19bonestock88's 07 "Malibu Eco" build
 

So, this all began about two months ago when I was complaining about my cars fuel mileage, but I usually would add, "I'm sure it would help if I slowed down"... I was at the time driving aggressively and pretty fast, usually 10-15miles over the speed limit on my commute, and getting 22mpg...

I decided I would plug in my UltraGauge and see if I could improve this number...

Trip averages(on the un calibrated device) went from around 25 indicated mpg, to around 35... Intrigued by this apparent 45% fuel savings just from driving a little smarter(slower), I started pushing further, and on a really slow trip into town, I managed an indicated 36.1mpg...
And so, the Eco-modding began...

I decided that since everybody is making "Eco" versions of existing models, with minor weight reduction/aero improvements, I figured I would try that out...

I started with an air dam extension and some rear tire spats, partly to offset my buying a wider than original tire...

http://i1140.photobucket.com/albums/...sleempvgn.jpeg
In this photo, I was also experimenting with a partial lower grille block, which did basically nothing...

For a couple weeks, I managed trips to work between 36 and 37mpg indicated, and including all my short trips, the car itself was slowly creeping up past 30mpg average, over a couple tanks of fuel...

On the highway(cruise set at 80mph), I noticed I could get right at 30mpg indicated, and decided I was shooting for a 33% improvement, to 40mpg indicated...

... And then I started with grille blocks...

http://i1140.photobucket.com/albums/...svofovjcj.jpeg

This was phase one, done yesterday... Full, 100% grille blockage... A good thought,but about eight miles into my drive to work, the engine got too hot(225F) and I removed my upper grille block, leaving the lower in place for the remainder of the drive... Now, the engine was partially warm when I first set off, but despite having to stop(engine idling during this) and remove the upper grille block, that trip returned a shocking 39.3mpg indicated... The best I got before with similar conditions, was about 37 indicated, with lower speeds...

When both grille blocks were on, there was a noticeable reduction in throttle(load) required to maintain 55mph... Usually, it takes between 36.1 and 36.5% on flat ground, but I found the car wanting to accelerate past 55 with as little as 35.7%... Intake temps were probably about 20* above ambient during this, which also helps with mileage...

I'm currently revising my upper grille block in hopes of not having to remove it tonight

I would leave the upper and open the lower a little bit. Kind of like the cup cars do. The uppers are blocked and they adjust the lower with tap to get the temp they want.

Had I seen this before cutting, I might have started there... However, I opened a 1.5" by 19" rectangular hole in the lower half of the upper grille block and went to work last night... The trip started with a cold engine, but I did make it fourteen miles or so before the engine got uncomfortably hot and I had to take the upper back off... Trip average was 38.0mpg indicated, still not bad all considering... This gives me some insight into the FE benefit of a block heater...

I plan on opening the existing hole in the upper slightly and trying again, as the temp climb from 195 to 210 was way slower than before, so I might only need one more revision to the upper to stabilize the running temp between 200 and 210 degrees(my goal)

So, yesterday I made the existing hole in the upper grille block 1/2" higher, roughly an inch and half wider on top(width not changed at bottom), and the half inch strip between the hole and the bottom edge removed... I did drive all the way to work and back in this configuration, but at the end of the trip to work, temperature was flirting with 220*, and at the end of the trip home, the story was the same, but I decided to try cycling the heater to remove heat, with much success... I'm not comfortable with temps staying above 210F(even with no cooling fan kick on until 228F), so I enlarged the opening again, carving a "bow tie" emblem in the center, just 3/8" above the opening, and raising the top of the opening 3/8" around the bow tie, for visual effect... Considering how well it mounts up, and the nice, almost dealer accessory-like appearance it has, I'm considering the upper grille block done, except for paint and semi-permanent mounting(not plastic tape)... If my current version of the upper doesn't bring the temps down enough(it was pretty close), I'll make small holes in the upper half of the lower grille block...

The trip to work(starting with a cold engine) averaged 39.0mpg indicated, and the trip home averaged 41.0mpg indicated, this was due to my driving to the fuel station and thus preheating the engine and while I was getting fuel the UG shut off, resetting the trip mileage figure

So, I've been working on my grille block, and did a passenger wiper delete... But, ever since my trip into the mountains, my fuel mileage has been consistently low, by between 5 and 10 percent... I'm not sure if high engine temps during the trip are to blame(breaking down my non synthetic oil), or my focus has dulled or what?

It just occurred to me that I figured out that running the A/C drops engine temp on the trip into the mountains, and I've been running it constantly on, even if I didn't need it for comfort... Maybe that's the difference?

Not sure... I know non-synthetics will change viscosity over time, regardless of temperature. And those new Malibus get pretty crazy mpg for a full-size car, right?

It could... My oil is about halfway through its usual 3k-ish mile interval, but I spent perhaps half of that mountain trip twenty degrees above normal trip... I was never actually overheating, but was between 215 and 225 degrees on most climbs...

And yes the new Malibus can pull down some pretty killer mileage... Some guys over on CMF are getting 50+mpg averages with the Hybrid... They're also much bigger and heavier than my 2007 is, so that's pretty amazing...