C6Z corner weights

[ghoffman]

I scaled my new C6Z today, the total weight with a completely full tank was 3186 pounds so figure 16 gallons at 7.4 pounds per gallon means it is 3068 pounds empty! It was 51% front, 49% rear, 49.5% left, 50.5 % right with no driver. The front caliper was 7 pounds with no pads, and the front rotor was a rediculous 25.5 pounds! For reference, a Wilwood 14 x 1.25 rotor is 17 pounds without hat and the hat is 1 pound.

[Zlicious]

Originally Posted by ghoffman

I scaled my new C6Z today, the total weight with a completely full tank was 3186 pounds so figure 16 gallons at 7.4 pounds per gallon means it is 3068 pounds empty! It was 51% front, 49% rear, 49.5% left, 50.5 % right with no driver. The front caliper was 7 pounds with no pads, and the front rotor was a rediculous 25.5 pounds! For reference, a Wilwood 14 x 1.25 rotor is 17 pounds without hat and the hat is 1 pound.

Great. Thanks for the info

[AndyZ06]

It sounds like GM not only underrated the power of the car, they also had a better weight than published.

With the ~455 rwhp avg, we're not really talking about a 505 hp 3130 lb car. It's more like a 535 hp 3070 lb car.

[ghoffman]

BTW, I have the 2LZ package...

[Zlicious]

Originally Posted by AndyZ06

It sounds like GM not only underrated the power of the car, they also had a better weight than published.

With the ~455 rwhp avg, we're not really talking about a 505 hp 3130 lb car. It's more like a 535 hp 3070 lb car.

[TetraU]

GM probably used half a tank of gas as the measuring point for the weight. A car without gas can't move. So the 3130 wieght is pretty accurate. Who's got a 1LZ? I bet the weight will be 3030 without gas. IT should be real easy trying to knock off some more weights for this great vette.

[GlennSullivan]

Originally Posted by ghoffman

BTW, I have the 2LZ package...

Wow

I can't wait to get my 1LZ on the scales.

BTW I promised myself and my wife that I wasn't going to mod THIS car, but for those of you with no promises, some lightweight rotors could knock off another 30 or more LBs

[andym]

Originally Posted by AndyZ06

It sounds like GM not only underrated the power of the car, they also had a better weight than published.

No, it means they are pretty accurate.

1. Gas doesn't weigh 7.4 pounds per gallon
2. Car manufactures don't quote dry weight they quote curb weight

GM would not deliberately get the cars weight wrong

[E55er]

great info... a gallon weighs approx 6.25lb so close enough. for each 4 lbs of unsprung weight you lose you gain a theoretical 1 hp. so besides better handling, some nice two-piece rotors would gain 8hp.

[amriche]

Anyone weighed the rims yet??

[blackc6]

Originally Posted by E55er

great info... a gallon weighs approx 6.25lb so close enough. for each 4 lbs of unsprung weight you lose you gain a theoretical 1 hp. so besides better handling, some nice two-piece rotors would gain 8hp.

do you mean "rotating weight" rather than "unsprung weight"?

[E55er]

Originally Posted by blackc6

do you mean "rotating weight" rather than "unsprung weight"?

no, its unsprung weight for cars when talking about cars and generally rotating weight when talking about bicycles or rotational weight when talking about driveline components in cars too.

Unsprung weight
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Unsprung weight is a term used to describe that part of a vehicle's mass that is directly connected to the wheels, and not isolated through the suspension. Unsprung weights typically consists of the weight of the wheels, tires, brakes (if within the wheels), spindles, bearings, and a portion of weight of the half-shafts, springs, and suspension links.

Because this part of a vehicle is in direct connection to the road and therefore subject to all of its imperfections, it is important that this weight be as low as possible, or at least much lower than the weight of the sprung part of the vehicle, in order that the wheels maintain optimal contact with the road surface. The greater the unsprung weight, the greater the inertia of the suspension, which will be unable to respond as quickly to rapid changes at the interface between the road and wheel. Unsprung weight can be reduced by using light alloy wheels, independent rear suspension on rear and all wheel drive vehicles (where the weight of the rear differential is not part of the unsprung weight) (also obtained by the use of front-wheel drive) and the location of brakes inboard rather than within the wheels.

The classic design of rear-wheel drive through a live axle ("Hotchkiss Drive") gives quite a high unsprung weight, which is one reason why it has fallen out of favour for anything other than trucks. The use of independent rear suspension allows the handling and response under acceleration and braking to be finely tuned. The Hotchkiss Drive has one significant advantage in that very high power can be transferred to the ground with less tendency to induce wheel hop and so is favored in drag racing. This advantage also accrues to a similar rear drive suspension, the de Dion. The de Dion uses a rigid beam to connect the rear wheel bearings and uses half shafts to transmit power from a chassis-mounted differential, reducing the unsprung weight. A recent vehicle using this suspension was the Ford Ranger EV which had a an aluminum beam on leaf springs and a chassies mounted geared electric powertrain unit located between the rear wheels.

The basic balance is between the ability of the suspension system to supply reactive forces to the mass of the unsprung weight in order to counteract the forces supplied by road surface imperfections. Heavy unsprung weight can overload a suspension systems ability to react, leading to tire hop, slapping, poor traction & bad ride and handling.

another equation is 1 pound of unsprung weight equals approx 4 pounds of sprung. eliminate 32lbs plus hopefully 20 lbs from lightweight titanium fastened wheels from hre and youve effectively lost 210 pounds ish. well on your way to a sub 3000lb car. which i am trying to do by the way.