Maximizing MPG driving 10k miles in a rental (minivan or SUV)

[Big_Ben]

Ok I may ignore the mirrors then if the benefit doesn't match the added risk/hassle.

wmjinman: You Jimmy is rated 17 mpg combined and you got 24 mpg that is an increase of ~40%. A grand caravan (and most other vans) are rated for 23 combined. Would only need a 30% increase to hit 30mpg. I know it is pushing it but with good driving and a few mods I think that could be attainable (from what I've been reading).

On the issue of roof racks, if the van comes with cross bars I had planned on removing them but what about just the bars running front to back? Do those make much difference if there are no crossbars?

I've read a few aero projects on here and am debating having a good amount of coroplast on hand before picking up the mini-van. Not sure what the best balance of time/effort vs mileage increase would be though. I think a belly pan is out of the question but an air dam on the front or just flaps for both sets of tires may not be.

I think I will also cover the wipers with coroplast instead of trying to take them off. Not sure if I will try and leave it short enough so the wipers can still function without taking it off or whether I will extend it all the way to the window to try and smooth that transition.

[Big_Ben]

Also in regards to tire pressure. Some of the newer vans have tire pressure sensors and I was wondering about the max pressure I could inflate them before setting it off and also whether a rental car company could/would check something like that?

[jamesqf]

Thinking outside the box for a minute, maybe the best modification you could do would be to take two small (and economical) cars? You also get the benefit of being able to make separate side trips, send one person into town for supplies, etc.

[pete c]

Two small vehicles could make sense as the rental companies sometimes rent their econoboxes very cheaply. But if there are going to be many tolls/parking expenses, better to stay with a single vehicle.

[Big_Ben]

I considered taking 2 vehicles but the cost was more than a benefit.

From an existing vehicle perspective we could save rental fees but would be adding 10k miles to personal vehicles which would add maintanence costs and depriciation in resell value. The only options in personal vehicles would be a 2010 taurus or 2002 Camaro, neither of which are that great an improvement over a rented mini-van in mpg.

From a rental perspective at first I thought it may be a better deal considering most Econo cars are ~$600-650 for a monthly rental and most mini-vans were double that. I happened to shop around enough to find a monthly mini-van rental with unlimited mileage for $980 after tax. So an Econo car would need to get more than 2x the mileage to justify it based on price + fuel costs alone.

Storage in small economy cars may be an issue as well, even with 2. We plan on visiting several national parks and camping in the area so we will probably have a fair amount of extra equipment in addition to a month of normal clothing, etc. With a mini-van it is possible to store/remove one of the middle seats to increase storage space, keep weight balanced, and still fit 5-6 comfortably. Not to mention that several camping places may limit # of vehicles per site and a national park yearly pass covers an entire carload so would need 2 with 2 vehicles.

I created a spreadsheet with vehicle rental rates, epa mpg ratings, and fuel costs for every rental vehicle available and calculated per person total based on a comfortable number of passengers. The best value is a full sized 15 passenger van loaded with 12 people and rear seat removed for storage but we won't have that many people. A Nissan Versa or Ford Focus are both great values but only hold 4-5 so we would need 2 and could have storage issues; it may work if we had 8 people going though. After that comes to deal I found on a Grand Caravan. For 5-6 people it seems like the most economical option.

[wmjinman]

When I took the roof rack off my Jimmy, I just did the whole thing in one whack, so I don't know how much the cross bars were vs. the longitudinal ones. But from reading the various posts on here, I'm guessing the cross bars are where most of it is - so the gains from doing the rest of it might be minimal.

I'd say experiment with folding the mirrors in. Just 'cuz I didn't see a great improvement doesn't mean it won't be in the van you get. But when you approach congestion, be prepared to either pop them back out, or for it to get "hairy"!!!

On the tires, I guess the "prudent" thing would be to put them to max sidewall & then make sure the tire pressure sensor alarm doesn't go off. If it does, adjust until it goes back off, right?

I didn't look too closely at my Jimmy's percentages vs. what your goal was, so sorry about that. I guess the point I was trying to make was just that EXTREME improvements can be had, but it may take EXTREME efforts to do it! - like driving everywhere at 40 mph!!! But yeah, if my gas logs are showing 40% over EPA, and you wanna get 30% over, then I guess the "shot in the dark guess" would be you could probably do it while being LESS extreme than I was. - and my tanks did include at least 2 or 3 cold starts per day, and probably at least 30% "city" driving with stoplights, etc.

Belly pan - yeah, probably a huge effort for a rental car. I plan to do one for my own car, but due to the huge effort, I haven't done it yet! LOL!!! And I've read a couple reports on here where guys went to all that trouble and then were very dissappointed by seeing much smaller gains than they expected. - That would kinda suck!!

Windshield wipers - don't be surprised if you don't see any improvement. From what I hear, it's miniscule, at best. It's pretty dry where I live, so we can go a week or more without rain. So I thought I'd do an A-B-A test with the blades off vs. on in the Jimmy. - Didn't see any difference at all .... exact same averages both ways. I haven't tried the test on my Swift yet. The way it's hood/windshield interface is shaped, I think there might be more of a chance to see a difference there, so gotta test that.

Air dam - I'd say it depends on what your van looks like when you get it. If you can squat down a few dozen feet in front of it & see all kinds of lumpy machinery hanging down below the line of whatever smooth front end it has - AND - you can figure out a way to attach it without going into "major engineering/manufacturing mode", then yeah - it'll probably help you. If not, then it might not. Hard to say. One of those "play it by ear" things.

You know, if your co-horts are all into the hypermiling thing, you guys could have a really fun game by competing against each other to see who's tank "wins" with the highest MPG. That would tend to keep you all on your toes.