|
A-B-A with different weights.
I finally decided to some A-B-A tests with different weights in my Metro.
Because I do P&G it would be very hard for me to be consistent with regards to acceleration rates and shifting gears. I opted for increasing the distance to help even out the inconsistencies.
I did my testing using LOD of 34 to accelerate up to 55 MPH then coast engine off till 40 then accelerate again. I drive this road often and have specific markers to start coasting and to start accelerating when it is more efficient. I started outside of one town and stopped before the next town so there were no restrictions from stop signs or lights. I drove totally in the emergency lane so traffic was not a factor at all.
I got some canvas bags, and filled them with sand (454 pds). With the spare tire and other thing in the car the weight I removed between tests 510 pds. My two places (E and M) to stop and turn around were 22 miles apart, and had a 200 hundred foot difference in altitude. The wind was blowing from E to M at 8-10 MPH, and remained steady throughout the test. I filled the gas tank, and put all tires at 44 PSI. Here are my weight load, average speeds and MPG for each run.
E -> M Light-- 46 MPH 81.6 MPG
M -> E Light-- 43 MPH 54.8 MPG
E -> M Heavy- 44 MPH 87.4 MPG
M -> E Heavy- 43 MPH 53.2 MPG
E -> M Light-- 45 MPH 86.5 MPG
M -> E Light-- 43 MPH 54.6 MPG
This shows almost no advantage to either being light or heavy. I tried another test that was A-B-A going on a more level road only in the one direction. This leg was 9.7 miles.
E -> A Heavy- 43 MPH 73.5 MPG
E -> A Light-- 44 MPH 75.0 MPG
E -> A Heavy- 44 MPH 76.8 MPG
I conclude that with my driving style, it doesn't matter whether I am heavy or light. Being light makes it easier to P&G because less shifting is required. When heavy, I used third gear to accelerate from 40 MPH.
Only with large altitude differences will I be concerned about weight in the future.
|