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Power to weight questions

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Old Dec 27, 2012 | 06:01 PM
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Default Power to weight questions

Looking at losing some weight in a potential new project and had a power to weight question. Assuming both cars are fully cross balanced and the same "un-sprung weight" (wheels, tires, rotors, etc...) will be removed from both options:

Is there a difference in having a 2,800 lbs. with 280 whp (giving a 10.1 pwr/weight)

vs

having the same car at 2,200 lbs. with 220 whp (giving a 10.1 pwr/weight)

Thanks guys
Old Dec 27, 2012 | 06:11 PM
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All other factors being equal the lighter car should be faster on the track.
Old Dec 27, 2012 | 06:14 PM
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The lighter car will obviously have advantages under braking and turning. The higher powered/heavier car will have advantages up top where aero becomes more of a factor, then again... 600lbs is alot in a miata.. Goals for the project?
Old Dec 27, 2012 | 06:15 PM
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yup....more power wins in the straights, less weight wins in the corners/braking
Old Dec 27, 2012 | 06:18 PM
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Option C: 280whp with 2,200 lbs?
Old Dec 27, 2012 | 06:20 PM
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looking at replacing my NA track preped miata with a 99 NB. Turbo, suspension (where applicable), seats, brake parts, etc. will be making the move to the new car.

NA looks beat to **** and has been through hell and back. Im getting the 99 MB with a non-running engine (dont know whats wrong) for $800. Body is straight and looks clean. Benefit will be having A/C and a roof on my way home after our long 120* track days here in AZ and on the way Cali


Originally Posted by LukeH
Option C: 280whp with 2,200 lbs?
Cant do option C due to TT and Time Attack reasons.
Old Dec 27, 2012 | 06:30 PM
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I don't think an NB weighs 2800lb even fully dressed
Old Dec 27, 2012 | 06:38 PM
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I'm not sure even an NC weighs that much.
Old Dec 27, 2012 | 06:38 PM
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Are you adding in driver weight and ballast to meet a class requirement?
Old Dec 27, 2012 | 06:50 PM
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i was using fake numbers, sorry for the confusion. Yeah car is classed on the cusp for both TT and time attack.
Old Dec 27, 2012 | 07:03 PM
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Age-old question, and the answer of which is better probably depends on a lot, varies from track to track, etc.

The heavier car with more power is easier to go fast in. The lighter car with less power takes more work and less mistakes to do the same lap time with.
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Old Dec 28, 2012 | 01:34 PM
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The lighter car will also be easier on tires, brakes, etc...

Don't forget about the power band. It makes a huge difference in HP/weight limited classing.
Old Dec 28, 2012 | 05:37 PM
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My NB2 weighs 2600 even with the rollbar, FM hitch, rotrex + intercooler etc, and the hardtop on. Full interior, leather seats, power windows, etc. No lightening has been done. This was at my last corner weighting in October.

If the cars are equivalent (aero, tires, suspension) then the 2200/220 car will be faster on track.
Old Dec 28, 2012 | 05:41 PM
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2600.....Not bad IMO. Sport brakes and SE bracing by any chance?
Old Dec 28, 2012 | 05:48 PM
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Originally Posted by Mobius
My NB2 weighs 2600 even with the rollbar, FM hitch, rotrex + intercooler etc, and the hardtop on. Full interior, leather seats, power windows, etc. No lightening has been done. This was at my last corner weighting in October.

If the cars are equivalent (aero, tires, suspension) then the 2200/220 car will be faster on track.
is that with or without driver?
Old Dec 28, 2012 | 10:25 PM
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That is the car without driver. Full tank of gas. Car had OEM sport brakes and ABS; it now has TSE BBBK up front.

It was corner weighted with me in it, of course, but it came to 2600 even without me.
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