Road trip, low speeds not a option.

First, your 12v battery might be going - typically, reduced gas mileage is a symptom. I'm assuming that (since you have a del sol and you're talking about engine timings) you've checked the alignment on all 4 wheels?

I drive 70mph speed limit highways all the time and I get like 42-45.

BTW, know any of the Evo guys in Olathe?

 

1. Bump tire PSI to max on sidewall or 2psi below the max.

2. Drop a bottle of Chevron Techron CONCENTRATE (not Progard from Costco)

3. Shell 87

4. Unload as much weigh as you don't need... pretty much junk

5. Start exercising, shave a few lbs.

 

Sure but then you would get even worse mileage no matter what you did so why bother.

 

a/c usage is probably your biggest worry. 2nd would be the tire psi. (as others have mentioned).

a/c is a delicate balance... you have to keep that hybrid battery cool. if you use windows, it still gets warm by the battery area IMO. try keeping the thermostat above 74.

get tint. hehe (a future plan of mine) it helps with the heat. it is laminate so maybe it helps in the cold too?... shrug.

 

If you wanted to keep a 2007 Prius at speeds of 75 to 80MPH, without taking a big hit on MPG's.

I would keep tire pressure at 42psi (Front) & 40psi (Rear), keep the A/C low, keep overall weight low, and use a bottle of fuel system cleaner.

Check your 12volt battery, get an oil change, and balance your tires with possible alignment..did I forget something?

 

I had 12 volt battery replaced and ever since my mileage has been 30 to 33 mpg's. Tire pressure 38 front, 36 rear with new Michelin tires. Taking in to dealer tomorrow, thought computer may not have been calibrated correctly when reset after battery replacement. What should I ask the dealer to do? Nothing extra in car. The bottle of fuel cleaner sounds like a good thing.

 

Is it really a fair comparison considering something is wrong with your mom's car? Your Civic could never match her car's MPG numbers if both cars were in proper working condition.

No, taping up the fender gaps and such will have no quantifiable affect. The only time this is even remotely quantifiable is on very high speed race cars trapping 160mph+ and even then it is rare to see racers taping up the gaps. I've seen plenty of street cars doing it at the track and it is quite laughable to see a taped up car trapping 100mph or less in the 1/4. I'd say forget the tape and keep your dignity intact.

The other suggestions people have listed are what I would recommend i.e. tire pressure, reduced weight, etc.. Most importantly, just drive safe. No amount of time or fuel savings is worth you getting hurt mate.

 

After always reading that the Prius MPG is lower on highway and at higher speeds I was surprised when I drove to my hometown a day after I got mine and averaged 54.2 mpg. I had no idea what to expect, and I used cruise control (which in my other car enjoyed speeding up.. and then slowing down.. and then speeding up.. you get the picture). So, my suggestion.. cruise control! Be safe!

 

Try driving 72 - 73 mph instead of 80 mph. I realize that it will take longer and that you'd prefer to drive 80 mph vs a slower speed. But after doing the other items (inflating tires, removing excess weight, moderating A/C usage) the one last thing that you can do to help is to lower your speed.

How many days do you plan on driving to make this trip? How many breaks? For how long? How many hours of driving per day? I'm assuming you plan on driving this in 2 days, probably 10 hours of driving time (over a 12 hour time span) the first day and the remainder on day 2. So, ideally, you'd only spend 15 hours of actual driving at 80 mph. 16 hours of driving at 75 mph. 16 hours and 30 minutes driving at 72 - 73 mph.

Yes, that's a whole 1.5 hours. And for your trouble, you won't be worried about highway patrol cars and planes, radar, etc. You'll be moving well with traffic, as opposed to having to slalom between cars that "are in your way" which will cause you aggravation. You'll also get about 10% better gas mileage than at 80 mph.

Just saying.....

 

I believe the only problem with Mom's car is that it is driven on very short trips.

Align the wheels & pump up the tires is about all you can do.

 

I would check the alignment.

 

Ok - it is Sept 2. How was the trip ?
I live outside of Wichita - similar area that you are from. I can tell you after returning from a 4K trip that KS is part of the problem. I used to blame it on the wind. I drove through the mountains in TN and GA with A/C and cruise control and exceeded 50 mpg with speeds from 75-85; which I have never been able to do in KS.

So if you have not left on your trip yet ? I would --
tire pressure, fuel system cleaner ($8 Wal-Mart- white metal can- cant remember the name -- but the only white metal can there is - my brother uses it in on jet planes - add to fuel tank), do a search here and Clean the throttle plate and EGR sensor - I used EGR electrical sensor cleaner on both parts - read the warnings! - and I replaced my air filter. Good Luck