Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Theoretical gains from weight reduction and aero improvements

saand · 10-23-2010, 01:16 PM

Hi All,
There are some modifications which are very hard to test due to the small amount of improvement expected. This weekend i have been attempting to put some numbers to these.

I have seen several threads where people have asked what improvement will i get from weight reduction.

I have used info from the efficiency tool page and some standard equations to find the theoretical improvement based on weight reduction
for anyone interested the method can be found in the following link
Theoretical Weight Energy - EcoModder
feel free to point out mistakes if you see any

For anyone that wants the actual numbers they are in the wiki for weight reduction mod but here is the summary
------------------
Theoretical calculations
For 50kg weight reduction
each acceleration from 0 to 60km/h uses 1.27 ml or 0.00034 gal less fuel

Using this info, if you typically do this acceleration change (0 to 60kph) 30 times for every 100km distance that will use 38ml every 100km

If you are achieving 6 liters per 100km that gives a 0.636% efficiency advantage
------------------

There are may assumptions that feed into this final number however it is a guide for anyone interested in weight reduction

I also have done a similar analysis for aerodynamic modifications, the equations are very simplified though so they are only valid for a few modifications which involve a simple shape in the main air flow path. The perfect candidate for this is the antenna delete so i have written up the method for calculation of the theoretical improvement of antenna deletion

The method is explained in the wiki here
Antenna Efficiency Calculations - EcoModder

I have also estimated efficiency improvements from removal of electrical loads
I have not written up the full method of these calculations however it is only slightly different from the aerodynamic method as everything is converted to watts
final info can be found here
Electrical Loads - EcoModder

So hopefully this info helps some people and hopefully there aren't any errors in the calculations but please speak up if you find any.

10-23-2010, 01:16 PM	#1 (permalink)
saand Wiki Writer Join Date: Jul 2010 Location: Melbourne, Australia Posts: 236 bugler - '91 Mazda 626 90 day: 35.89 mpg (US) Thanks: 15 Thanked 25 Times in 22 Posts	Theoretical gains from weight reduction and aero improvements Hi All, There are some modifications which are very hard to test due to the small amount of improvement expected. This weekend i have been attempting to put some numbers to these. I have seen several threads where people have asked what improvement will i get from weight reduction. I have used info from the efficiency tool page and some standard equations to find the theoretical improvement based on weight reduction for anyone interested the method can be found in the following link Theoretical Weight Energy - EcoModder feel free to point out mistakes if you see any For anyone that wants the actual numbers they are in the wiki for weight reduction mod but here is the summary ------------------ Theoretical calculations For 50kg weight reduction each acceleration from 0 to 60km/h uses 1.27 ml or 0.00034 gal less fuel Using this info, if you typically do this acceleration change (0 to 60kph) 30 times for every 100km distance that will use 38ml every 100km If you are achieving 6 liters per 100km that gives a 0.636% efficiency advantage ------------------ There are may assumptions that feed into this final number however it is a guide for anyone interested in weight reduction I also have done a similar analysis for aerodynamic modifications, the equations are very simplified though so they are only valid for a few modifications which involve a simple shape in the main air flow path. The perfect candidate for this is the antenna delete so i have written up the method for calculation of the theoretical improvement of antenna deletion The method is explained in the wiki here Antenna Efficiency Calculations - EcoModder I have also estimated efficiency improvements from removal of electrical loads I have not written up the full method of these calculations however it is only slightly different from the aerodynamic method as everything is converted to watts final info can be found here Electrical Loads - EcoModder So hopefully this info helps some people and hopefully there aren't any errors in the calculations but please speak up if you find any.