Weight or Power?
05-07-2007, 05:35 PM
#1
Drifting
Thread Starter
Weight or Power?
What would you rather have, 20% more power or 20% less weight?
I'm getting started on a 911 racecar project and I have a couple of options to consider. In the class I have in mind I can have a 2650 pound car with around 220 HP, or a 2200 pound car with about 180 HP (weights include driver). Either car will be identical (aero, suspension, tires) other the power plant - the only differences will be the power and weight. I know the best combo is track dependent but I am looking for the best all around performer.
Right now I am leaning towards building the lighter car. I feel that the lower weight will help me all around - acceleration, braking, and cornering; while the extra power will only help me accelerate. The lighter car should also be easier on consumables like brakes and tires. I have been pretty impressed with some of the lightweight vintage 911's that race out here, although most of them have high dollar race motors they are only 2 litres, and they are really quick running on skinny 225 rubber.
What would you build and why?
I'm getting started on a 911 racecar project and I have a couple of options to consider. In the class I have in mind I can have a 2650 pound car with around 220 HP, or a 2200 pound car with about 180 HP (weights include driver). Either car will be identical (aero, suspension, tires) other the power plant - the only differences will be the power and weight. I know the best combo is track dependent but I am looking for the best all around performer.
Right now I am leaning towards building the lighter car. I feel that the lower weight will help me all around - acceleration, braking, and cornering; while the extra power will only help me accelerate. The lighter car should also be easier on consumables like brakes and tires. I have been pretty impressed with some of the lightweight vintage 911's that race out here, although most of them have high dollar race motors they are only 2 litres, and they are really quick running on skinny 225 rubber.
What would you build and why?
05-07-2007, 05:43 PM
#2
Drifting
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Definitely lighter for all of the reasons you listed...same power/weight = same acceleration, but lighter weight means the car will corner and brake better. Also, try to use a motor setup that will get you that peak hp # you need while maximizing area under the curve. HP doesn't win races, power under the curve does.
05-07-2007, 05:51 PM
#4
Drifting
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Originally Posted by Bailey-86-MA
Slightly greater power to weight ratio in the lighter car.
05-07-2007, 05:54 PM
#6
Rennlist Member
Originally Posted by Bryan Watts
Definitely lighter for all of the reasons you listed...same power/weight = same acceleration, but lighter weight means the car will corner and brake better. Also, try to use a motor setup that will get you that peak hp # you need while maximizing area under the curve. HP doesn't win races, power under the curve does.
05-07-2007, 05:59 PM
#7
Three Wheelin'
Personally, I would take the lighter car. It will out perform the heavy car in most categories, but there is a point where price and amount of work come in to play. Is it going to be more expensive and time consuming to get the motor to 220 hp or to get the chassis to 2200 lbs? Any left over funds get to go towards better/more tires, brakes, different springs (depending on whether you're on torsion bars or not and the feasibility of swapping), etc.
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05-07-2007, 06:04 PM
#8
Nordschleife Master
Power/weight governs handling, braking and launch out of the turn. Peak hp does matters for top end. If you raced at Daytona, you'd want the 2650/220 car. At most other tracks, you'd want the 2200/180.
05-07-2007, 06:10 PM
#10
Drifting
Thread Starter
It is cheaper and easier for me to make the car light so that is part of my motivation too. Fiberglass parts are a lot cheaper than 911 engine swaps.
Would your answer change if I said half of my racers will be at Willow Springs and Cal Speedway (both are "fast" tracks)?
Would your answer change if I said half of my racers will be at Willow Springs and Cal Speedway (both are "fast" tracks)?
05-07-2007, 10:11 PM
#14
Formula One Spin Doctor
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The lighter car , less load on the tires and brakes , bigger advantage over the race distance ..... A really nice race car weight is 1800 lbs , 2600 will feel like a truck...
05-08-2007, 04:10 AM
#15
Race Director
Since the power/weight difference isn't very much.....I would go for the lighter car.....with only a .2 difference in power/weight the 450lbs lighter car will turn better lap times!