weight same as more HP
Safety Car
Joined: Aug 2000
Posts: 4,933
Likes: 30
From: San Rafael CA
Re: weight same as more HP (Z06GMAN)
Yup, you are essentially changing the power-to-weight ratio .....
A car weighing 4000 pounds with 400 HP is slower accelerating than a 3000 pound car with 400 HP (all else being the same ... gearing, wheels, etc.)
Take a look at what Chevy did with the Z06 ... not only more HP, but less weight.
Steve
A car weighing 4000 pounds with 400 HP is slower accelerating than a 3000 pound car with 400 HP (all else being the same ... gearing, wheels, etc.)
Take a look at what Chevy did with the Z06 ... not only more HP, but less weight.
Steve
Supporting Vendor
Joined: Mar 2002
Posts: 2,073
Likes: 0
From: Loveland CO
Re: weight same as more HP (BlackZ06)
For every 100 lbs you drop I think it equals a 10th in the 1/4 mile. So that is about 10 hp per 100 lbs?? Thats just a guess. Kaley
[Modified by 2C5only21, 10:06 AM 2/20/2004]
[Modified by 2C5only21, 10:06 AM 2/20/2004]
Le Mans Master
Joined: Dec 2003
Posts: 5,561
Likes: 448
From: Atlanta metro Ga.
Re: weight same as more HP (Z06GMAN)
Well first I know I need to lose lb's myself :lol: but is there a rule of thumb if you reduce weight on you car as the same as more HP?
It's been my opinion for some time that 3200 lbs for a sports car is (at least) 400 lbs to heavy. But then I read a Road and Track article about the new Porsche GT; here is a no-compromise design for a high performance street car, and guess what? It weights 3200 lbs. So I guess the moral here is if you want A/C, a stereo, and air bags, that's how much a modern sports car is going to weigh.
Pro
Joined: Oct 2001
Posts: 569
Likes: 0
From: Foresthill CA
Re: weight same as more HP (Z06GMAN)
And the power to wt ratio is calculated at max power, so some overlook the fact that losing wt is ALWAYS positively affecting the ptw ratio. In other words, if you only gain top-end increase in max power (like if you extend your rev limit), your ptw will increase of course, but if you drop wt, you will ALWAYS be lighter, even at low rpms/power output. This is most significant when the total wt in the calc is comparatively less, like car vs motorcycle. (Put a passenger on a bike and the ptw ratio goes down rapidly compared to adding a passenger to a car.)
Also consider rotating wt loss has greater effect than non-rotating loss when it comes to accelerating that wt.
Go to a bicycle shop and ask what a "weight weenie" is. :D
[Modified by Stu in CA, 12:42 PM 2/20/2004]
Also consider rotating wt loss has greater effect than non-rotating loss when it comes to accelerating that wt.
Go to a bicycle shop and ask what a "weight weenie" is. :D
[Modified by Stu in CA, 12:42 PM 2/20/2004]
Instructor
Joined: Mar 2002
Posts: 239
Likes: 0
From: Fredericksburg VA
Re: weight same as more HP (Z06GMAN)
Car acceleration=(power)/(mass)/(velocity), or
g's=(HP)*550*60*60/(Car Weight)/(MPH)/5280
So if you cut the weight in half you double the acceleration. Be aware that the power in the equations above is the power used for translation of the car. Flywheel power is also used for drivetrain friction, the acceleration of rotating mass, rolling friction, and aerodynamic losses. As car speed increases less power is used for acceleration of rotating mass and translation, and more power is used for rolling drag and aero drag.
You will notice that engine torque and gear ratios are not in the acceleration equations above. The more power the engine is making, the faster you will accelerate.
g's=(HP)*550*60*60/(Car Weight)/(MPH)/5280
So if you cut the weight in half you double the acceleration. Be aware that the power in the equations above is the power used for translation of the car. Flywheel power is also used for drivetrain friction, the acceleration of rotating mass, rolling friction, and aerodynamic losses. As car speed increases less power is used for acceleration of rotating mass and translation, and more power is used for rolling drag and aero drag.
You will notice that engine torque and gear ratios are not in the acceleration equations above. The more power the engine is making, the faster you will accelerate.
Le Mans Master
Joined: Jul 2002
Posts: 7,076
Likes: 26
From: Nevada and Florida
Re: weight same as more HP (Z06GMAN)
10 lbs = 1 HP. Best to lose weight first. Too bad its not more.
One tip: Get rid of that stock 40 lb battery. I just installed a Odyssey 15 lb dry cell battery, works great.
One tip: Get rid of that stock 40 lb battery. I just installed a Odyssey 15 lb dry cell battery, works great.
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Drifting
Joined: Aug 2000
Posts: 1,253
Likes: 3
From: Chapel Hill NC
Re: weight same as more HP (BHP)
10 lbs = 1 HP. Best to lose weight first. Too bad its not more.
One tip: Get rid of that stock 40 lb battery. I just installed a Odyssey 15 lb dry cell battery, works great.
One tip: Get rid of that stock 40 lb battery. I just installed a Odyssey 15 lb dry cell battery, works great.
Le Mans Master
Joined: Jul 2002
Posts: 7,076
Likes: 26
From: Nevada and Florida
Re: weight same as more HP (tcmc5)
10 lbs = 1 HP. Best to lose weight first. Too bad its not more.
One tip: Get rid of that stock 40 lb battery. I just installed a Odyssey 15 lb dry cell battery, works great.
I think that's a great idea. A 25lb weight savings is significant for me. Would you comment on how you installed it. The dimensions are much different than stock and I need something which will stay put while autocrossing. Did you have to modify anything? Thanks.
One tip: Get rid of that stock 40 lb battery. I just installed a Odyssey 15 lb dry cell battery, works great.
I think that's a great idea. A 25lb weight savings is significant for me. Would you comment on how you installed it. The dimensions are much different than stock and I need something which will stay put while autocrossing. Did you have to modify anything? Thanks.
http://www.odysseybatteries.com/pc680hd.htm
http://www.stealth316.com/2-dynabatt.htm
http://www.gotbatteries.com/
Le Mans Master
Joined: Jul 2002
Posts: 7,076
Likes: 26
From: Nevada and Florida
Re: weight same as more HP (tcmc5)
Thanks, BHP. One more question, are the connectors compatible or is some sort of adaptor required?
