new rims--->16.5 pounds
Suzuka Master
Joined: Nov 2000
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From: Ninth Gate & So Cal
Originally posted by unsure
eric, do u know the tire weight 4 the toyos in 225/45/17 config? thanks
eric, do u know the tire weight 4 the toyos in 225/45/17 config? thanks
20.9 lbs
Suzuka Master
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From: Woodstock, GA
Originally posted by moomaster_99
Depends...I think on 15-14 sec. cars its a 100lbs.... as you go faster....you need to lose more weight or gain more hp as it takes more power as speeds go up....everything is relative...
Depends...I think on 15-14 sec. cars its a 100lbs.... as you go faster....you need to lose more weight or gain more hp as it takes more power as speeds go up....everything is relative...
Now take a 3000 lb car with 120 lb/ft at 5k revs (but 220 HP at 8k revs), add 100 lbs and you might see an ET two tenths (or more) slower.
Banned
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From: Somewhere between here and there, yet neither.
Originally posted by scalbert
Actually is has more to do with the base weight and torque output. Imagine a 6000 lb truck with 500 lb/ft at 2k revs that can run a mid 15 second ET. Add 100 lbs to it and it won't even notice it.
Now take a 3000 lb car with 120 lb/ft at 5k revs (but 220 HP at 8k revs), add 100 lbs and you might see an ET two tenths (or more) slower.
Actually is has more to do with the base weight and torque output. Imagine a 6000 lb truck with 500 lb/ft at 2k revs that can run a mid 15 second ET. Add 100 lbs to it and it won't even notice it.
Now take a 3000 lb car with 120 lb/ft at 5k revs (but 220 HP at 8k revs), add 100 lbs and you might see an ET two tenths (or more) slower.
Suzuka Master
Joined: Nov 2000
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From: Ninth Gate & So Cal
Originally posted by moomaster_99
Depends...I think on 15-14 sec. cars its a 100lbs.... as you go faster....you need to lose more weight or gain more hp as it takes more power as speeds go up....everything is relative...
Depends...I think on 15-14 sec. cars its a 100lbs.... as you go faster....you need to lose more weight or gain more hp as it takes more power as speeds go up....everything is relative...
You could have a 2000 lbs car and removing 100 lbs is quite nice.
You could have a SUV and removing the 100 lbs is almost undetectable.
Depending on the acceleration in the 1/4-mile and weight, the gain can be all over the map.
If anyone wants to "play" with the figures -- go here:
http://www.prestage.com/carmath/calc_etmph.asp
The problem with these "calculators" is they don't factor in a TON of factors like wind resistance (just for a start).
If you start with 200HP and 3500 lbs, it looks like the ET keeps increasing with each 200 lb drop. Here are some numbers:
Code:
weight whp et drop trap speed ------------------------------------------------ 3500 200 15.11 - 3300 200 14.82 0.29 3100 200 14.51 0.31 2900 200 14.19 0.32 2700 200 13.86 0.33 98.36 2500 200 13.51 0.35 100.91 2300 200 13.14 0.37 103.75 2100 200 12.75 0.39 106.94 1900 200 12.33 0.42 110.57 1700 200 11.88 0.45 114.75 1500 200 11.39 0.49 119.62 1300 200 10.86 0.54 125.46 1100 200 10.28 0.58 132.64 900 200 9.61 0.67 141.81 700 200 8.84 0.77 154.18
As anyone can see, the percent drop in weight is increasing in proportion to the total vehicle weight. However, this calculator DOES NOT account for CD (coefficient of drag) and wind velocity. The end of speed MPH are the bottom are great if the car has no near zero frontal area and ultra low CD..
Look at the last figure and tell me that this is correct if you have a 200HP, 700-lb go-cart with the frontal area of a Meto/RTD buss (Trap speed of 154.18. I don't think so...)
The fixed numbers (xx-seconds per lbs of weight loss) are useless without context -- and beware of the calculators. They are good for "moving" small numbers around, but have some serious limitations...
Moderator Alumnus
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From: Lenexa, KS
Originally posted by moomaster_99
Depends...I think on 15-14 sec. cars its a 100lbs.... as you go faster....you need to lose more weight or gain more hp as it takes more power as speeds go up....everything is relative...
Depends...I think on 15-14 sec. cars its a 100lbs.... as you go faster....you need to lose more weight or gain more hp as it takes more power as speeds go up....everything is relative...
I assume you've tried this at the track to make the statement?
Kinda like it takes a bit of power to drop into the 13's. Take a whole lot more to get into the 12's. And a bunch more to get into the 11's... 9's is insane ammount of HP
It's not a linear graph. And its about 170LBS per .1/sec on a car 3000lbs+
But ya, it's very relative...
Thread Starter
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From: OR
it would be silly of me to buy the lightest 18" wheels available and not get the lightest tires to match.
so if the t1s's are the lightest, thats what i'll get.
also, a good portion of the weight savings of these wheels is the rim itself, which is a good thing, since it's the outer most portion of the wheel. forged is a good thing
so if the t1s's are the lightest, thats what i'll get.
also, a good portion of the weight savings of these wheels is the rim itself, which is a good thing, since it's the outer most portion of the wheel. forged is a good thing
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