Weight distribution

[polov8]

Does anybody have reliable information on what the weight distribution is of our cars. I'm guessing the 4 cyl cars are closer to 50/50 than the 6 cyl ones?

[croma_man]

very good question, also balancing the 50/50 ratio, was this done in any race e21?

[polov8]

Nobody?

[nas80]

I have a car tilter and if you put it under a bare shell right in the middle it does seem to be evenly distributed as it doesn't take much effort to lift or drop the either end.

However, since fitting the m52 (120kg) and the battery and e12 diff (heavy as) into the boot the car does seem to handle a lot better, the front is still heavier then the rear but not as bad as when it was an m50.

[Jeroen]

Would be interesting to know, we should put a few cars on a set of scales indeed. My guess? Close to 52/48 with a stock 4 cyl setup, worse of course with a 6 cil

[croma_man]

so the battery and the spare improves the distribution of weight with the 6zyl?

[Jeroen]

The 6 cil cars are always overweight at the front, same in the E30. So if you move some weight to the tail like the battery, that helps. That's also why BMW moved the battery to the trunk with the more sporty E30's like the 325i and M3.

[polov8]

Would be interesting to know, we should put a few cars on a set of scales indeed. My guess? Close to 52/48 with a stock 4 cyl setup, worse of course with a 6 cil

That was pretty much my guess. I'm figuring with the battery moved to the rear it'd be close to perfect.

[croma_man]

my opinion, best would be a racing gas tank in the trunk. We have a few trackday E21 on this forums, they know this best.

[nas80]

Would be interesting to know, we should put a few cars on a set of scales indeed. My guess? Close to 52/48 with a stock 4 cyl setup, worse of course with a 6 cil

That was pretty much my guess. I'm figuring with the battery moved to the rear it'd be close to perfect.

the battery weighs - 15?kg - think you might be needing more than that tbh.

ill look into seeing where I can find a weigh bridge. it doesn't give you weight distribution - only overall weight

[nas80]

Calculate the weight distribution of a vehicle using the following steps:

1. Determine the weight and center of gravity location for all of the components and items to be considered.

2. Multiply the center of gravity distance times the weight to get the moment for each component and item.

3. Add all of the moments and divide by the wheelbase to get the weight on the rear axle.

4. Subtract the rear axle weight from the total weight to get the front axle weight.

[polov8]

By deleting the battery from, what, a foot in front of the front axle centreline, and adding it right at the back a similar distance, that's a difference between the before and after axle weights of 30kg, if the car weighed 1000kg, that's 3% of the cars total weight, more than enough to tip the balance ratio from 48:52 to 50:50

[Jeroen]

Yep, from in front of the front axle (weight distribution Audi style) to on top of the rear axle makes more than a 15kg difference indeed.

Always a fight, weight and weight distribution. You don't want to carry too much weight but on the other hand the E21 already is pretty light in the rear. If you really loose a lot of weight there I'd be afraid its becoming too light there and might cost traction at some point.

[problemchild75]

I have a car tilter and if you put it under a bare shell right in the middle it does seem to be evenly distributed as it doesn't take much effort to lift or drop the either end.

However, since fitting the m52 (120kg) and the battery and e12 diff (heavy as) into the boot the car does seem to handle a lot better, the front is still heavier then the rear but not as bad as when it was an m50.

Hmmm I USED to havea car tilter