Weight reduction
 

I've heard that reducing the weight by 10% will increase the fe by 4-5%, does anyone have any data on this? Also, how much luck has anyone had with actually lowering the weight enough to make a difference. My car is around 3500 pounds so I don't know if I can drop 350 pounds out of it, I might try anyway though.

It's highly duty cycle dependent.
Sort of the inverse of aero.
Weight reduction is most helpful for stop and go.
Aero for cruising speeds.

Rotating weight is even more important for stop and go, but not easily reduced in most cases.

This is a drastic step IMO. I would start off with the small stuff first: Inflate your tires properly, tune it up, modify yourself, read up on techniques...


But here is some really really good information on how weight reduction works. It should help you out on what weight to actually reduce for the best benefit.

EDIT: forgot link...http://www.nissanclub.com/forums/200...e-modders.html

I removed the beackseat in my 94 ford aspire.

The junk weighed 40 lbs
The back seat weighed 42.9 lbs total including the rear rug, ashtray, seat belt bottoms, and rear hatch cover. (9.7 lbs)
I totaled the amount and it came to 82.9 lbs .
Hopefully That will help my MPG

Weight matters a lot in hilly country where the grade term of the road load equation is not zero.

wt/mpg
 

Society of Automotive Engineer research has demonstrated that a 10% wt. reduction would net you an average 3.8% mpg improvement.

In terms of rotating weight (wheels/tires), all else being equal (driving style) how much improvement would there be in FE? I'm looking at at wheel/tire combo that would save 4#/wheel (the more you spend, the lighter the rims, which would take years in FE savings to make up). I know most will talk about the aerodynamic efficiency of the wheels, but I think just having lighter tire/wheels will make the engine strain less both with stop/go and highway driving. The added benefit of improved acceleration/braking and looks is also attractive.

An interesting tool can be found there :

Tool for visualizing aero vs rolling resistance - GasSavers.org - Helping You Save at the Pump

or more precisely here : http://www.geocities.com/frontsidesk8er/delsolaero.xls

You can change weight, CRR, CD & FA and see how the consumption (at constant speed) varies. For me a 10% weight reduction would achieve a 3.3% reduction at the speed I drive the most often.

Have fun,

Denis.

remove everything you deem not necessary from inside the car. seats, carpet, trim, etc thats the free stuff.
if you are a guy who believes in the ends justify the means, you can get lighter tires; lighter rims, lightest ive seen is 12 pounds, replace some or all glass with polycarbonate(lexan); replace ll possible body parts with polyurethane or fiberglass or kevlar; remove the spare, and have AAA handy; switch to lighter racing seats; etc etc, you get my idea. in order to gain 4-5%, you end up spending alot of money, or time for fabrication. you decide.

Totally agree. Although you can get the semi-lightweight stuff for relatively cheap if you search hard enough. I'm down 300lbs in my second car from extreme stripping. still rockin' the stock driver seat, still have 25lbs of sound deadener to remove, haven't changed out to a smaller fuel cell, still using glass instead of poly, haven't finished removing dead weight off the front end. I'm sure I have 100lbs more I can remove. I haven't even brought the grinder out to remove random metal.

Note: ^ Not for the average user ^