Is Weight Reduction REALLY that much of a difference?
Thread Starter
Newbie
Joined: Jul 2005
Posts: 67
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From: Snellville, GA
WarrTalon, Thanks a LOT! That is exactly the kind of response I was looking for. Now that makes a lot more sense to me. I had no idea that a pair of subs could cost me a whole car length. Now THAT is a big difference. So then my next question is, when doing weight reduction what are the MOST important areas/items to do? Now notice I said MOST important, I am sure every little bit helps. I know wheels/brakes but where else? Also I dont mean removing the spare, I mean parts you would actually buy a switch out PRIMARILY for weight reduction. Thanks.
-Sayajin
-Sayajin
I agree, concentrate on reducing the weight of moving parts, like rims, flywheel, driveshaft, etc. If you go over the top and start removing interior, your car will look like a peice of crap. $$ go alot farther with performance mods rather than weight reduction, so be prepared to spend alot for a little performance.
Originally Posted by Warrtalon
Bad example. Lighter rims reduce the unsprung weight and make a MUCH BIGGER DIFFERENCE than just dropping 12lbs on the weight of the car. They allow for much faster acceleration plus all the other things Mike@Forge said...
Also, you say you could care less about the 1/4-mile, but the problem is that you don't have any concept of what .1s means in the 1/4-mile between 2 cars and how that translates to the street. I'll give you one example from this past Sunday. I ran a 12.2, and the supercharged 93 Cobra behind me ran a 13.2...a full second slower. This may or may not seem like a long time (1 second), but he was a good 8-10 car lengths behind me? It's hard to measure such a thing when going 110+ and looking in your rearview while slowing down (and your opponent hasn't slowed down yet). Half a second (.5s) is also a very significant difference between 2 cars in the 1/4-mile if they leave at the same moment. In your case, a big sub box could mean a car length difference on the street.
Also, you say you could care less about the 1/4-mile, but the problem is that you don't have any concept of what .1s means in the 1/4-mile between 2 cars and how that translates to the street. I'll give you one example from this past Sunday. I ran a 12.2, and the supercharged 93 Cobra behind me ran a 13.2...a full second slower. This may or may not seem like a long time (1 second), but he was a good 8-10 car lengths behind me? It's hard to measure such a thing when going 110+ and looking in your rearview while slowing down (and your opponent hasn't slowed down yet). Half a second (.5s) is also a very significant difference between 2 cars in the 1/4-mile if they leave at the same moment. In your case, a big sub box could mean a car length difference on the street.
Originally Posted by Sayajin
WarrTalon, Thanks a LOT! That is exactly the kind of response I was looking for. Now that makes a lot more sense to me. I had no idea that a pair of subs could cost me a whole car length. Now THAT is a big difference. So then my next question is, when doing weight reduction what are the MOST important areas/items to do? Now notice I said MOST important, I am sure every little bit helps. I know wheels/brakes but where else? Also I dont mean removing the spare, I mean parts you would actually buy a switch out PRIMARILY for weight reduction. Thanks.
Even though you said not to mention it, take out the spare and tools anyway. Lighter rims help with unsprung weight, which helps launching and acceleration. The BBS rims on the MR help me, but it's hard to say how much exactly.
Replace the battery with a mini-battery. That is a lot of weight. I don't know about brakes and suspension, since I haven't touched those, though.
You are going to get different answers from everyone concerning their methods for weight reduction, so consider ALL of the areas to which this therory can work, and APPLY all that fit within YOUR budget and means.
Most common things to consider for weight reduction:
Unsprung Weight
Wheels
Tires
Brake system (rotors, calipers)
Suspension (coilovers)
Body
Replacing ANY panel with a lighter version
Hood
Trunk
Fenders
Bumpers
Drivetrain
Clutch (negligable improvement)
Flywheel
Driveshafts
Engine
Lightweight battery (or battery relocation to the trunk)
Exhaust (reduce weight while adding power)
Misc.
Removal of any unused or unnecessary components (spare tire, tools, etc.)
Again, everyone will take a different approach to this based on their own needs, so take from it what you will.
Most common things to consider for weight reduction:
Unsprung Weight
Wheels
Tires
Brake system (rotors, calipers)
Suspension (coilovers)
Body
Replacing ANY panel with a lighter version
Hood
Trunk
Fenders
Bumpers
Drivetrain
Clutch (negligable improvement)
Flywheel
Driveshafts
Engine
Lightweight battery (or battery relocation to the trunk)
Exhaust (reduce weight while adding power)
Misc.
Removal of any unused or unnecessary components (spare tire, tools, etc.)
Again, everyone will take a different approach to this based on their own needs, so take from it what you will.
Thread Starter
Newbie
Joined: Jul 2005
Posts: 67
Likes: 0
From: Snellville, GA
Thanks guys. Quick question, how about the BBS rims that come on the MR? I mean those are already considered lightweight rims. Would it be pertinent to change those out as well? Or could you leave those as is?
-Sayajin
-Sayajin
Originally Posted by Sayajin
Thanks guys. Quick question, how about the BBS rims that come on the MR? I mean those are already considered lightweight rims. Would it be pertinent to change those out as well? Or could you leave those as is?
-Sayajin
-Sayajin
Road course/autocross/turning in general = weight reduction does a lot
Drag racing = not so much, sorry, power mods and upgrading to launch the **** out of your car does more (but weight reduction does a lot still, look at the Elise compared to something with equal power)
Drag racing = not so much, sorry, power mods and upgrading to launch the **** out of your car does more (but weight reduction does a lot still, look at the Elise compared to something with equal power)
Originally Posted by Sayajin
Thanks guys. Quick question, how about the BBS rims that come on the MR? I mean those are already considered lightweight rims. Would it be pertinent to change those out as well? Or could you leave those as is?
-Sayajin
-Sayajin
It depends what your goals are. The BBS wheels are quite light... but there are lighter. The BBS wheels are great because they are both light and strong -- actually stronger than the Enkies. This is primarily because they are forged
A point worth mentioning. Everyone is referring to unsprung weight being important. It is and your wheels and brake rotors are unsprung. What is not mentioned is that these also have rotational mass. This is far more important than unsprung weight. A lighter wheel will make much more of a difference than just heavy suspension pieces as it will speed up acceleration as well as improve braking -- kinda like a car that revs up and down much faster due to a lighter flywheel. This is the reason why big heavy bling 19" wheels actually hurt performance – significantly!
Originally Posted by Sayajin
Thanks guys. Quick question, how about the BBS rims that come on the MR? I mean those are already considered lightweight rims. Would it be pertinent to change those out as well? Or could you leave those as is?
-Sayajin
-Sayajin
Last edited by DragNRacing; Aug 24, 2005 at 08:30 PM.
we have tested this over and over and our conclusion is that in 2 cars that cross the 1/4 mile at the same time lets say 13.0 both but one of them looses 85lbs then it makes 12.9sec. this is like 1 car length ahead of the other so .1sec is like 1 car more ahead of the other!!
also for every pound you take off on rotational weight you multiply by the factor #8 and the answer you get is the amount of weight you took from static weight to be more clear if i loose 2 pounds per wheel 2x4 wheels= 8 and 8 x factor#8= 64 so 64lbs of static weight you took off your!!
Evolving Member
Joined: Jul 2005
Posts: 101
Likes: 0
From: Savannah, GA
1lb rotating mass~10lb sprung mass. Eneki RPF1's save 5lb each: total 20lbs. Girodisk rotors save 12lb each: total 48lbs. Equivilant of 68lbs or ~680 sprung lbs. for about $2200. Stop faster, accelerate harder, react quicker; is it worth it? Hell yeah! Lugnuts can save another 5lbs, driveshaft 20lb, pulleys 10lbs, cam gears 5lbs, exedy twin carbon clutch and flywheel 20lbs. This brings our total to 128lb of rotating mass or about 1280lbs of sprung mass. 