Lowering your car in order to increase fuel economy

[SVOboy]

W00t, I'm excited. Yeah, I was in shorts and a t shirt today and sweating, I hate the summer, grr.

On another note, all my stuff is in the mail to fix the car (I hope) so hopefully I can get that done and go run up and get that transmission and you can be like, 70 mpg, *smack*

[krousdb]

[quote=krousdb]OK, the last leg of the tank. I had a 12MPH cross wind, not sure it f hurt or helped.

- 3/10/06 Evening Commute: 53F, WET roads, 12 MPH CROSS wind, engine on 78% of distance, 54.16 MPG.

- Current Tank FE as measured by SuperMID
575 miles, 52.56 MPG, or 55.0 MPG as measured by the Digital Fuel Gauge.

I will fill tomorrow morning.

[krousdb]

The numbers below are corrected for the SuperMID error.

Pre Drop km/L km Temp MPG
2/28/2006 21.90 40.61 18 51.52
2/28/2006 21.24 42.33 41 49.95
3/01/2006 24.20 40.57 28 56.93
3/01/2006 22.61 42.10 41 53.19
3/02/2006 23.86 40.57 30 56.12
3/02/2006 21.50 42.34 41 50.58
3/03/2006 21.17 40.56 18 49.79
3/03/2006 20.73 45.90 39 48.75

Pre Drop ave temp 30.90F
% distance on wet roads 60%
Pre Drop ave FE 52.01MPG

Post Drop km/L km Temp MPG
3/06/2006 25.68 40.57 30 60.41
3/06/2006 22.40 42.24 40 52.68
3/07/2006 24.30 40.52 21 57.15
3/07/2006 23.09 42.26 39 54.32
3/08/2006 23.89 40.55 28 56.19
3/08/2006 23.85 42.26 41 56.10
3/09/2006 24.46 40.46 44 57.53
3/09/2006 25.06 42.20 64 58.94
3/10/2006 24.66 40.48 53 58.00
3/10/2006 23.83 42.21 53 56.06

Post drop ave temp 41.3F
% distance on wet roads 30%
Post Drop ave FE 56.74 MPG

I would say that given the variables of temp, wet roads, varying winds and lower ride height, one cannot extract the effect due to lower ride height alone. I would suspect that most of the gain came form warmer temps and dryer roads.

[Matt Timion]

I'll run this data later today and see if the temperature confounds the MPG or not. I'm guessing it actually won't. I say this based onthe fact that the temperature on many times goes down while the fuel economy goes up. Give me a few hours to get around to it.

[rh77]

Originally Posted by SVOboy

W00t, I'm excited. Yeah, I was in shorts and a t shirt today and sweating, I hate the summer, grr.

You know what, I agree -- summer is not my favorite season wither. It was barely 70 today and I was sweating like crazy -- and I wasn't going to run the A/C in the car -- so around town it was fine with the windows down, but on the highway I subscribe to the theory that the drag induced is too much unless it's baking, then the A/C comes on. So to preserve good mileage, I had to use the vent blower, which was blowing out warm air for some reason. I had to crack the windows about a half-inch. Increased the Cd slightly (but not as much as the compressor, probably).

RH77

[SVOboy]

Not to mention that the summer in MO is friggin brutal. I'm out working on the farm in that crap too. One day I weighed myself in the morning, went to chop some trees out of the fenceline, came back at like 5pm, and I weighed 17 pounds less (and that included all the sweat still lodged in my clothing).

[rh77]

Originally Posted by SVOboy

Not to mention that the summer in MO is friggin brutal. I'm out working on the farm in that crap too. One day I weighed myself in the morning, went to chop some trees out of the fenceline, came back at like 5pm, and I weighed 17 pounds less (and that included all the sweat still lodged in my clothing).

I bought my Civic DX without air when I lived in Ohio, and it got hot, but was manageable. When I moved to KC, it was so hot and humid in the summer, I'd be soaked by the time I got to work -- not really good for career advancement -- bought an OEM A/C kit and it bolted right in. That button was such a relief.

BTW, I saw the Civic Si at the auto show today. I just can't wait to drive one. The red Si guage lighting was classic, the LSD, underbody-pan for less Cd. The K-series would take some getting used-to, though. The Si Sedan will be identical, but 2 more doors, and expected to come out in April. 32 mpg hwy isn't bad.

RH77

[SVOboy]

PS to all: Look for a front camber kit DIY tonight or tomorrow for the ability to drop the car even further,

[Matt Timion]

Originally Posted by krousdb

The numbers below are corrected for the SuperMID error.

Pre Drop km/L km Temp MPG
2/28/2006 21.90 40.61 18 51.52
2/28/2006 21.24 42.33 41 49.95
3/01/2006 24.20 40.57 28 56.93
3/01/2006 22.61 42.10 41 53.19
3/02/2006 23.86 40.57 30 56.12
3/02/2006 21.50 42.34 41 50.58
3/03/2006 21.17 40.56 18 49.79
3/03/2006 20.73 45.90 39 48.75

Pre Drop ave temp 30.90F
% distance on wet roads 60%
Pre Drop ave FE 52.01MPG

Post Drop km/L km Temp MPG
3/06/2006 25.68 40.57 30 60.41
3/06/2006 22.40 42.24 40 52.68
3/07/2006 24.30 40.52 21 57.15
3/07/2006 23.09 42.26 39 54.32
3/08/2006 23.89 40.55 28 56.19
3/08/2006 23.85 42.26 41 56.10
3/09/2006 24.46 40.46 44 57.53
3/09/2006 25.06 42.20 64 58.94
3/10/2006 24.66 40.48 53 58.00
3/10/2006 23.83 42.21 53 56.06

Post drop ave temp 41.3F
% distance on wet roads 30%
Post Drop ave FE 56.74 MPG

I would say that given the variables of temp, wet roads, varying winds and lower ride height, one cannot extract the effect due to lower ride height alone. I would suspect that most of the gain came form warmer temps and dryer roads.

I tried to run this data today and came into a bit of a snag. Considering that two of the variables are continuous (temp and distance) and that one is categorical, I would need to be using multi-variate stats to determine if there was statistical significance or not. Since this is above my field of knowledge, I took the easy way out: I ran multiple tests.

Distance: Oddly, distance had a negative correlation with MPG. This really means nothing though as your distance was all very close.

Temperature: Temperature correlated to MPG (Pearson's Correlation) at .254. This means that the significance was .30. This essentially means that the temperature has no significant impact on MPG (in your case at least).

Dropping the car: This yielded the most interesting results. Comparing the MPG of the pre-drop and post-drop group yielded a significant result. It was significant to .002, which means that there is only a .2% chance that the drop did NOT affect fuel economy.

In other words, lowering the car works in krousdb's case.

[SVOboy]

In other words, lowering the car works in krousdb's case.

But how much is a matter of guesswork?