First Gen xB: Initial results after smooth wheel covers, LRR tires: 43mpg!

[brickinthewind]

Hey all,
That's right, he of the double-entendre user name is back! I've posted here before, but not in a couple years. I've been incorporating all the right techniques - driving smoothly, setting up my driving style to brake as little as possible while still being safe, reading traffic correctly, etc. I do a little EOC and pulse and glide on long trips down long hills. Generally been getting 30-35mpg, which is a nice improvement over EPA but not numbers to sing from the rooftops. I put some old rims and tires I had from back in my "tuner" days back on just to use them up, and even those 205/40/17 flat monsters were capable of close to 35mpg on a trip with 3 people, a dog, and lots of stuff!

Recently, though, I've gotten serious again: needed new tires, so I got Goodyear Assurance Fuel Max in my size and smooth 15" wheel covers from Rocky Mountain - the premade ones for about $80. I figure that with a 4.6% improvement they will pay for themselves. The tires will get me anywhere from 2-3% improvement (observed by some guy on another forum semi-scientifically) and 4% (claimed by Goodyear) over normal OEM stock replacement tires. Nitro fill up to the max on the sidewall - 44psi. I went with the Goodyear since it was either those or the Kumho Eco Solus in my size, and I wanted to retain an accurate speedo reading even though I use the Rev app and a Kiwi Wifi OBD-II scanner. The Kumhos have poor wet braking and cornering performance in Tire Rack tests, so Goodyears it was.

Results? Well, going from a 205/40/17 tire/wheel combo to the 185/60/r15 and the smooth wheel covers got me from 32-33 to an observed partial tank of 3.4 gallons and 146.5 miles between fillups. This was highway and backroad and city driving, with some stretches of slow, empty, rolling backroads and some EOC and mild drafting on the freeway. Also, a few hundred pounds of luggage, girlfriend, and dog to weigh me down - of course, it was mostly luggage and dog. Pretty excited about the results, and will post more as the trip progresses or I refill on the way home. Plus, I love the smooth wheel cover look on the xB.

[brickinthewind]

Another personal best! This tank included driving up to Tahoe from the Sacramento area, so some climbing that would lower my MPG, followed by driving around the lake and some stop and go traffic at the lake. (some good opportunities for EOC driving around Lake Tahoe and it's a slow drive anyway) Coming down from Tahoe included lots of EOC opportunities as well. 255 miles, 4.6 gal, and I made sure to top up when filling up to ensure the pump didn't shut off early. Higher PSI at higher altitude (2-3 more psi at 5000 feet than at sea level?) may have played some small part.

The trip from the Sacramento area home to the Bay got me down to 60-70% full, so maybe I can post my next tank next week or so? I was definitely this guy driving home from Sac - - so that tank should be a good one too.

[cfg83]

brickinthewind -

Great results, and looks cool too!

CarloSW2

[brickinthewind]

Thanks Carlos, and thanks to this forum for all the motivation and great ideas. I did some math on fuel savings with the smooth wheel covers based on the 4.6% figure, and I figure at $3.75/gal, they pay for themselves pretty quickly even if you buy the retail-priced ones at Rocky Mountain Wheel for about $80/4. I did a spreadsheet that calculates the benefit of those covers and the (assumed 2.5% based on a conservative estimate from another user online and below Goodyear's optimistic 4% mileage increase) tires over the 65k tread life of the tires. The combined increase of both makes them almost free, and the covers will outlast the tires and give more benefit for the $.

Only downside is that I curbed the nice stainless smoothie wheel covers for the first time today, and there's a small scratch and dent on one - they stick out a little from the tire. Have to be a little more careful there.

[brickinthewind]

I actually tooted a little too quickly on the last tank, Margaret. Last tank measurement and this one are in error, since the last fillup was not complete even though I topped up and the pump stopped twice. So this tank was under the correct mileage, last one over. Combined is 42.35mpg though, so that should be accurate. Similar to the first (correct) tank in the thread title.

I'm going to officially claim 43mpg as my new standard mpg and watch the fuel savings roll in! These mods, perhaps combined with a few extra tricks (although I was using most of them before) are getting me 14mpg over EPA!

[SentraSE-R]

Cool, another xB1 driver. Do you use a Scangauge or Ultragauge for instantaneous and average mpg?

Your last tank fill needs editing, as it shows you filling with 32.8 gallons, for a 6.1 mpg tank.

I live about an hour from Sacto. We should get together to compare hypermiing technique. I switched from the stock wheels/tires to 205/50-17s, and they haven't hurt my mpg. Since switching to them, I've run a string of 7 of 10 tanks >50 mpg

[NeilBlanchard]

The other thing to know about those wheel covers is they tend to fall off after year or two; especially on the right side if you drive on 2-lane bumpy roads. The outer surface is stainless steel, but the spring "fingers" that hold it on the rim are not.

[brickinthewind]

Neil, that's no bueno. I read a little bit about them but didn't see any reports of that happening. I could see why, with a flexible steel wheel and a non-flexible wheel cover. Hope I can find some way to keep them secured.

Darrell, fixed, thanks. I'm very surprised you're not losing mileage on the 205s, a wider, flatter tire. I switched to my original "tuner" tires and wheels just to wear them out earlier this year and couldn't get above 34mpg or so. They wore out, so the Goodyear LRR tires went back on. I would still say when those wear out for you you could get a few more MPGs out of the OEM wheels and tire size, LRR tires or no. I just don't see how they couldn't help you - it must be your technique that's getting better!

I use the Rev app on iPhone (for long trips I try to set up the iPad in the car with the Rev app since it's easier to read but it's a hassle to install and I won't leave it in the car) and the Kiwi Wifi adapter. I don't leave the Kiwi in the car at all times since I don't drive to work (mostly just drive on my weekends) so sometimes I forget the Kiwi when I'm going out to the car. It drains the batter if left in and turned on so I don't want to come out to a dead battery like some have because they forgot to turn off their Kiwi.

I'll have to check out more of your posts for technique! If I know I'm going to be up in Sac I might give you some notice and try to stop by. My new latest tricks are EOC when entering a parking lot when I know where my space is going to be and choosing a space that lets me stop quickly and turn off the engine. That and EOC on off ramps when no one is behind me, and EOC when approaching a red light I expect will keep me stopped for 30 sec or more.

[SentraSE-R]

Brickinthewind,

See my tall tire test. The test summary is on page 6 of the thread.

I'm in the Vallejo/Fairfield area. Which part of the Bay Area are you in?

[brickinthewind]

Ah, I was going to ask why they were 50s, as my "tuner" tires were 205/40/17s. I see now what the taller tires are doing for you. Keep the engine revving lower in 5th, especially, and perhaps roll over bumps in the road more smoothly. I went with stock to have correct speedo, odometer, and mileage readings, since I don't have the Kiwi plugged in at all times.

I hadn't fully understood how to integrate DFCO in my driving technique, but I certainly could benefit from it after reading about it in more detail here and especially your posts on the DFCO working above 1500rpm on the xB. I could absolutely have benefited from that on the hills around Tahoe and driving down from Tahoe where I needed to turn on my engine after EOC to have enough power in the brakes. I had previously been using the parking brake occasionally as a "drag brake" and windows down (the Box catches wind nicely with the windows down, lol) but in faster sections or when coming on traffic I had to bumpstart to get braking power back. Now I can DFCO alternating with EOC (EOC when I need to pick up speed by using gravity) down those mountain passes - good call!

I'm in Oaktown, didn't realize you were so close. Busy schedule of 46+ hours per week (especially around the holidays) and lots of responsibilities at home, along with trying to get enough exercise every day, but we'll have to find some way to get together.