Florida Head + AC = -4 MPG - Fuel Economy, Hypermiling, EcoModding News and Forum

hawk2100n · 03-19-2012, 10:32 PM

I just took a weekend trip to the 12 Hours of Sebring. It's starting to heat up here in Florida and that means AC or I will die. I have been averaging a consistant 38-39 MPG without the AC in the 2000 miles since I bought the car. But the highway jaunts required the AC and went through a full tank each and they killed it at 35.5 there and 34.5 on the way back. I did my best to reduce the AC load but it was too hot. I had one tank in the middle where I got away with windows down for about 80-90% and that was 39.5 mpg. But that's the cost of living down here I guess.

Also, my CEL came on about mid way back. Suspected the O2 Sensors after a successful attempt at using the spark plug non foulers in the second bung on the header. Turns out it was a code for the crank position sensor. Visual inspection showed me that I forgot to tuck the wire in place on the timing cover after that replacement a couple of weeks ago and the alternator belt rubbed through the insulation. I cleared the code and tucked the wire away but now I have to dread taking the timing cover off to repair it correctly with a new sensor or hopefully I can just splice in new wires. The good thing is the sensor seems to be working with no CEL after the clear and the car backs up to the distributor in the event of a failure so it will continue to run. But still, I feel both dumb and lucky I didn't get stranded on the side of the road.

FXSTi · 03-19-2012, 11:30 PM

Can you pulse and glide the A/C? Turn it on until you are comfortable and then turn it off until you can stand it no longer.

I've not been to Florida for a long time, maybe the humidity and heat are to much to get away with that.

hawk2100n · 03-20-2012, 12:29 AM

Quote:

Originally Posted by FXSTi

Can you pulse and glide the A/C? Turn it on until you are comfortable and then turn it off until you can stand it no longer.

I've not been to Florida for a long time, maybe the humidity and heat are to much to get away with that.

I tried that, and frankly it just doesn't work. The normal cycle of the AC is an attempt at that, but I have to keep the fan on 2 just to keep up sometimes. Might have to invest in some ceramic tint. As much as I drive it will be worth it. Bought it February 15th and have driven ~3500 miles in it as of today. I usually fall between 2500-3000 miles per month.

tru · 03-20-2012, 01:28 PM

i went with some heavy tint and it helped some, but realistically it doesnt cut it in a car. best thing to do is plan your trips early in the AM or after sunset to cope with the heat. pulsing the air does seem to work in my car but its annoying. i usually run the air until the cabin cools down, then switch to recirculate with the air off. recirculating the cabin air will keep the cool in a little longer than bringin in fresh 90 degree air.

hawk2100n · 03-21-2012, 01:43 AM

Quote:

Originally Posted by tru

i went with some heavy tint and it helped some, but realistically it doesnt cut it in a car. best thing to do is plan your trips early in the AM or after sunset to cope with the heat. pulsing the air does seem to work in my car but its annoying. i usually run the air until the cabin cools down, then switch to recirculate with the air off. recirculating the cabin air will keep the cool in a little longer than bringin in fresh 90 degree air.

I have been doing that too. But I get tired of sweating on and off every 5 minutes or so so I just leave it on. I think tint may be my next investment.

Ladogaboy · 03-21-2012, 03:37 AM

From what I've heard, tint will limit your A/C use, but it might not eliminate it completely. But, in terms of blocking out heat from the sun, if you're going to go with a tint, Huper Optik Drei is the best (according to my research).

bhut2180 · 03-28-2012, 08:08 PM

The tint will make a difference for a little while, but if your car is sitting outside in the florida heat that benefit disappears quickly, I find its necessary to park in the shade. As for driving, I think AC is just necessary

deathtrain · 03-28-2012, 10:00 PM

I didnt use the AC but once or twice last summer here. I just sucked it up and continued to lose weight.

Ecky · 03-28-2012, 10:55 PM

I started parking my car in my garage whenever possible to help fight the heat. Does it sit in the sun? Maybe you can get one of those canvas car cover structures?

Doesn't help when you have to leave it in a parking lot, of course.

hawk2100n · 03-29-2012, 12:18 AM

Quote:

Originally Posted by Ecky

I started parking my car in my garage whenever possible to help fight the heat. Does it sit in the sun? Maybe you can get one of those canvas car cover structures?

Doesn't help when you have to leave it in a parking lot, of course.

Yeah I live in an apartment with little shade available and no garage so that's not really an option. The parking lot has almost no shade available. I usually am ok with rolling the windows down and letting the heat vent with no AC on a short drive but anything longer than about 30 mins I have to turn it on if I don't want to sweat through my clothes.