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A HP vs weight question???

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Old Jan 28, 2007 | 09:37 PM
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Default A HP vs weight question???

Just wondering how much rwhp it takes to to overcome 100lbs? From my experiences, it takes an '03 cobra about 50whp to pull an f-body. Now, with the f-body about 3400lbs and the cobra about 3600lbs, that roughly 200lbs. So my guess would be about 25whp for 100lbs, does that seem right? Any opinions welcome.
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Old Jan 28, 2007 | 09:42 PM
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Originally Posted by Prey4Me
Just wondering how much rwhp it takes to to overcome 100lbs? From my experiences, it takes an '03 cobra about 50whp to pull an f-body. Now, with the f-body about 3400lbs and the cobra about 3600lbs, that roughly 200lbs. So my guess would be about 25whp for 100lbs, does that seem right? Any opinions welcome.
Although I have no real data. I've been told on multiple occasions that it takes about 10hp per 100lb to travel the same speed.
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Old Jan 29, 2007 | 08:28 PM
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Originally Posted by REDCYCLE13
Although I have no real data. I've been told on multiple occasions that it takes about 10hp per 100lb to travel the same speed.
I have also heard that. I have also heard that taking away 100lbs. would equal about one tenth at the track, so 10whp = .10 of a second? Anybody else have any info or experience?
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Old Jan 29, 2007 | 08:42 PM
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Originally Posted by Prey4Me
Just wondering how much rwhp it takes to to overcome 100lbs? From my experiences, it takes an '03 cobra about 50whp to pull an f-body. Now, with the f-body about 3400lbs and the cobra about 3600lbs, that roughly 200lbs. So my guess would be about 25whp for 100lbs, does that seem right? Any opinions welcome.

Cobras are faster than ls1's stock.
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Old Jan 29, 2007 | 08:50 PM
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100 lbs = 10hp = .10 off the 1/4
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Old Jan 29, 2007 | 09:53 PM
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Originally Posted by 25psi
Cobras are faster than ls1's stock.

SHHH...they dont know that, ALL mustangs are slow.
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Old Jan 29, 2007 | 10:32 PM
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you also have to think about gearing, drivetrain loss, when a car can make its top hp/tq etc....I think those all have a big part too...correct me if Im wrong
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Old Jan 29, 2007 | 11:32 PM
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Originally Posted by Tainted
100 lbs = 10hp = .10 off the 1/4
This is what Ive heard a lot as well.
Its a generalization of course but its good for comparison........I mean bench racing.
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Old Jan 29, 2007 | 11:34 PM
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ive been told its 100lbs = .10 at the strip but im a firm believer that its 115lbs instead...
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Old Jan 30, 2007 | 12:09 AM
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Originally Posted by 25psi
Cobras are faster than ls1's stock.
I know that . What I meant was, lets say, a 400whp LS1 vs a 400whp cobra, it would take the cobra about 50whp to pull the LS1 because of the cobra's 200 pound (+/-) disadvantage. Here is an example,
'02 ZO6 (exhaust)
'03 Cobra (pullied,ported,bolt on's) 580-590whp
'02 Firehawk (H/C,bolt on's) 448whp
The ZO6 has about 200lbs on me, I have about 200lbs on the cobra. Using the formula, it should take me about 50whp to counter the ZO6's weight advantage, while the cobra would need about 100whp to make up for 400lbs. Should a stock ZO6 (w/catback & zip-tie mod) keep up with my car and a cobra making 480-490whp? That would equal roughly 25whp per 100lbs, I'm I correct or way off?
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Old Jan 30, 2007 | 09:01 AM
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i always went with the 100lbs= .1 thing, but the 10hp = .1 thing is not at all correct. you can make 10 more PEAK power but the curve be the same, the car won't be much faster at all. hell the curve could be worse chasing that peak power, to the car is, dare i say, slower...

this all applies to 12 and 11 sec cars too. once you get lower than that it takes a little bit more to go faster. hell in a 13 sec. car 100lbs may give you .2 or more! all cars are different.
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Old Jan 30, 2007 | 09:21 AM
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If you have 448rwhp and 434rwtq, you should easily beat a C5 Z06 with only ziptie and c/b. But then again, on the streets, anything can happen.
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Old Jan 30, 2007 | 10:13 AM
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Originally Posted by 25psi
Cobras are faster than ls1's stock.
no there not I beat them all the time in my lt1 and I get beat by ls1s.

LT1>everything
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Old Jan 30, 2007 | 10:31 AM
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I would say your numbers left out the driver on weights. Figure in an average 200 lb person and the weight difference is the same unless one car has more people. I have actually used 15 hp per 100lbs and do not count the weight factor as a .1 in the quarter. Due to the quicker you go the more it takes to get that .1
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Old Jan 30, 2007 | 11:06 AM
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Originally Posted by Sigforty
I would say your numbers left out the driver on weights. Figure in an average 200 lb person and the weight difference is the same unless one car has more people. I have actually used 15 hp per 100lbs and do not count the weight factor as a .1 in the quarter. Due to the quicker you go the more it takes to get that .1

I agree, I say the general rule may apply to 11s and up, but after that I don't think so. Same applies going very high up on the scale. IF the truck runs 20s, rofl, 100 pounds less weight might get you 3 tenths, hehe.

100 pounds less or 10 more hp = .1 in the 1/4 as a general rule.

Just as Sigforty says, after you start getting really fast, it's going to take more. A good example is those guys runs these 8s and 9s. Going from 8s to 7s, seems to nearly doubling your horsepower. I don't mean from a 8.1 to a 7.9.
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Old Jan 30, 2007 | 01:54 PM
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Drag co-efficientcy is a factor as well. Maybe not at the start of the race, but as you start hitting close to 100 and above it does play a role.
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Old Jan 30, 2007 | 02:04 PM
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agreed!
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Old Jan 30, 2007 | 03:15 PM
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I would have to say that your suspension set up would be the biggest deciding factor in the equation...my frined in okc told me about a car that went 12.3 on a stock no mod l89 that had nothing but suspension work done to it.
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Old Jan 30, 2007 | 03:19 PM
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from what i've seen weight becomes less of a factor at higher speeds as well. lighter weight will get you through the 1/8 quicker, more hp/tq will get you through the 1/4 quicker
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Old Feb 1, 2007 | 10:44 AM
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I noticed the biggest difference on top end when I put my car on a diet. I think it has something to do with the higher the gear the less torque going to wheels so it is easier to accelerate. What is everyone elses experience?
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