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Discussion Starter #1 (Edited)
Hah!

While planning my amp/sub installation, I gutted my trunk. Removed the spare tire and some other stuff. I also opened my skibag hole and wanted to try how bad I can hear the tire noise like this.

So I took my car out for a spin...WHoaa!! The car felt so much faster! I could spin tires so easily :woot:

I don't think it has actually anything to do with the weight loss other than the fact that I lost a lot of traction. (less weight in the back, hence less traction).

Most propably the car actually is slower as I can't get all the power to the road. (spinning tires). But it sure FEELS fast!!

This is how my car felt before I upgraded from 225's to 255's...

What will happen when I stuff 100lbs of stereo equipment in the trunk...? :dunno: :bawling:

Just wanted to vent...


Here's a pic:

 

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its unlikely that taking the maybe 75 lbs out of your trunk gives you less traction. Lowering the weight will almost always make your car faster...
 

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Less weight is always better. I believe for every 100#'s you gain .1 at the track ... feel free to correct me if I am wrong.
 

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Discussion Starter #5
SaleenS7 said:
its unlikely that taking the maybe 75 lbs out of your trunk gives you less traction. Lowering the weight will almost always make your car faster...
Care to explain?

I say taking 75lbs out of my trunk has bigger effect on the traction than my acceleration.

After all, 75lbs is almost 5% of the total weight on my rear tires. How could that not have effects on the traction? :rolleyes:

I agree with you that less weight is better, but there are other things that also come to the equation. Maybe I should compensate the weight loss (loss of traction) with stickier tires... You get best results when all the little things are in balance together. just my honest opinion. :)
 

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Juha 323Ci said:
Care to explain?

I say taking 75lbs out of my trunk has bigger effect on the traction than my acceleration.

After all, 75lbs is almost 5% of the total weight on my rear tires. How could that not have effects on the traction? :rolleyes:

I agree with you that less weight is better, but there are other things that also come to the equation. Maybe I should compensate the weight loss (loss of traction) with stickier tires... You get best results when all the little things are in balance together. just my honest opinion. :)
When you accelerate, a higher percentage of the weight of the car transfers to the rear wheels than when the car is not moving or moving at a steady speed (that's physics). The 75 lbs you lost out of the trunk is a smaller part of the amount than you are thinking.

Net result is that the effect on acceleration by having less weight to move is greater than the effect on traction by having less force bearing down on the rear wheels.
 

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I'd be careful about doing that. There are two problems with the spare tire removal. One it disrupts the 50/50 weight distribution and although you may be faster in the straights your car will be less planted and harder to control through a corner. Secondly the spare tire was designed to take some of the impact of a rear end collision. Thus more shock will be transmitted into the frame and perhaps cause more damage to the car and injury to yourself.
 

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Discussion Starter #8
slow323ci said:
When you accelerate, a higher percentage of the weight of the car transfers to the rear wheels than when the car is not moving or moving at a steady speed (that's physics). The 75 lbs you lost out of the trunk is a smaller part of the amount than you are thinking.

Net result is that the effect on acceleration by having less weight to move is greater than the effect on traction by having less force bearing down on the rear wheels.

Mind me, but I'm not running the POS stock suspension so my car is not doing wheelies when I accelerate. :lmao:

Though you have a good point there! :thumbup:

Maybe it's just a placebo effect then, but I can definately feel the difference... :dunno:
 

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BMWERKEN said:
I'd be careful about doing that. There are two problems with the spare tire removal. One it disrupts the 50/50 weight distribution and although you may be faster in the straights your car will be less planted and harder to control through a corner. Secondly the spare tire was designed to take some of the impact of a rear end collision. Thus more shock will be transmitted into the frame and perhaps cause more damage to the car and injury to yourself.
I always remove my spare tire at the track. The car is quicker and it also handles better.

Your 50/50 weight distribution is constantly changing anyway, unless you have a car that doesn't happen to burn any gas. Gasoline weighs about 6 pounds per gallon... so the difference between a full tank and empty tank is about 90 pounds.

Also, if your body weighs more or less than estimated for the calculation then the balance is changed, too.

M3's don't come with spare tires :shhh:
 

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Juha 323Ci said:
Mind me, but I'm not running the POS stock suspension so my car is not doing wheelies when I accelerate. :lmao:

Though you have a good point there! :thumbup:

Maybe it's just a placebo effect then, but I can definately feel the difference... :dunno:
It doesn't matter if your car does wheelies or not - the approximately same weight transfer occurs anyways unless you change the location of the rear axle forward or rearward.

The effect of removing the spare on acceleration is not a placebo effect, less weight improves acceleration, period. My car typically runs about 0.1 second faster in the 1/4 with the spare removed than with it in.
 
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