making your numbers a difference without ANY significant distinction!  It's known as making a 5 dollar conclusion out of a nickel's-worth of data, and is just one of the reasons why you put cars on a track....rather than just submitting a list of numbers and assigning a winner based on the data sheet!

   

  FWIW, the LOCATION of the mass is far more important than the static weight bias, eg:  30 lbs of mass re-located in the physical center from EITHER end of the car will have more benefit than having 30 lbs simply swap ends, regardless of what it does to the static weight bias!  Engineering Dynamics 101.

   

  If I get my Corsa done for Detroit.....I can give you an empirical demonstration....."loser" buys the first round (Waterford has a bar ya'know!)!

   

  John